Symmetricom Gps Receiver 58503B Users Manual

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097-58503-13
Issue 2: Jul 00

58503B
GPS Time and Frequency
Reference Receiver
and
59551A
GPS Measurements
Synchronization Module
Operating and Programming
Guide

Copyright © 2000 Symmetricom, Inc. All rights reserved. Printed in U.S.A.

This guide describes how to operate the Symmetricom 58503B GPS Time and Frequency Reference Receiver
and
59551A
GPS
Measurements
Synchronization Module via the RS-232C port(s).
The information in this guide applies to instruments
having the number prefix listed below, unless accompanied by a “Manual Updating Changes” package indicating otherwise.

Warning Symbols That May Be Used In This Book

Instruction manual symbol; the product will be marked with this
symbol when it is necessary for the user to refer to the
instruction manual.

SERIAL PREFIX NUMBER:3805A and above
(58503B), 3805A and above (59551A)
Instruments with serial numbers below 3805A may
have earlier versions of firmware installed. There
are no operator-specific differences in previous versions of firmware.

FIRMWARE REVISION:3805A and above
(58503B), 3805A and above (59551A)
Firmware revision can be identified by using a
“*IDN?” command sent to the Receiver via RS-232C
port. See the section “Connecting a Computer or Modem,” in Chapter 2, “Serial Interface Capabilities,”
of this guide for instructions on connecting a computer or modem to these products.
For assistance, contact:
Symmetricom, Inc.
2300 Orchard Parkway
San Jose, CA 95131-1017
U.S.A. Call Center:
888-367-7966 (from inside U.S.A. only – toll
free)
408-428-7907
U.K. Call Center:
+44.7000.111666 (Technical Assistance)
+44.7000.111888 (Sales)
Fax: 408-428-7998
E-mail: ctac@symmetricom.com
Internet: http://www.symmetricom.com

Indicates hazardous voltages.

Indicates earth (ground) terminal.

or

Indicates terminal is connected to chassis when such connection
is not apparent.

Indicates Alternating current.

Indicates Direct current.

Contents
In This Guide
1

Front and Rear Panels at a Glance
58503B Front Panel at a Glance 2
58503B/Option 001 Front-Panel Display/Keypad at a
Glance 3
58503B Rear Panel at a Glance 4
59551A Front Panel at a Glance 5
59551A Rear Panel at a Glance 6

2

Serial Interface Capabilities
Chapter Contents 2
About the RS-232C Serial Port(s) 3
PORT 1 Rear-Panel RS-232C Serial Port 3
PORT 2 Front-Panel RS-232C Serial Port (59551A Only) 4
Connecting a Computer or Modem 5
To Connect the GPS Receiver to a PC or Modem Via the
Rear-Panel PORT 1 6
Connecting to the Personal Computer (PC) 6
Connecting to a Modem 6
Making Your Own Cables 8
Configuring the RS-232C Port(s) 9
Making Changes to the Serial Port Settings (If Needed) 10
Configuring PORT 1 of the 59551A 10
Configuring PORT 1 of the 58503B and PORT 2 of the
59551A 10
Determining the Serial Port Settings 11
Standard 58503B and 59551A 11

3

Visual User Interface
Chapter Contents 2
Using and Reading the Visual User Interface (the Receiver
Status Screen) 3
Tutorial on Using the Status Screen to Interface With the
Receiver 3
Demonstration of Holdover Operation 8
Receiver Status Screen Data 11
SYNCHRONIZATION Section of the Status Screen 12
SYNCHRONIZATION Summary Line 12
SmartClock Mode 12
Operating and Programming Guide

iii

Contents

Reference Outputs 13
ACQUISITION Section of the Status Screen 14
ACQUISITION Line 14
Tracking, Not Tracking 14
Time 16
Position 17
HEALTH MONITOR Section of the Screen 18
The Receiver Status Screen at a Glance 20

4

Command Quick Reference
Chapter Contents 2
An Introduction to GPS Receiver Commands 4
SCPI Conformance Information 4
Command Syntax Conventions 4
Command Presentation 4
GPS Satellite Acquisition 5
1 PPS Reference Synchronization 7
Operating Status 8
System Time 10
Programmable Pulse Output (59551A Only) 11
Event Time Stamping (59551A Only) 12
Serial Interface Communication 13
Receiver Initialization 14
Receiver Identification/Upgrade 15
Receiver Commands at a Glance 17
Status Reporting System at a Glance 18

5

Command Reference
Chapter Contents 2
Command Syntax Conventions 4
Description Format 5
Commands and Returns 5
Query-Specific Information 6
Description of Response Formats (ASCII-encoded)

iv

6

Operating and Programming Guide

Contents

GPS Satellite Acquisition 7
1 PPS Reference Synchronization 27
Operating Status 39
System Time 73
Programmable Pulse Output (59551A Only)
Event Time Stamping (59551A Only) 89
Serial Interface Communication 100
Receiver Initialization 109
Receiver Identification/Upgrade 113

A

Error Messages
Introduction 2
Reading an Error 2
Error Queue 3
Error Types 4
No Error 4
Syntactic Error 4
Semantic Error 5
Hardware/Firmware Error
Query Error 5
General Error Behavior 6
List of Errors 7

B

83

5

Command Syntax and Style
Appendix Contents 2
Command Types, Format, and Elements 3
Command Types 3
Command Formats 3
Common Command Format 3
SCPI Command and Query Format 3
Elements of SCPI Commands 4
Common Command Syntax 4
Subsystem Command Syntax 4
Abbreviated Commands 5
Keyword Separator 5
Parameter Data Types 5
Parameter Separator 6
Query Parameters 6
Suffixes 6
Suffix Elements 6
Suffix Multipliers 7
Command Terminator 7
Operating and Programming Guide

v

Contents

Using Multiple Commands 7
Program Messages 7
Program Message Syntax 7
Elements of Response Messages 9
Response Messages 9
Response Message Syntax 9
Response Formats 10
Reference Documentation 12

C

Receiver Firmware Installation
Downloading New Firmware Using SatStat Program

D

2

Performance Tests
Introduction 2
Operational Verification 2
Complete Performance Tests 2
Test Record 2
Equipment Required 3
Before You Start 4
Operational Verification 5
Introduction 5
Power-Up Procedure 5
10 MHz Verification (58503B Only) 6
1 PPS Verification 6
IRIG-B Verification (59551A Only) 7
Time of Day and PORT 1 RS-232C Serial Interface
Verification 8
Antenna Power Verification 9
Front Panel Display/Keypad Verification (58503B Option 001
Only) 10
Time Tagging (Stamping) Verification and Programmable
Verification (59551A Only) 11
Programmable Pulse Verification (59551A Only) 13
Operational Verification Conclusion 15
In Case of Difficulty 16
Complete Performance Tests 17
Preliminary Test Setup 18
Test 1: 10 MHz Frequency Accuracy and 1 PPS Jitter (Locked to
GPS) 19
Specifications Tested 19
Procedure 19
Test 2: 10 MHz Holdover Aging and 1 PPS Accumulated Time
Error (Unlocked) 22
vi

Operating and Programming Guide

Contents

Specifications Tested 22
Procedure 22
Test 3: 1 PPS Time Accuracy (Locked) 24
Test 4: 10 MHz Frequency Stability (Time Domain) and Phase
Noise (Frequency Domain) Measurements 24
Frequency Stability (Time Domain) 24
Phase Noise (Frequency Domain) 24
58503B Performance Test Record 26
59551A Performance Test Record
27

E

58503B Specifications
Specifications and Characteristics
GPS Receiver Features 2
Other Information 5
Options and Accessories 5

F

2

59551A Specifications
Specifications and Characteristics
GPS Receiver Features 2
Other Information 5
Options and Accessories 5

2

Command Index
General Index

Operating and Programming Guide

vii

Contents

viii

Operating and Programming Guide

In This Guide
Chapter 1, “Front and Rear Panels at a Glance,” provides overview
of the Receiver’s indicators, inputs, and outputs.
Chapter 2, “Serial Interface Capabilities,” provides RS-232 serial
interface port connection and configuration instructions.
Chapter 3, “Visual User Interface,” which is subtitled “Using the
Receiver Status Screen,” provides information on how to use the
Receiver Status screen and the SatStat program. An illustrated foldout
of the Receiver Status screen, which is a comprehensive summary of
key operation conditions and settings, is provided at the end of this
chapter.
Chapter 4,“Command Quick Reference,” is a quick reference that
summarizes the Receiver commands. The commands are presented or
grouped by their functions. A foldout sheet that presents all of the
commands on one side (Receiver Commands at a Glance) and
illustrates the status reporting system on the other side (Status
Reporting System at a Glance) is provided at the end of this chapter.
Chapter 5, “Command Reference,” provides a description of each
command that can be used to operate the GPS Receiver.
The commands are grouped by functions. The functions are grouped
and ordered the same as they are in Chapter 4, “Command Quick
Reference,” and on the foldout “Receiver Commands at a Glance
(cont’d).” A comprehensive discussion on how you can monitor and
control alarm conditions using the status registers is also provided in
this chapter.
Appendix A, “Error Messages,” lists all error messages the Receiver
could generate along with descriptions of possible causes for the errors.
Appendix B, “Command Syntax and Style,” provides an overview of
the Standard Commands for Programming Instrument (SCPI) syntax
and style to help you program the Receiver.
Appendix C, “Receiver Firmware Installation,” provides a
procedure for downloading new firmware to the GPS Receiver.
Appendix D, “Performance Tests,” provides procedures that verify
the GPS Receivers operate properly and meet electrical performance
specifications. Electrical performance is tested against the
specifications listed in Appendix E, “58503B Specifications,” and
Appendix F, “59551A Specifications,” in this guide.

Operating and Programming Guide

ix

In This Guide

Appendix E, “58503B Specifications,” lists the product specifications
and characteristics.
Appendix F, “59551A Specifications,” lists the product specifications
and characteristics.
Command Index, lists all of the commands alphabetically and
provides page references.
General Index

x

Operating and Programming Guide

1

Front and Rear Panels at a Glance

Chapter 1 Front and Rear Panels at a Glance
58503B Front Panel at a Glance

58503B Front Panel at a Glance

1 When the Power indicator
3 When the Holdover indicator
illuminates, it indicates that the
illuminates, it indicates that the
proper input power is supplied to the
Receiver is NOT locked to the GPS
Receiver.
signal. The Receiver is keeping time
based on the internal reference
oscillator signal. The internal
2 When the GPS Lock indicator
reference oscillator will determine
illuminates, it indicates that the
the accuracy of the 1 PPS signal and
Receiver is receiving the GPS signal
the 10 MHz reference output.
and is locked on one or more
satellite(s).
4 When the Alarm indicator
illuminates, it indicates that the
Receiver has detected an internal
condition that requires attention.

1-2

Operating and Programming Guide

Chapter 1 Front and Rear Panels at a Glance
58503B/Option 001 Front-Panel Display/Keypad at a Glance

58503B/Option 001 Front-Panel
Display/Keypad at a Glance

1

An alphanumeric display for displaying time, position (i.e., longitude,
latitude, and altitude), and Receiver status. The display is a highly visible
twelve-character vacuum-fluorescent display.

2

Status LED indicators:
When the Power indicator is illuminated, it indicates that input power is
supplied to the Receiver.
When the GPS Lock indicator is illuminated, it indicates that the
Receiver is tracking satellites and has phase-locked its internal reference
to the reference provided by GPS.
When the Holdover indicator is illuminated, it indicates that the Receiver
is not phase-locking its internal reference to the reference provided by
GPS. Typically, this would happen due to loss of satellite tracking.
When the Alarm indicator is illuminated, it indicates that the Module has
detected a condition that requires attention.

3

Eight MODE keys with associated LEDs for front-panel access to time,
position, and status information: Time, Long (longitude), Lat (latitude)
Alt (altitude), Sat (number of satellites tracking), Status (Receiver or
system status), and Serial Port (serial port settings). Each key selects a
different display mode. Also, pressing Shift and Alt key in sequence clears
instrument alarm.

Operating and Programming Guide

1-3

Chapter 1 Front and Rear Panels at a Glance
58503B Rear Panel at a Glance

58503B Rear Panel at a Glance

1 ANT N-type (female) connector for
GPS Antenna connection.
2 PORT 1 RS-232C, DB-25 (female)
serial interface port for remote
control, monitoring, and
downloading of the Receiver’s
memory data and upgrading
Receiver software.

Option 002 1 PP2S
(One-Pulse-Per-Two-Seconds)
connector for outputting a pulse
every other second, synchronized to
the even seconds in GPS time.
Pulses occur on even-numbered
seconds (i.e., 2 seconds, 4 seconds,
etc.).

6 Alarm output for external devices
(such as red light, bell, or horn) to
3 10 MHz OUT output for user-specific
indicate that the Receiver has
applications.
detected an internal condition that
requires attention.
4 1 PPS connector for outputting a
continuous 1 Pulse Per Second
signal.

1-4

7 POWER input jack.

Operating and Programming Guide

Chapter 1 Front and Rear Panels at a Glance
59551A Front Panel at a Glance

59551A Front Panel at a Glance

1 When the Power indicator

illuminates, it indicates that the
proper input power is supplied to
the Module.

4 When the Alarm indicator
illuminates, it indicates that the
Module has detected an internal
condition that requires attention.

2 When the GPS Lock indicator
illuminates, it indicates that the
Module is receiving the GPS signal
and is locked on one or more
satellite(s).

5 PORT 2 RS-232C, DE-9S (female)
serial interface port for local
monitoring and retrieving data
stored in the Module’s memory
data.

3 When the Holdover indicator

illuminates, it indicates that the
Module is NOT locked to the GPS
signal. The Module is keeping time
based on the internal reference
oscillator signal. The internal
reference oscillator will determine
the accuracy of the 1 PPS signal.
(See specification for Accuracy in
Holdover in Appendix F, “59551A
Specifications,” in this guide.)

Operating and Programming Guide

1-5

Chapter 1 Front and Rear Panels at a Glance
59551A Rear Panel at a Glance

59551A Rear Panel at a Glance

1 1 PPS (One-Pulse-Per-Second)
connector for outputting a
continuous one pulse per second
signal.
2 Programmable Pulse output connector
for outputting pulses at user-specified
time/period.

3 IRIG-B output for outputting
formatted time-code signals. (This
signal is used for general purpose
time distribution and magnetic
tape annotation applications
requiring the time of year.)
4 Time tag input connectors for
receiving TTL conditioned time
tagging signals.

5 Alarm BITE (Built-In Test
Equipment) output for external
devices (such as red light, bell, or
horn) to indicate that the Module
has detected an internal condition
that requires attention. The relay
opens and closes with the Alarm
indicator. (Mating connector is
Amphenol part number 31-224
[glass-filled Noryl] or #31-2226
[Telfon]).
6 ANTENNA N-type (female)
connector for GPS antenna
connection.
7 PORT 1 RS-232C, DB-25 (female)
serial interface port for remote
control, monitoring, and retrieving
of the Module’s memory data and
upgrading Module software.
8 AC POWER input jack. The AC
input jack is standard. The unit
operates from ac voltage. It can also
be operated from dc voltage via this
ac jack by using the supplied IEC
320 dc connector plug.

1-6

Operating and Programming Guide

2

Serial Interface Capabilities

Chapter 2 Serial Interface Capabilities
Chapter Contents

Chapter Contents
This chapter describes how to operate the 59551A GPS Measurements
Synchronization Module and the 58503B GPS Time and Frequency
Reference Receiver via the RS-232C serial interface port. Hardware
connections and configuration are discussed.
This chapter is organized as follows:
•

•

•

2-2

About the RS-232C Serial Port(s)

page 2-3

–

PORT 1 Rear-Panel RS-232C Serial Port

page 2-3

–

PORT 2 Front-Panel RS-232C Serial Port
(59551A Only)

page 2-4

Connecting a Computer or Modem

page 2-5

–

To Connect the GPS Receiver to a PC or Modem Via page 2-6
the Rear-Panel PORT 1

–

To Connect the GPS Receiver to a PC or Modem Via page 2-6
the Rear-Panel PORT 1

Configuring the RS-232C Port(s)

page 2-9

–

Making Changes to the Serial Port Settings
(If Needed)

page 2-10

–

Determining the Serial Port Settings

page 2-11

Operating and Programming Guide

Chapter 2 Serial Interface Capabilities
About the RS-232C Serial Port(s)

About the RS-232C Serial Port(s)
The 58503B has only a rear-panel (PORT 1) RS-232C serial interface
port.
The 59551A has separate rear-panel (PORT 1) and front-panel
(PORT 2) RS-232C serial interface ports.
The rear-panel (PORT 1) RS-232C serial interface port is the only port
which can be used to upgrade the Receiver firmware; therefore, it is
referred to as the PRIMARY port. The 59551A’s front-panel (PORT 2)
RS-232C serial interface port is referred to as the SECONDARY port
because it cannot be used to upgrade the Receiver firmware. The
operation and configuration of these ports are described in the
following paragraphs. More information is provided in the sections
titled “Connecting a Computer or Modem” and “Configuring the
RS-232C Port(s)” in this chapter on page 2-5 and page 2-9,
respectively.
Either port allows you full communication with the Receiver. This can
be done by connecting any computer with an RS-232C serial interface
and suitable terminal emulation software, then sending the correct
commands for transmitting or retrieving data.

PORT 1 Rear-Panel RS-232C Serial Port
This 25-pin female subminiature D (DB-25) connector (PORT 1)
RS-232C Serial Interface Port is located on the rear panel.
The pins used for PORT 1 RS-232C communication are described in
Table 2-1.
NOTE

We reserve the right to impose signals on other pins; therefore, your
connection should be restricted to the pins described in Table 2-1.
Table 2-1. PORT 1 Rear-Panel RS-232C Serial Port Connections
*Pin
Number

Input/Output

Description

2

Output

Transmit Data (TxD). GPS Receiver output.

3

Input

Receive Data (RxD). GPS Receiver input.

7

_____

Signal Ground (SG)

Operating and Programming Guide

2-3

Chapter 2 Serial Interface Capabilities
About the RS-232C Serial Port(s)

Refer to the sections titled “Connecting a Computer or Modem” in this
chapter, on page 2-5, for wiring diagrams and more information on the
RS-232C interface cables.

PORT 2 Front-Panel RS-232C Serial Port
(59551A Only)
This 9-pin female subminiature D (DB-9) connector (PORT 2) RS-232C
Serial Interface Port is located on the front panel.
The pins used for PORT 2 RS-232C communication are described in
Table 2-2.
NOTE

We reserves the right to impose signals on other pins; therefore, your
connection should be restricted to the pins described in Table 2-2.
Table 2-2. PORT 2 Front-Panel RS-232C Serial Port Connections
(59551A Only)
*Pin
Number

Input/Output

Description

2

Input

Receive Data (RxD). GPS Receiver input.

3

Output

Transmit Data (TxD). GPS Receiver output.

5

_____

Signal Ground (SG)

Refer to the sections titled “Connecting a Computer or Modem” in this
chapter, on page 2-5, for wiring diagrams and more information on the
RS-232C interface cables.

2-4

Operating and Programming Guide

Chapter 2 Serial Interface Capabilities
Connecting a Computer or Modem

Connecting a Computer or Modem
To connect the GPS Receiver to a computer or modem, you must have
the proper interface cable. Most computers are DTE (Data Terminal
Equipment) devices. Since the Receiver is also a DTE device, you must
use a DTE-to-DTE interface cable when connecting to a computer.
These cables are also called “null-modem”, “modem-eliminator”, or
“crossover” cables.
Most modems are DCE (Digital Communication Equipment) devices;
thus, you must use a DTE-to-DCE interface cable.
The interface cable must also have the proper connector on each end
and the internal wiring must be correct. Connectors typically have
9 pins (DE-9 connector) or 25 pins (DB-25 connector) with a “male” or
“female” pin configuration. A male connector has pins inside the
connector shell and a female connector has holes inside the connector
shell.
To simplify interface cable selections, the following sections
tells you which cables to use.

Operating and Programming Guide

2-5

Chapter 2 Serial Interface Capabilities
Connecting a Computer or Modem

To Connect the GPS Receiver to a PC or Modem Via
the Rear-Panel PORT 1
Connecting to the Personal Computer (PC)
Use an HP 24542G interface cable or equivalent to connect the
Receiver’s rear-panel PORT 1 DB-25 female connector to a PC as
shown in Figure 2-1. See “Making Your Own Cables” starting on
page 2-8.

GPS Receiver
(Rear view)
WARNING:

Computer

NO OPERATOR SERVICEABLE PARTS INSIDE, REFER SERVICING TO SERVICE TRAINED PERSONNEL.

OUTPUTS
1 pps Programmable Irig-B
TOD

Time Tag
1

INPUTS
Time Tag
2

ANTENNA

ALARM BITE
Time Tag
3

!
POWER

!
Port 1

129 VDC

!
FOR LABORATORY USE BY
QUALIFIED PERSONNEL
FOUR USAGE EN LABORATOIRE
PAR PERSONNEL QUALIFIE

SERIAL PLATE

48 VDC
129 VDC

!

WARNING:

FOR CONTINUED FIRE PROTECTION, USE SPECIFIED ~ LINE FUSE.

HP 24542G
or equivalent

Figure 2-1. Connecting the GPS Receiver to a PC or Laptop

Connecting to a Modem
Use an HP 40242M interface cable or equivalent to connect the
Receiver’s rear-panel PORT 1 DB-25 female connector to a modem,
which is a DCE (Digital Communication Equipment) device, as shown
in Figure 2-2. See “Making Your Own Cables” starting on page 2-8.

2-6

Operating and Programming Guide

Chapter 2 Serial Interface Capabilities
Connecting a Computer or Modem

GPS Receiver
(Rear view)
WARNING:

NO OPERATOR SERVICEABLE PARTS INSIDE, REFER SERVICING TO SERVICE TRAINED PERSONNEL.

OUTPUTS
1 pps Programmable Irig-B
TOD

Time Tag
1

INPUTS
Time Tag
2

ANTENNA

ALARM BITE
Time Tag
3

!
POWER

!
Port 1

129 VDC

!
FOR LABORATORY USE BY
QUALIFIED PERSONNEL
FOUR USAGE EN LABORATOIRE
PAR PERSONNEL QUALIFIE

SERIAL PLATE

48 VDC
129 VDC

!

WARNING:

FOR CONTINUED FIRE PROTECTION, USE SPECIFIED ~ LINE FUSE.

HP 40242M
or equivalent

Modem set to
Auto-Answer

Telephone
Line

Figure 2-2 Connecting the GPS Receiver to a Modem

Operating and Programming Guide

2-7

Chapter 2 Serial Interface Capabilities
Connecting a Computer or Modem

Making Your Own Cables
If you choose to make your own cable, see Figure Figure 2-3 and
Figure Figure 2-4.
Figure Figure 2-3 illustrates how to make a DE-9S-to-DE-9P, DTEto-DCE interface cable that can replace the cable and adapter
combination of the HP 24542U cable and the HP 5181-6639 adapter for
use with PORT 2 of the 59551A.

Data
Terminal
Equipment
PC
RS-232C (9-pin)
PC input
PC output

RX
TX
GND

DE-9P
Male

DE-9S-to-DE-9P
(DTE-to-DCE) Interface Cable
1
2
3
4
5
6
7
8
9

1
2
3
4
5
6
7
8
9

DE-9S
Female

DE-9P
Male

Data
Communications
Equipment
59551A PORT 2
RS-232C (9-pin)
RX
TX

Instrument input
Instrument output

GND

DE-9S
Female

Figure 2-3 DE-9S-to-DE-9P (DTE-to-DCE) Serial Interface Connection
to PORT 2
Figure Figure 2-4 illustrates how to make a DE-9S-to-DB-25P,
DTE-to-DTE interface cable that can replace the HP 24542G cable
(25-pin male to 9-pin female connectors) for use with PORT 1.
Data
Terminal
Equipment
PC
RS-232C (9-pin)
PC input
PC output

RX
TX
GND

Data
Terminal
Equipment
PORT 1
RS-232C (25-pin)

DE-9S-to-DB-25P
(DTE-to-DTE)
Interface cable

1
2
3
4
5
6
7
8
9

DE-9P DE-9S
Male Female

1
2
3
4
5
6
7
8
20
22
DB-25P
Male

TX
RX

Instrument output
Instrument input

GND

DB-25S
Female

Figure 2-4 DE-9S-to-DB-25P (DTE-to-DTE) Serial Interface
Connection to PORT 1
2-8

Operating and Programming Guide

Chapter 2 Serial Interface Capabilities
Configuring the RS-232C Port(s)

Configuring the RS-232C Port(s)
The 59551A has separate rear-panel (PORT 1) and front-panel
(PORT 2) RS-232C serial interface ports.
The 58503B has one RS-232C serial interface port (PORT 1) on the
rear panel. Note: PORT 1 of the 58503B and PORT 2 of the 59551A
have the same configuration capabilities as indicated in Table 2-4.
Software pacing, baud rate, parity, data bits, and stop bits parameters
for each port are user-selectable and independent of the configuration
of the other.
Table 2-3 and Table 2-4 list the configuration factory-default values for
PORT 1 and PORT 2.
Table 2-3. Factory-Default Values for PORT 1 of the 59551A
Parameter

Default

Possible Choices

Software Pacing

NONE

XON or NONE

Baud Rate

9600

1200, 2400, 9600, or 19200

Parity

NONE

EVEN, ODD, or NONE

Data Bits

8

7 or 8

Stop Bits

1

1 or 2

Full Duplex

ON

ON or OFF

Table 2-4. Factory-Default Values for PORT 1 or the 58503B and
PORT 2 of the 59551A
Parameter

Default

Possible Choices

Software Pacing

NONE

XON or NONE

Baud Rate

9600

1200, 2400, 9600, or 19200

Parity

NONE

EVEN, ODD, or NONE

Data Bits

8

Fixed at 7 when parity is even or odd.
Fixed at 8 when parity is none.

Stop Bits

1

Fixed (no choices available)

Full Duplex

ON

ON or OFF

Procedures for configuring the RS-232C ports are provided in the
following paragraphs.

Operating and Programming Guide

2-9

Chapter 2 Serial Interface Capabilities
Configuring the RS-232C Port(s)

Making Changes to the Serial Port Settings
(If Needed)
CAUTION

If you change the serial port settings, your changes will be
stored in the Receiver. Cycling power will not reset to factory
defaults. Therefore, if you make a change, it is recommended
that you record the settings and keep the record with the
Receiver.
If you need to change the serial port settings, for example, to set
up for a different computer, use the guidelines given in this
section.
Serial port settings are changed by issuing commands.
It is recommended that you issue a single compound command which
simultaneously sets all the serial port parameters. Then connect the
other computer and begin using the instrument with the new settings.

NOTE

If you choose to set parameters one at a time, you will make the
procedure more difficult. That is, with each change, the instrument
will be updated, but your computer will retain its original settings.
At each step, you will have stopped serial communications and be
forced to modify your PC settings to match the Receiver in order to
continue. It is recommended that you make all changes in a single
compound command, verify the changes, and record all parameters.

Configuring PORT 1 of the 59551A
Complete configuration of PORT 1 of the 59551A requires that you set
five parameters. The command line sent in the following example
would set the RS-232C port pacing to XON, baud rate to 2400, parity to
EVEN, data bits to 7, and stop bits to 2. This command line must be
transmitted on PORT 1.
SYST:COMM:SER:PACE XON; BAUD 2400; PARITY EVEN; BITS 7; SBITS 2

Configuring PORT 1 of the 58503B and PORT 2 of the
59551A
Complete configuration of PORT 1 (58503B) and PORT 2 (59551A)
require that you set three parameters. The command line sent in the
following example would set the RS-232C port pacing to XON, baud
rate to 2400, and parity to EVEN. This command line must be
transmitted on PORT 1 or PORT 2.
SYST:COMM:SER2:PACE XON; BAUD 2400; PARITY EVEN

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Chapter 2 Serial Interface Capabilities
Configuring the RS-232C Port(s)

Determining the Serial Port Settings
Standard 58503B and 59551A
If you connect your PC, press Return, and do not get a scpi> prompt
back from the Receiver, your Receiver’s serial communication settings
may have been modified. You need to systematically step through the
data communication settings on your PC until your PC matches the
Receiver. The Receiver cannot communicate its settings until this
process is complete.
Iterate until you are able to verify that settings on your PC match the
Receiver.
When you are successful, you will have restored full RS-232C
communications, enabling you to query the Receiver’s communication
settings. Once you establish communications with one serial port, you
can query the Receiver for settings of either port.
Issue the following queries to either serial port to verify PORT 1’s
configuration.
SYST:COMM:SER:PACE?
SYST:COMM:SER:BAUD?
SYST:COMM:SER:PARITY?
SYST:COMM:SER:BITS?
SYST:COMM:SER:SBITS?

Issue the following queries to either serial port to verify PORT 2’s
configuration.
SYST:COMM:SER2:PACE?
SYST:COMM:SER2:BAUD?
SYST:COMM:SER2:PARITY?
SYST:COMM:SER2:BITS?
SYST:COMM:SER2:SBITS?

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Configuring the RS-232C Port(s)

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3

Visual User Interface
Using the Receiver Status Screen

Chapter 3 Visual User Interface
Chapter Contents

Chapter Contents
This chapter provides a tutorial section on how to use the Receiver
Status Screen, a comprehensive reference information section, and an
illustrated foldout of the Receiver Status Screen, which is a
comprehensive summary of key operation conditions and settings.
This chapter is organized as follows:
•

Using and Reading the Visual User Interface (the
Receiver Status Screen)

page 3-3

– Tutorial on Using the Status Screen to Interface With
the Receiver
page 3-3
•

•

3-2

– Demonstration of Holdover Operation

page 3-8

Receiver Status Screen Data

page 3-11

– SYNCHRONIZATION Section of the Status Screen

page 3-12

– ACQUISITION Section of the Status Screen

page 3-14

– HEALTH MONITOR Section of the Screen

page 3-18

The Receiver Status Screen at a Glance (foldout)

page 3-20

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Chapter 3 Visual User Interface
Using and Reading the Visual User Interface (the Receiver Status
Screen)

Using and Reading the Visual User
Interface (the Receiver Status Screen)
The combination of the PC and the GPS Receiver yields a visual user
interface called the Receiver Status Screen that lets you see what the
Receiver is doing and how it is progressing towards tracking satellites
to eventually lock to the GPS signal.
When connected to a properly configured PC, the Receiver Status
Screen can be accessed. There are two ways to access and use the
Receiver Status Screen:
•

By installing a commercially available terminal emulation
program, connecting the Receiver to a PC via the PORT 1 port, and
manually sending the :SYSTEM:STATUS? query. (Refer to Chapter 1,
“Getting Started,” in 58503B/59551A Getting Started Guide.)

•

By installing and operating the SatStat program, which
automatically generates continual status screen updates, and
connecting the Receiver to a PC via PORT 1. (Refer to the sections
titled “Installing the Automated SatStat Program for Continual
Status Updates” and “Operating the Automated SatStat Program”
in Chapter 1, “Getting Started,” of the 58503B/59551A Getting
Started Guide for details on installation and operation.)

The following tutorial demonstrates how you can use the Receiver
Status Screen to observe Receiver operation. The tutorial uses the
manual (:SYSTEM:STATUS?) method.

Tutorial on Using the Status Screen to Interface With
the Receiver
Type :SYSTEM:STATUS? at the scpi> prompt.
An initial power-up screen is displayed, which is similar to the
demonstration screen shown in Figure 3-1. The first data that you
should look at is in the SYNCHRONIZATION area of the screen. It is
telling you that it is in the Power-up state as indicated by the >>
marker. That is, the Receiver has just been put on line.

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Chapter 3 Visual User Interface
Using and Reading the Visual User Interface (the Receiver Status
Screen)

---------------------------- Receiver Status ---------------------------SYNCHRONIZATION ......................................... [ Outputs Invalid ]
Reference Outputs
SmartClock Mode
Locked
TFOM
9
FFOM
3
Recovery
1PPS TI -Holdover
HOLD THR 1.000 us
>> Power-up:GPS acquisition
Holdover Uncertainty
Predict -ACQUISITION ............................................. [GPS 1PPS Invalid]
Not Tracking: 6
Tracking: 0
Time
PRN El Az
UTC
12:00:00[?] 01 Jan 1996
*1 -- --GPS 1PPS Invalid: not tracking
*6 -- --ANT DLY 0 ns
*9 -- --Position
*14 -- --MODE
Survey: 0% complete
*22 -- --Suspended:track <4 sats
*24 -- --INIT LAT N
0:00:00.000
INIT LON W
0:00:00.000
INIT HGT
0 m (GPS)
ELEV MASK 10 deg *attempting to track
HEALTH MONITOR ...................................................... [ OK ]
Self Test: OK Int Pwr: OK
Oven Pwr: OK
OCXO: OK
EFC: OK
GPS Rcv: OK

Figure 3-1. Receiver Status Screen at Powerup
The ACQUISITION area of the screen is telling you that no satellites
have been tracked. The identification numbers of several satellites
appear in the Not Tracking column. The asterisk next to the satellite
identification number, or pseudorandom noise code (PRN), indicates
the Receiver is attempting to track it.
The current time and date are shown in the Time quadrant of the
ACQUISITION area. The default power-up setting, indicated by [?], is
corrected when the first satellite is tracked. Since the Receiver is not
tracking any satellites, the GPS 1 PPS reference signal is invalid.
An accurate position is necessary to derive precise time from GPS. The
Position quadrant indicates that the Receiver is in survey mode, which
uses GPS to determine the position of the GPS antenna. This process
has not yet started, since position calculations can be performed only
while tracking four or more satellites. INIT LAT, INIT LON, and INIT
HGT are the initial estimate of the true position. These coordinates are
refined by the survey process. The Receiver uses this position and the
time-of-day to select satellites to track. Therefore, you can reduce
satellite acquisition time by specifying a close approximation of
position and time.
Now, let’s send the :SYSTEM:STATUS? query again to see what kind of
progress the Receiver has made.
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Chapter 3 Visual User Interface
Using and Reading the Visual User Interface (the Receiver Status
Screen)
You can now see that the Receiver is tracking several satellites as
shown in Figure 3-2. The process of acquiring and tracking satellites is
described in the following paragraphs.

---------------------------- Receiver Status ---------------------------SYNCHRONIZATION ........................... [ Outputs Valid/Reduced Accuracy ]
Reference Outputs
SmartClock Mode
TFOM
6
FFOM
1
>> Locked to GPS: stabilizing frequency
Recovery
1PPS TI +71 ns relative to GPS
Holdover
HOLD THR 1.000 us
Power-up
Holdover Uncertainty
Predict -ACQUISITION ...............................................[GPS 1PPS Valid]
Not Tracking: 4
Tracking: 5
Time
PRN El Az C/N PRN El Az
UTC
17:56:44
31 Jan 1996
2 70 337
49
9 11 292
GPS 1PPS Synchronized to UTC
7 46 188
48
16 24 243
ANT DLY 0 ns
15 33 82
38 *26 Acq..
Position
19 28 113
36
31 -- --MODE
Survey: 1.2%
complete
22 65 91
49
AVG LAT N 37:19:34.746
AVG LON W 121:59:50.502
AVG HGT
+34.14 m (GPS)
ELEV MASK 10 deg *attempting to track
HEALTH MONITOR ...................................................... [ OK ]
Self Test: OK Int Pwr: OK Oven Pwr: OK
OCXO: OK
EFC: OK
GPS Rcv: OK

Figure 3-2. Receiver Status Screen Displaying Initial Satellite
Acquisition
An asterisk (*) next to the PRN of a satellite in the Not Tracking
column indicates the Receiver is attempting to track it. The elevation
(El) and azimuth (Az) angles of the satellite are indicated. Acq . or
Acq .. tell you that the Receiver is attempting to track that satellite.
One dot after the Acq indicator shows that the Receiver is attempting
to acquire its signal, and two dots indicate impending lock. Eventually,
you will see the satellite move to the Tracking column, which shows
the satellite PRN, the elevation angle of the satellite in the sky (90°
being zenith), the azimuth angle (number of degrees bearing from true
north), and the carrier-to-noise ratio (C/N). A good carrier-to-noise
ratio is a number above 35, which would be efficient for the Receiver to
operate. Numbers below 35, suggest intermittent tracking of the
satellite or no tracking; check your antenna system should this be the
case.
As indicated by the demonstration screen in Figure 3-2, the Receiver is
now surveying for position. It is tracking four satellites which is the
minimum number that must be tracked to determine postion. As you
can see, the Position MODE line indicates survey is 1.2% complete. A
complete survey would take two hours during which four satellites or
more are continuously tracked.
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Chapter 3 Visual User Interface
Using and Reading the Visual User Interface (the Receiver Status
Screen)
Also, you can see the initial (estimated) position has been replaced
with a computed position, which the Receiver continuous to refine until
it gets a very accurate position. The status screen indicates that a
computed position is being used by displaying the averaged latitude,
and longitude height (AVG LAT, AVG LON, and AVG HGT).
If the position were not precise, GPS timing information would be
inaccurate by an amount corresponding to the error in the computed
position. An error in the computed position of the antenna translates
into an error in the derived time and will compromise the Receiver’s
ability to be a timing source.
Let’s consider a case where four satellites are not visible at powerup
because of a poor antenna location, such as an “urban canyon” (located
between tall city buildings). If accurate position is known from a
Geodetic survey of that site, it can be programmed with the position
command, thereby bypassing the survey operation. This is useful when
four satellites cannot be tracked for an extended period of time.
Let’s send the :SYSTEM:STATUS? query again to observe the current
status of the Receiver.
The updated demonstration status screen in Figure 3-3 indicates that
the position survey is now 5.4% complete. Thus, the survey task is
beginning to iterate toward an accurate position. In the Time
quadrant, the UTC time is now correct. The date is correct, and the
GPS reference signal is synchronized to UTC.

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Chapter 3 Visual User Interface
Using and Reading the Visual User Interface (the Receiver Status
Screen)

---------------------------- Receiver Status ---------------------------SYNCHRONIZATION ............................[ Outputs Valid/Reduced Accuracy ]
Reference Outputs
SmartClock Mode
4
1
TFOM
FFOM
>> Locked to GPS: stabilizing frequency
Recovery
1PPS TI +20 ns relative to GPS
Holdover
HOLD THR 1.000 us
Power-up
Holdrover Uncertainty
Predict 432.0 us/initial 24 hrs
ACQUISITION ............................................... [GPS 1PPS Valid]
Not Tracking: 1
Tracking: 6
Time
PRN El Az C/N PRN El Az
UTC
2 70 301
40
16 13 258
18:47:07
31 Jan 1996
GPS 1PPS Synchronized to UTC
7 35 186
38
19 40 102
38
ANT DLY 0 ns
Position
22 71 60
39
Survey: 5.4%
complete
MODE
26 19 317
36
31 16 41
35
AVG LAT N 37:19:34.937
AVG LON W 121:59:50.457
+67.94 m (GPS)
AVG HGT
ELEV MASK 10 deg
HEALTH MONITOR ...................................................... [ OK ]
Self Test: OK Int Pwr: OK
Oven Pwr: OK
OCXO: OK
EFC: OK
GPS Rcv: OK

Figure 3-3. Receiver Status Screen Displaying Progress Towards
Steady-State Operation
In the SYNCHRONIZATION area, the >> marker is pointed at the
Locked to GPS line, indicating that the Receiver is locked to GPS and
stabilizing the frequency of its oscillator. This means that the Receiver
has phase-locked its oscillator to the 1 PPS reference signal provided
by GPS, but it is not at its final, or most stable, state. The Receiver is
locked and the front-panel GPS Lock LED is illuminated.
For users without the command interface (PC/Terminal emulator
connected to the Receiver), the illuminated GPS Lock LED is probably
the first indication that after powerup that the Receiver is moving
towards a stable state.
With the command interface and status screen, you can get more
detailed information. For example, you can read the reference outputs
quality indicators in the Reference Outputs area of the status screen.
These are the Time Figure of Merit (TFOM) and Frequency Figure of
Merit (FFOM) indicators. As shown in Figure 3-3, the TFOM is 4 and
the FFOM is 1. These values will eventually decrease towards the
ultimate values that represent steady-state performance. Refer to the
subsection titled ““Reference Outputs” on page 3-13 in this chapter for
more information about TFOM and FFOM.
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Chapter 3 Visual User Interface
Using and Reading the Visual User Interface (the Receiver Status
Screen)
Also indicated is a prediction of the accuracy of the Receiver should it
go into holdover operation.

Demonstration of Holdover Operation
CAUTION

The Receiver typically reaches stable state 24 to 72 hours after
powerup, and it will learn best if its experiences no holdover in the first
24 hours. Therefore, the holdover demonstration in the following
paragraphs will compromise the Receiver’s ability to learn the
characteristics of its internal reference oscillator. For the purpose of
education only, you will be shown how to initiate a holdover.
A user should never initiate holdover during the first 24 hours while
the Receiver is learning its internal oscillator characteristics. The
Receiver should maintain GPS lock during this time because it is using
the GPS signal to discipline the oscillator. It will learn what the
oscillator drift characteristics are relative to the GPS signal. It will
learn how the oscillator ages, and the software will learn how to
compensate for that aging.
Thus, it is recommended that the Receiver is always kept locked to
GPS during the first 24 hours.

For demonstration purposes, and since the Receiver has been powered
up for a while, let’s put the Receiver into holdover by simply removing
the antenna connection. (Note that holdover also can be manually
initiated by sending the SYNCHRONIZATION:HOLDOVER:INITIATE
command; however, for this demonstration, disconnect the antenna
cable.) The following will occur after a verification delay:
•

The front-panel Holdover LED will illuminate, and

•

after sending the :SYSTEM:STATUS? query again, a screen similar to
Figure 3-4 should appear.

Let’s send the :SYSTEM:STATUS? query. Figure 3-4 should appear.

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Chapter 3 Visual User Interface
Using and Reading the Visual User Interface (the Receiver Status
Screen)

---------------------------- Receiver Status ---------------------------SYNCHRONIZATION ........................... [ Outputs Valid/Reduced Accuracy ]
Reference Outputs
SmartClock Mode
TFOM
FFOM
3
2
Locked to GPS
Recovery
1PPS TI ->> Holdover: GPS 1PPS invalid
HOLD THR 1.000 us
Power-up
Holdover Uncertainty
Predict 432.0 us/initial 24 hrs
Holdover Duration: 0m 14s
Present 1.0 us
ACQUISITION ............................................. [GPS 1PPS Invalid]
Not Tracking: 7
Tracking: 0
Time
PRN El Az PRN El Az
UTC
20:56:14
31 Jan 1996
*2
71 316 *31 12 29
GPS 1PPS Inaccurate: not tracking
*7
41 186
ANT DLY 0 ns
15 11 86
Position
*19 35 107
MODE
Survey: 71.1% complete
*22 68 78
*26 23 314
LAT
N 37:19:32.472
LON
W 121:59:51.784
HGT
+42.19 m (GPS)
ELEV MASK 10 deg *attempting to track
HEALTH MONITOR ...................................................... [ OK ]
Self Test: OK Int Pwr: OK Oven Pwr: OK
OCXO: OK
EFC: OK
GPS Rcv: OK

Figure 3-4. Receiver Status Screen Displaying Holdover Operation
In the SYNCHRONIZATION area, you can see that the Receiver has
gone into holdover as indicated by >> marker that is pointing at the
Holdover line. The status screen indicates that the reason the Receiver
is in holdover is because the GPS 1 PPS reference signal is invalid.
You would expect this since the antenna has been disconnected.
The status screen shows loss of the GPS signal. As you can see on the
screen, all of the satellites in the Tracking column moved into the Not
Tracking column.
The status screen in Figure 3-4 shows that the Receiver has been in
holdover operation for 14 seconds.
If the Receiver SmartClock had had enough time to learn the internal
oscillator characteristics, the Receiver Status Screen would show that
the Receiver went into holdover, and the Receiver’s outputs were
maintained during holdover by the SmartClock.

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Chapter 3 Visual User Interface
Using and Reading the Visual User Interface (the Receiver Status
Screen)
When the GPS antenna is re-connected and the GPS signal has been
re-acquired, the Receiver has the ability to recover from holdover by
itself. The SYNCHRONIZATION area of the screen will show the >>
marker pointing at the Recovery line (and then eventually at the
Locked to GPS line), the GPS Lock LED will illuminate, and the screen
will look similar toFigure 3-5.

---------------------------- Receiver Status ---------------------------SYNCHRONIZATION ............................[ Outputs Valid/Reduced Accuracy ]
Reference Outputs
SmartClock Mode
3
1
TFOM
FFOM
>> Locked to GPS: Stabilizing frequency
Recovery
1PPS TI +10.6 ns relative to GPS
Holdover
HOLD THR 1.000 us
Power-up
Holdover Uncertainty
Predict 432.0 us/initial 24 hrs
ACQUISITION ............................................... [GPS 1PPS Valid]
Not Tracking: 0
Tracking: 6
Time
PRN El Az C/N
UTC
20:59:28
31 Jan 1996
2 71 317
40
GPS 1PPS Synchronized to UTC
7 34 185
38
ANT DLY 0 ns
19 41 101
37
Position
22 67 80
40
MODE
Survey: 71.4% complete
26 24 312
37
31 12 27
36
LAT
N 37:19:32.486
LON
W 121:59:52.082
HGT
+40.06 m (GPS)
ELEV MASK 10 deg
HEALTH MONITOR ...................................................... [ OK ]
Self Test: OK Int Pwr: OK Oven Pwr: OK
OCXO: OK
EFC: OK
GPS Rcv: OK

Figure 3-5. Receiver Status Screen Following Recovery from
Holdover Operation
You can see the Receiver has recovered from holdover almost
immediately and it has returned to locked operation.

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Chapter 3 Visual User Interface
Receiver Status Screen Data

Receiver Status Screen Data
This section defines the data displayed in the Receiver Status Screen,
shown in Figure 3-6.
---------------------------- Receiver Status ---------------------------SYNCHRONIZATION .......................................... [ Outputs Valid ]
Reference Outputs
SmartClock Mode
>> Locked to GPS
TFOM
3
FFOM
0
Recovery
1PPS TI +7.2 ns relative to GPS
Holdover
HOLD THR 1.000 us
Power-up
Holdover Uncertainty
Predict 49.0 us/initial 24 hrs
ACQUISITION ................................................[GPS 1PPS Valid]
Not Tracking: 1
Tracking: 6
Time
PRN El Az C/N
PRN El Az
+1 leap second pending
UTC
2
49 243
49
14 11 82
23:59:59
31 Dec 1995
GPS 1PPS Synchronized to UTC
16 24 282
46
120 ns
ANT DLY
47
18 38 154
Position
49
19 65 52
Survey: 17.5% complete
MODE
49
27 62 327
47
31 34 61
AVG LAT N 37:19:32.264
AVG LON W 121:59:52.112
+41.86 m (GPS)
AVG HGT
ELEV MASK 10 deg
HEALTH MONITOR ...................................................... [ OK ]
Self Test: OK Int Pwr: OK Oven Pwr: OK
OCXO: OK
EFC: OK
GPS Rcv: OK

Figure 3-6. Sample Status Screen
The status screen has three major sections:
•

SYNCHRONIZATION

•

ACQUISITION

•

HEALTH MONITOR

The SYNCHRONIZATION section of the status screen shows how the
GPS Receiver’s SmartClock technology is progressing towards its
objective, which is to synchronize the Receiver’s oscillator to the 1 PPS
reference signal produced by the Receiver’s internal GPS Engine.
The ACQUISITION section of the status screen shows how the
Receiver’s internal GPS Engine is progressing towards its objective,
which is to produce an accurate internal 1 PPS reference signal. It does
so through tracking GPS satellites.
The HEALTH MONITOR section of the status screen summarizes the
overall health of the product.

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Chapter 3 Visual User Interface
Receiver Status Screen Data

SYNCHRONIZATION Section of the Status Screen
SYNCHRONIZATION Summary Line
The SYNCHRONIZATION line in the screen summarizes the
SmartClock Status and Reference Outputs. One of three
SYNCHRONIZATION messages is shown:
Outputs Invalid
Outputs Valid/
Reduced Accuracy
Outputs Valid

while the Receiver (unit) is warming up,
while the unit is in holdover or is locked but has
not achieved steady-state operation, or
while the unit is in steady-state operation.

SmartClock Mode
The SmartClock Mode area of the screen shows the four operating
modes:
•

Locked to GPS

•

Recovery

•

Holdover

•

Power-up

As shown in the sample status screen in Figure 3-6, a >> symbol
indicates the current operating mode.
Locked to GPS indicates that the Receiver is locked to GPS. The
front-panel GPS Lock LED will be illuminated.
When stabilizing frequency ... is shown, the time output (1 PPS) signal is
locked and can be used, but the frequency outputs (10 MHz) are not at
their final or most stable state.
Recovery indicates that the Receiver is actively working to become
locked to GPS. All conditions needed to proceed towards a lock have
been met. Expect an eventual spontaneous transition to a lock (unless
changing external conditions prevent this, such as loss of tracked
satellites.)
Holdover indicates that the Receiver is waiting for conditions that are
needed to allow the process of recovery from holdover to begin. Once
these conditions are met, the Receiver will transition on its own to the
recovery mode.
When the GPS 1PPS CLK invalid message follows the Holdover label,
the internal GPS 1 PPS reference signal is inaccurate.
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Chapter 3 Visual User Interface
Receiver Status Screen Data

When the manually initiated message follows the Holdover label, the
Receiver has been placed in holdover by the user. An explicit command
is required to initiate an exit from manual holdover.
When the 1 PPS TI exceeds hold threshold message follows the
Holdover label, the phase difference between the 1 PPS time output
signal and the internal GPS 1 PPS reference signal has exceeded the
user-entered holdover threshold value.
When the internal hardware problem message follows the Holdover
label, a measurement hardware error exists.
The Holdover Duration message indicates the duration that the Receiver
has been operating in holdover (and recovery). Thus, this message
gives you an assessment of the quality of the outputs. The longer the
Receiver is in holdover the more degraded the outputs become.
Power-up indicates that the Receiver hasn’t yet achieved GPS lock or
acquired satellites since it has been powered up. The Receiver is
measuring the internal reference oscillator’s frequency and adjusting it
to 10 MHz during this power-up period. Other queries can provide
insight as to the cause if the Receiver is remaining in powerup longer
than expected.

Reference Outputs
TFOM (Time Figure of Merit) indicates the accuracy of the Receiver’s
internal 1 PPS signal. A low TFOM value indicates a more accurate
signal. In the sample screen of Figure 3-6, a value of 3 is displayed,
meaning that the Time Error ranges from 100 to 1000 nanoseconds.
The following table lists the TFOM values that could be displayed and
the corresponding Time Error.

TFOM Value

Time Error
(in nanoseconds)

TFOM Value

Time Error
(in nanoseconds)

*0

less than 1

5

104 – 105

*1

1 – 10

6

105 – 106

*2

10 – 100

7

106 – 107

3

100 – 1000

8

107 – 108

4

103 – 104

9

greater than 108

*The TFOM values 0, 1, and 2 are not presently used in the Receiver. The Receiver will display
TFOM values ranging from 9 to 3, which is consistent with the specified accuracies of each product.

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Chapter 3 Visual User Interface
Receiver Status Screen Data

FFOM (Frequency Figure of Merit) indicates the stability of the
Receiver’s internal 10 MHz signal. The 10 MHz signal is controlled by
the SmartClock’s Phase-Locked Loop (PLL). Thus, the FFOM value is
determined by monitoring the status of the PLL.
In the sample screen of Figure 3-6, the 0 indicates that the
SmartClock’s PLL is stabilized. The following table lists and defines
the FFOM values that could be displayed.
FFOM Value

Definition

0

PLL stabilized — internal 10 MHz signal within
specification.

1

PLL stabilizing

2

PLL unlocked (holdover) — Initially the 10 MHz signal
will be within specifications. However, when in holdover,
the 10 MHz signal will eventually drift out of
specification.

3

PLL unlocked (not in holdover) — Do not use the output.

1PPS TI indicates the difference (timing shift) between the SmartClock
1 PPS and the internal GPS 1 PPS signals.
HOLD THR (holdover threshold) displays the user-entered time error
value.

ACQUISITION Section of the Status Screen
ACQUISITION Line
The ACQUISITION line in the screen summarizes the state of the
internal GPS Engine as indicated by the Tracking, Not Tracking, and
Position areas of the screen.
If the Receiver Engine was considered to be synchronized to the GPS
signal, the [GPS 1 PPS Valid] message will appear at the end of the
ACQUISITION line. If the Receiver has not yet synchronized to GPS,
the [GPS 1 PPS CLK Invalid] message will be displayed.

Tracking, Not Tracking
The Tracking table indicates the number of satellites the Receiver is
tracking.
The Not Tracking table indicates satellites predicted to be visible that
are not tracked, and all of the satellites that are assigned to a GPS
Engine channel but are not currently tracked.
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Receiver Status Screen Data

Health and status indicators in the tables are defined as follows:
PRN

indicates the pseudorandom noise code assigned to the
satellite.

El

indicates the predicted elevation angle, from a range of 0
to 90°. The predicted elevation is derived from the
almanac.

--

indicates that the elevation angle is unknown (the
almanac did not provide this data).

Az

indicates the predicted azimuth angle, from a range of 0
to 359°. The predicted azimuth angle is referenced to true
north, and is derived from the almanac.

---

indicates that the azimuth angle is unknown (the
almanac did not provide this data).

C/N

indicates the carrier-to-noise ratio of the received the
signal, from a range of 26 to 55. A ratio below 35 is a
weak signal that may not be acquired by the Receiver.

(58503B)

or
SS
(59551A)

indicates the strength of the signal, from a range of 0 to
255. A signal strength of 20 to 30 is a weak signal that
may not be acquired by the Receiver.

The health and status indicators in the Not Tracking table are
described as follows:
Ignore

indicates that the user has chosen to exclude this
satellite from a list of satellites available for tracking.

Not OK

indicates GPS has reported that this satellite is
unhealthy.

Acq

indicates the unit is attempting to acquire the satellite
signal.

Acq .

indicates the unit is reading timing information from
the satellite.

Acq . .

indicates the unit is reading satellite orbital
information.

ELEV MASK indicates the elevation mask angle in degrees. Satellites
at or above this elevation angle are considered for
tracking.
*attempting
to track

indicates that the Receiver is attempting to track a
satellite.

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Chapter 3 Visual User Interface
Receiver Status Screen Data

Time
When you first power up the unit the time and date that is stored in
the internal GPS Engine may not be the actual date. The actual time
and date will be valid after one satellite has been tracked by the
Receiver.
NOTE

There are two accurate ways to express time (GPS or UTC). GPS time
is offset from UTC time by the number of accumulated leap seconds
since midnight of January 6, 1980 UTC.

The Time area of the status screen provides three types of information:
Time, 1PPS CLK, and ANT DLY.
Time has four possible modes: GPS, UTC, LOCL GPS, and LOCAL.
GPS indicates current time and date collected from a satellite in GPS
Time.
LOCL GPS indicates GPS Time, offset for the local time zone.
UTC indicates current time and date collected from a satellite in UTC
time.
LOCAL indicates current time and date collected from a satellite offset
from UTC for the local time zone.
1PPS CLK can indicate several possible advisory messages. These
messages are:
Synchronized 1 PPS locked to GPS, referenced to GPS Time.
to GPS Time
Synchronized 1 PPS locked to GPS, referenced to UTC.
To UTC
Assessing
stability ...

applying hysteresis to locked 1 PPS signal.

Inaccurate,
not tracking

not tracking satellites.

Inaccurate,
in survey mode, but has not yet calculated a position.
inacc position
Absent or freq no 1PPS signal; or the internal GPS Engine is idle.
incorrect

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Chapter 3 Visual User Interface
Receiver Status Screen Data

ANT DLY (antenna delay) displays the user-entered value that is used
to compensate for the propagation delay of the antenna cable.

Position
Position area of the status screen provides four types of information:
MODE (hold or survey), LAT (latitude), LON (longitude), and HGT
(height).
MODE indicates whether the unit is set to Hold or Survey position
mode.
When Hold is displayed, the unit’s antenna position has been provided
by the user, or the average position has been found after completion of
survey.
If the unit is in the position Hold mode, the LAT, LON, and HGT “held”
position coordinates will be displayed.
If Survey: 57.3% complete is displayed, for example, the Receiver is
set to survey mode trying to determine the position of the antenna. The
% value indicates the progress of the surveying.
At the beginning of a survey (0% completion), the following “estimated”
position coordinates will be displayed:
INIT LAT indicates the estimated latitude (North or South) position of
the unit in degrees, minutes, and seconds.
INIT LON indicates the estimated longitude (East or West) position of
the unit in degrees, minutes, and seconds.
INIT HGT indicates estimated height of the unit’s antenna, in meters
above the GPS ellipsoid for 58503B (in meters above mean sea level,
MSL, for the 59551A).
Once survey starts, the following “averaged” position coordinates will
be displayed:
AVG LAT indicates the average latitude (North or South) position of the
unit in degrees, minutes, and seconds.
AVG LON indicates the average longitude (East or West) position of the
unit in degrees, minutes, and seconds.
AVG HGT indicates average height of the unit’s antenna, in meters
above the GPS ellipsoid for 58503B (in meters above mean sea level,
MSL, for the 59551A).

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Chapter 3 Visual User Interface
Receiver Status Screen Data

The possible advisory messages that can be displayed when position
mode is Survey are:
Suspended: track <4 sats
Suspended: poor geometry
Suspended: no track data

HEALTH MONITOR Section of the Screen
The HEALTH MONITOR section of the status screen reports errors or
failures of the key hardware functions. The OK summary message at
the end of the HEALTH MONITOR line indicates that no errors or
failures were detected. Error indicates that one or more hardware tests
failed.
For each hardware function, OK is reported when it is operating
normally; Err is displayed when a failure or an error is detected.
Hardware functions are monitored periodically, with the exception of
Self Test, which is performed at powerup or when requested.
The health and status indicators in the HEALTH MONITOR section
are described as follows:
Self Test

Last diagnostic check of the microprocessor system,
reference oscillator, satellite receiver, and power
supplies failed.

Int Pwr

Internal power supply voltage(s) exceeds tolerance.

Oven Pwr

Oscillator oven power supply voltage exceeds tolerance.

OCXO

Oscillator output failed.

EFC

Oscillator control voltage is at or near full-scale.

GPS Rcv

Satellite receiver communication failed, or GPS 1PPS
reference is absent.

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Receiver Status Screen Data

This Page Intentionally Left Blank.

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Chapter 3 Visual User Interface
The Receiver Status Screen at a Glance

The Receiver Status Screen at a Glance

3-20

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Chapter 3 Visual User Interface
The Receiver Status Screen at a Glance

The Receiver Status Screen at a Glance (cont’d)

Operating and Programming Guide

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Chapter 3 Visual User Interface
The Receiver Status Screen at a Glance

3-22

Operating and Programming Guide

4

Command Quick Reference

Chapter 4 Command Quick Reference
Chapter Contents

Chapter Contents
This chapter is a quick reference that summarizes the GPS Receiver
commands which allow you to operate and program the Receiver.
This chapter is organized as follows:
•

•

•

•

4-2

An Introduction to GPS Receiver Commands

page 4-4

–

SCPI Conformance Information

page 4-4

–

Command Syntax Conventions

page 4-4

–

Command Presentation

page 4-4

GPS Satellite Acquisition

page 4-5

–

Facilitating Initial Tracking

page 4-5

–

Establishing Position

page 4-5

–

Selecting Satellites

page 4-6

–

Compensating for Antenna Delay

page 4-6

–

Monitoring Acquisition

page 4-6

1 PPS Reference Synchronization

page 4-7

–

Monitoring 1 PPS Synchronization

page 4-7

–

Assessing 1 PPS Quality

page 4-7

–

Operating in Holdover

page 4-7

Operating Status

page 4-8

–

Receiver Operation at a Glance

page 4-8

–

Reading the Error Queue

page 4-8

–

Reading the Diagnostic Log

page 4-8

–

Monitoring Status/Alarm Conditions

page 4-8

–

Assessing Receiver Health

page 4-9

Operating and Programming Guide

Chapter 4 Command Quick Reference
Chapter Contents

•

System Time

page 4-10

–

Identifying Time of Next 1 PPS Reference Edge

page 4-10

–

Reading Current Time

page 4-10

–

Applying Local Time Zone Offset

page 4-10

–

Defining the 1 PPS Reference Edge (59551A Only)

page 4-10

–

Reading Leap Second Status

page 4-10

•

Programmable Pulse Output (59551A Only)

page 4-11

•

Event Time Stamping (59551A Only)

page 4-12

–

Defining the Time-stamped Edge

page 4-12

–

Clearing Time Stamp Memory

page 4-12

–

Reading Time Stamps

page 4-12

–

Processing Memory Overflow

page 4-12

Serial Interface Communication

page 4-13

–

Configuring I/O Port 1

page 4-13

–

Configuring I/O Port 2 (59551A Only)

page 4-13

–

Recovering the Last Query Response

page 4-13

•

•

Receiver Initialization

page 4-14

•

Receiver Identification/Upgrade

page 4-15

–

Reading Product Identification

page 4-15

–

Installing Firmware via I/O Port 1

page 4-15

•

Receiver Commands at a Glance (cont’d)/Status
Reporting System at a Glance (foldout)

Operating and Programming Guide

page 4-17

4-3

Chapter 4 Command Quick Reference
An Introduction to GPS Receiver Commands

An Introduction to GPS Receiver
Commands
SCPI Conformance Information
The SCPI commands used in the GPS Receiver are in conformance
with the SCPI Standard Version 1994.0.
Details of all the GPS Receiver commands can be found in Chapter 5,
“Command Reference,” of this guide.
Information on the SCPI commands format, syntax, parameter, and
response types is provided in Appendix B, “Command Syntax and
Style,” of this guide.

Command Syntax Conventions
POSition

NOTE

Means you MUST use either all the upper case letters or
the entire word. The lower case letters are optional.
For example, POS and POSITION are both valid.
However, POSI is not valid. (Note: POSition is used here
as an example, but this convention is true for all
command keywords.) In other words, the short form of
the keywords is shown in uppercase.

When you see quotation marks in the command’s parameter, you must
send the quotation marks with the command.

Command Presentation
The shaded commands listed in the following sections are the “basic”
(fundamental) or most commonly used commands. These commands
are essential for operating the Receiver; thus, a brief description of
each of these commands is included in this section. More complete
descriptions are provided in Chapter 5, “Command Reference.”
The non-shaded commands listed in this section are not fundamental
or not commonly used. These commands are used for one-time setup,
advanced, or specialized operation of the Receiver. Descriptions of
these commands are provided in Chapter 5 only.

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Operating and Programming Guide

Chapter 4 Command Quick Reference
GPS Satellite Acquisition

GPS Satellite Acquisition
The following commands are provided to facilitate initial GPS satellite
tracking, to establish accurate GPS antenna position, to select or ignore
satellites, to compensate for antenna cable delay, and to monitor the
acquisition.

Facilitating Initial Tracking
:GPS:INITial:DATE , , 
:GPS:INITial:POSition N or S, ,
,
,
E or W, ,
,
,

or

:GPS:INITial:TIME , , 

Establishing Position
:GPS:POSition

N or S, ,
,
,
E or W, ,
,
,

or

Specifies the position of the GPS antenna.
:GPS:POSition?
Returns the current average position of the GPS antenna.

:GPS:POSition:ACTual?
Returns the current instantaneous position of the GPS antenna.

:GPS:POSition LAST
:GPS:POSition SURVey
:GPS:POSition:HOLD:LAST?
:GPS:POSition:HOLD:STATe?
:GPS:POSition:SURVey:PROGress?
:GPS:POSition:SURVey:STATe ONCE
:GPS:POSition:SURVey:STATe?
:GPS:POSition:SURVey:STATe:POWerup ON or OFF
:GPS:POSition:SURVey:STATe:POWerup?

Basic command

Operating and Programming Guide

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Chapter 4 Command Quick Reference
GPS Satellite Acquisition

Selecting Satellites
 = IGNore or INCLude
:GPS:SATellite:TRACking:EMANgle 
Sets the GPS elevation mask angle value.

:GPS:SATellite:TRACking:EMANgle?
Returns the GPS elevation mask angle value.

:GPS:SATellite:TRACking:IGNore , ... , 

(59551A)

Sends list of satellites to ignore.

:GPS:SATellite:TRACking:IGNore?

(59551A)

Returns list of satellites to ignore.

:GPS:SATellite:TRACking:INCLude , ... , 
:GPS:SATellite:TRACking:INCLude?
:GPS:SATellite:TRACking::ALL
:GPS:SATellite:TRACking::COUNt?
:GPS:SATellite:TRACking::NONE
:GPS:SATellite:TRACking::STATe? 

(59551A)
(59551A)
(59551A)

Compensating for Antenna Delay
:GPS:REFerence:ADELay 
Sets the GPS antenna delay value in seconds.

:GPS:REFerence:ADELay?
Returns the GPS antenna delay value in seconds.

Monitoring Acquisition
:GPS:REFerence:VALid?
Indicates whether the date and time are valid (1 = valid).

:GPS:SATellite:TRACking?
Returns a list of all satellites being tracked.

:GPS:SATellite:VISible:PREDicted?
Returns the list of satellites (PRN) that the almanac predicts should be visible, given date, time, and
position.

:GPS:SATellite:TRACking:COUNt?
:GPS:SATellite:VISible:PREDicted:COUNt?

Basic command

4-6

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Chapter 4 Command Quick Reference
1 PPS Reference Synchronization

1 PPS Reference Synchronization
The following commands are provided to monitor the operating mode of the
reference oscillator, to determine the accuracy and stability of the reference
output signal(s), and to control the oscillator holdover process.

Monitoring 1 PPS Synchronization
:SYNChronization:STATe?
Returns the Receiver state.

:DIAGnostic:ROSCillator:EFControl:RELative?
:LED:GPSLock?
:LED:HOLDover?

Assessing 1 PPS Quality
:SYNChronization:FFOMerit?
Returns the Frequency Figure of Merit.

:SYNChronization:HOLDover:TUNCertainty:PREDicted?
Returns an estimate of the time error that can be expected for a one day holdover, given
the current state of SmartClock learning in the Receiver.

:SYNChronization:HOLDover:TUNCertainty:PRESent?
Returns the current time interval error at any time during holdover operation, given the
current state of SmartClock learning in the Receiver.

:SYNChronization:TFOMerit?
Returns the Time Figure of Merit.

:SYNChronization:TINTerval?
Returns the difference or timing shift between the SmartClock 1 PPS and the
GPS 1 PPS signals.

:SYNChronization:HOLDover:DURation?
:SYNChronization:HOLDover:DURation:THReshold 
:SYNChronization:HOLDover:DURation:THReshold?
:SYNChronization:HOLDover:DURation:THReshold:EXCeeded?

Operating in Holdover
Initiating Manual Holdover
:SYNChronization:HOLDover:INITiate

Recovering from Holdover
:SYNChronization:HOLDover:WAITing?
Returns prioritized reason why the Receiver is waiting to recover.

:SYNChronization:HOLDover:RECovery:INITiate
:SYNChronization:HOLDover:RECovery:LIMit:IGNore
:SYNChronization:IMMediate

Basic command

Operating and Programming Guide

4-7

Chapter 4 Command Quick Reference
Operating Status

Operating Status
The following commands are provided to obtain Receiver status information.
There are several ways to obtain Receiver status using commands.
For example, you can send a command to display the Receiver Status screen,
to read the error queue, and to read the diagnostic log. You can also send a
sequence of commands to read and control the status registers for alarm
generation.

Receiver Operation at a Glance
:SYSTem:STATus?
Outputs a fully formatted status screen.

:SYSTem:STATus:LENGth?

Reading the Error Queue
:SYSTem:ERRor?
Returns the oldest error in the Error Queue and removes that error from the queue (first in, first out).

Reading the Diagnostic Log
:DIAGnostic:LOG:CLEar
Clears the diagnostic log.

:DIAGnostic:LOG:READ:ALL?
Returns all of the most recent diagnostic log entries.

:DIAGnostic:LOG:CLEar 
:DIAGnostic:LOG:COUNt?
:DIAGnostic:LOG:READ?
:DIAGnostic:LOG:READ? 

Monitoring Status/Alarm Conditions
Clearing and Presetting Alarms
*CLS
Clears the event status registers and error queue.

:STATus:PRESet:ALARm

Reading and Qualifying Alarms
:LED:ALARm?
Returns status of front-panel Alarm LED.

*SRE 
*SRE?
*STB?

Basic command

4-8

Operating and Programming Guide

Chapter 4 Command Quick Reference
Operating Status

Reading and Qualifying Receiver Status
 = OPERation
 = QUEStionable
 = OPERation:HARDware
 = OPERation:HOLDover
 = OPERation:POWerup
:STATus::CONDition?
Returns the Condition Status Register value.

:STATus::EVENt?
Returns the Event Status Register value.

:STATus::ENABle 
:STATus::ENABle?
:STATus::NTRansition 
:STATus::NTRansition?
:STATus::PTRansition 
:STATus::PTRansition?

Reading and Qualifying Command Error Status
*ESE 
*ESE?
*ESR?

Reporting Questionable Status
:STATus:QUEStionable:CONDition:USER SET or CLEar
:STATus:QUEStionable:EVENt:USER PTR or NTR

Assessing Receiver Health
*TST?
Executes an internal selftest and reports the results.

:DIAGnostic:LIFetime:COUNt?
:DIAGnostic:TEST? ALL or DISPlay or PROCessor or RAM or EEPROM or UART or QSPI
or FPGA or INTerpolator or IREFerence or GPS or POWer
:DIAGnostic:TEST:RESult?

Basic command

Operating and Programming Guide

4-9

Chapter 4 Command Quick Reference
System Time

System Time
The following commands are provided to allow you to monitor and control the
system date and time. These commands allow you access to a very accurate
system clock that provides both date and time, to customize the clock for a local
time zone, to identify the exact time, to identify the accumulated time
difference (in seconds) between the GPS and UTC timelines, and to monitor
leap second occurrences.

Identifying Time of Next 1 PPS Reference Edge
R

:PTIMe:TCODe?
Returns timecode message 980 to 20 ms prior to 1 PPS of indicated time.

Reading Current Time
:PTIMe:DATE? or
:PTIMe:TIME?
or
:PTIMe:TIME:STRing?

:SYSTem:DATE?
:SYSTem:TIME?

Applying Local Time Zone Offset
:PTIMe:TZONe , 
Sets the time zone local time offset to provide an offset from UTC to serve as the basis for all
reported time.

:PTIMe:TZONe?
Returns the local time zone offset.

Defining the 1 PPS Reference Edge (59551A Only)
:PTIMe:PPS:EDGE RISing or FALLing
Selects the polarity of the 1 PPS on-time edge.

:PTIMe:PPS:EDGE?
Returns the polarity of the 1 PPS on-time edge.

Reading Leap Second Status
:PTIMe:LEAPsecond:ACCumulated?
Returns the leap second difference accumulated between GPS time and UTC time since the beginning
of GPS time. The time units are seconds.

:PTIMe:LEAPsecond:DATE?
:PTIMe:LEAPsecond:DURation?
:PTIMe:LEAPsecond:STATe?

Basic command
R: Accessible via rear-panel PORT 1.

4-10

Operating and Programming Guide

Chapter 4 Command Quick Reference
Programmable Pulse Output (59551A Only)

Programmable Pulse Output (59551A
Only)
The following commands are provided to allow you to operate and control the
programmable pulse output of the 59551A GPS Receiver. The pulse output,
which is programmable by the user, can either generate a stream of pulses at
a specified start time and repetition interval, or can produce a single pulse at
a specified time and then stop.

:PULSe:CONTinuous:PERiod 
Sets the interval between pulses in seconds.

:PULSe:CONTinuous:PERiod?
Returns the interval between pulses in seconds.

:PULSe:CONTinuous:STATe ON or OFF
Selects whether the Programmable Pulse output will be just one pulse or a sequence of pulses.

:PULSe:CONTinuous:STATe?
Identifies whether the Programmable Pulse output is set to output a single pulse or
sequence of pulses.

:PULSe:REFerence:EDGE RISing or FALLing
Selects the polarity of the Programmable Pulse on-time edge.

:PULSe:REFerence:EDGE?
Returns the polarity of the Programmable Pulse on-time edge.

:PULSe:STARt:DATE , , 
Sets the date when the individual pulse (or first pulse of the pulse sequence) is to be generated at the
Programmable Pulse output.

:PULSe:STARt:DATE?
Returns the date when the individual pulse (or first pulse of the pulse sequence) is generated at the
Programmable Pulse output.

:PULSe:STARt:TIME , , 
Sets the time when the individual pulse (or first pulse of the pulse sequence) is to be generated at the
Programmable Pulse output.

:PULSe:STARt:TIME?
Returns the time when the individual pulse (or first pulse of the pulse sequence) is generated at the
Programmable Pulse output.

Basic command

Operating and Programming Guide

4-11

Chapter 4 Command Quick Reference
Event Time Stamping (59551A Only)

Event Time Stamping (59551A Only)
The following commands are provided to allow you to time-tag and record
events such as power surges and power outages. The time tagging input
feature allows you to use the Receiver with equipment which produce a TTL
edge when some important event happens in the base station. The Receiver has
three time tagging inputs which record the time of occurrence of TTL edge(s).

Defining the Time-stamped Edge
 = 1 or 2 or 3
:SENSe:TSTamp:EDGE RISing or FALLing
Selects the polarity of the edges the Receiver will timestamp.

:SENSe:TSTamp:EDGE?
Returns the polarity of the edges the Receiver will timestamp.

Clearing Time Stamp Memory
:SENSe:DATA:CLEar
Clears the data in the measurement buffer for all Time Tag inputs.

:SENSe:DATA:CLEar "TSTamp 1" or "TSTamp 2" or "TSTamp 3"

Reading Time Stamps
:SENSe:DATA? "TSTamp 1" or "TSTamp 2" or "TSTamp 3"
Returns the data in the timestamp measurement buffer for the specified Time Tag input.

:FORMat:DATA ASCii or INTeger
:FORMat:DATA?
:SENSe:DATA:POINts?
:SENSe:DATA:POINTs? "TSTamp 1" or "TSTamp 2" or "TSTamp 3"
:SENSe:DATA:TSTamp? "TSTamp 1" or "TSTamp 2" or "TSTamp 3", 

Processing Memory Overflow
:SENSe:DATA:MEMory:OVERflow:COUNt?
:SENSe:DATA:MEMory:OVERflow:COUNt? "TSTamp 1" or "TSTamp 2" or "TSTamp 3"
:SENSe:DATA:MEMory:SAVE FIRST or LAST
:SENSe:DATA:MEMory:SAVE?

Basic command

4-12

Operating and Programming Guide

Chapter 4 Command Quick Reference
Serial Interface Communication

Serial Interface Communication
The following commands are provided to allow you to configure the serial
interface port(s) for instrument communications.

Configuring I/O Port 1
R
R
R,F
R
R,F
R
R,F
R
R,F
R
R,F
R
R,F

:SYSTem:COMMunicate?
:SYSTem:COMMunicate:SERial1:BAUD 1200 or 2400 or 9600 or 19200
:SYSTem:COMMunicate:SERial1:BAUD?
:SYSTem:COMMunicate:SERial1:BITS 7 or 8
(59551A)
:SYSTem:COMMunicate:SERial1:BITS?
:SYSTem:COMMunicate:SERial1:FDUPlex ON or OFF
:SYSTem:COMMunicate:SERial1:FDUPlex?
:SYSTem:COMMunicate:SERial1:PACE XON or NONE
:SYSTem:COMMunicate:SERial1:PACE?
:SYSTem:COMMunicate:SERial1:PARity EVEN or ODD or NONE
:SYSTem:COMMunicate:SERial1:PARity?
:SYSTem:COMMunicate:SERial1:SBITs 1 or 2
(59551A)
:SYSTem:COMMunicate:SERial1:SBITs?

Configuring I/O Port 2 (59551A Only)
:SYSTem:COMMunicate?
:SYSTem:COMMunicate:SERial2:BAUD 1200 or 2400 or 9600 or 19200
R,F :SYSTem:COMMunicate:SERial2:BAUD?
R,F :SYSTem:COMMunicate:SERial2:BITS?
F :SYSTem:COMMunicate:SERial2:FDUPlex ON or OFF
R,F :SYSTem:COMMunicate:SERial2:FDUPlex?
F :SYSTem:COMMunicate:SERial2:PACE XON or NONE
R,F :SYSTem:COMMunicate:SERial2:PACE?
F :SYSTem:COMMunicate:SERial2:PARity EVEN or ODD or NONE or ONE
R,F :SYSTem:COMMunicate:SERial2:PARity?
R,F :SYSTem:COMMunicate:SERial2:SBITs?
F
F

Recovering the Last Query Response
:DIAGnostic:QUERy:RESPonse?

Basic command
R: Accessible via rear-panel PORT 1.
F: Accessible via Front-panel PORT 2 of the 59551A

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4-13

Chapter 4 Command Quick Reference
Receiver Initialization

Receiver Initialization
The following commands are provided to allow you to initialize or preset the
serial interface port(s) and the Receiver to their factory shipment values.

R

:SYSTem:COMMunicate:SERial1:PRESet
:SYSTem:COMMunicate:SERial2:PRESet (59551A Only)
:SYSTem:PRESet

Basic command
R: Accessible via Rear-panel PORT 1.

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Chapter 4 Command Quick Reference
Receiver Identification/Upgrade

Receiver Identification/Upgrade
The commands provided in this section allow you to query the identification of
the Receiver, and to perform firmware upgrades in the field after you obtain a
new firmware disk.

Reading Product Identification
*IDN?
Returns the Receiver identification.

Installing Firmware via I/O Port 1
R
R
R
R
R
R
R

*CLS
:DIAGnostic:DOWNload 
:DIAGnostic:ERASe
:DIAGnostic:ERASe?
:SYSTem:ERRor?
:SYSTem:LANGuage "INSTALL" or "PRIMARY"
:SYSTem:LANGuage?

Basic command
R: Accessible via Rear-panel Port 1.

Operating and Programming Guide

4-15

Chapter 4 Command Quick Reference
Receiver Identification/Upgrade

Receiver Commands at a Glance

4-16

Operating and Programming Guide

Chapter 4 Command Quick Reference
Receiver Identification/Upgrade

Receiver Commands at a Glance (cont’d)

Operating and Programming Guide

4-17

Chapter 4 Command Quick Reference
Status Reporting System at a Glance

Status Reporting System at a Glance

4-18

Operating and Programming Guide

5

Command Reference

Chapter 5 Command Reference
Chapter Contents

Chapter Contents
This chapter provides a description of each command that can be used
to operate the GPS Receiver. The commands are grouped by functions.
The functions are grouped and ordered the same as they are in
Chapter 4, “Command Quick Reference,” and on the foldout “Receiver
Commands at a Glance (cont’d).”
This chapter is organized as follows:
•

Command Syntax Conventions

page 5-4

•

Description Format

page 5-5

–

Commands and Returns

page 5-5

–

Query-Specific Information

page 5-6

•

•

•

5-2

GPS Satellite Acquisition

page 5-7

–

Facilitating Initial Tracking

page 5-9

–

Establishing Position

page 5-12

–

Selecting Satellites

page 5-17

–

Compensating for Antenna Delay

page 5-22

–

Monitoring Acquisition

page 5-24

1 PPS Reference Synchronization

page 5-27

–

Monitoring 1 PPS Synchronization

page 5-28

–

Assessing 1 PPS Quality

page 5-30

–

Operating in Holdover

page 5-36

Operating Status

page 5-39

–

Receiver Operation at a Glance

page 5-41

–

Reading the Error Queue

page 5-42

–

Reading the Diagnostic Log

page 5-43

–

Monitoring Status/Alarm Conditions

page 5-48

–

Assessing Receiver Health

page 5-70

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Chapter 5 Command Reference
Chapter Contents

•

System Time

page 5-73

–

Identifying Time of Next 1 PPS Reference Edge

page 5-74

–

Reading Current Time

page 5-75

–

Applying Local Time Zone Offset

page 5-77

–

Defining the 1 PPS Reference Edge (59551A Only) page 5-78

–

Reading Leap Second Status

page 5-79

•

Programmable Pulse Output (59551A Only)

page 5-83

•

Event Time Stamping (59551A Only)

page 5-89

–

Defining the Time-stamped Edge

page 5-90

–

Clearing Time Stamp Memory

page 5-91

–

Reading Time Stamps

page 5-92

–

Processing Memory Overflows

page 5-97

•

Serial Interface Communication

page 5-100

–

Configuring I/O Ports

page 5-101

–

Recovering the Last Query Response

page 5-108

•

Receiver Initialization

page 5-109

•

Receiver Identification/Upgrade

page 5-113

–

Reading Product Identification

page 5-114

–

Installing Firmware via I/O Port 1

page 5-115

See Appendix B, “Command Syntax and Style,” for details regarding
command Expanded Syntax, parameter types, and query response
types.

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Chapter 5 Command Reference
Command Syntax Conventions

Command Syntax Conventions
POSition

Means you MUST use either all the uppercase letters or
the entire word. The lowercase letters are optional. For
example, POS and POSITION are both valid. However,
POSI is not valid. (Note POSition is used here as an
example, but this convention is true for all command
keywords.) In other words, the short form of the
keywords is shown in uppercase.



The notation  ending a command keyword indicates
a numeric suffix, used to differentiate multiple
instances of the same structure. The numeric suffix is
applied to both the short and long forms. The valid
range for the value n is specified from an enumerated
list, for example [1|2|3], or from a range, for example
[1..3] to indicate any of the integers from 1 to 3.

"TSTamp 1"

When you see quotation marks in the command’s
parameter, you must send the quotation marks with the
command.

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Chapter 5 Command Reference
Description Format

Description Format
Commands and Returns

Product Compatibility
(if not present, the command is
supported by both products)

Command Index
Required characters are shown
in bold type. "..." denotes one
or more parameters; refer to
Expanded Syntax for details.

Default Setting
(commands only)

Scope
(commands only)

HP 59551A
c

Identifies a "basic"
(fundamental) command.

a b

:SYSTem:PRESet

:PULSe:STARt:DATE . . .

Synopsis

Identifies the date when the individual p
the pulse sequence) is generated at th
output.

Description

This command identifies the date when
the pulse sequence) is generated at the Pr

Command Mnemonic
Consult Appendix B: Command
Syntax and Style for notational style.

Expanded Syntax
:PULSe:STARt:DATE  range is 1994 to
The  range is 1 to 12.
The  range is 1 to 31.

Context Dependencies
If you select a date and time which occu
the completion of powerup and first GPS
successfuly find a start – and therefore w

When the command may
be issued

If the Receiver has been set up to use a t
and time, the parameters provided should
time.
:SYSTem:PRESet sets the date to January
Secondary effects on
other functions.
Concepts

Side Effects
Theory

Indicates that you cautiously use the :SYSTem:COMMunicate:SERIAL
commands to change the Receiver's serial interface parameters (i.e., BAUD, BITS,
PACE, PARity, and SBITs) from their factory default values. It is recommended that
you configure your PC's serial port settings to match the Receiver's factory default
values instead. However, if you must change the parameters, be sure to write down or
record all changes. Refer to Chapter 2, "Serial Interface Capabilities," in this guide for
more information.
This command can be executed
via the rear-panel PORT 1 only.

!

:SYSTem:COMMunicate:SERial:BAUD . . .

:SYSTem:PRESet

R

Not affected

Sets the baud rate of PORT 1.

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Chapter 5 Command Reference
Description Format

Query-Specific Information

Description of Response Formats (ASCII-encoded)
The following legend provides the meaning of each type of response
format. Refer to Table B-3 in Appendix B, “Command Syntax and
Style,” for details.
Example

Description

0

Single character,
one or zero

± dd

+10

Integer

± d.d

+1.5

Fixed-point number

+1.00000E-009

Floating-point number

LOCK

Alphanumeric characters

“ XYZ ”

“19:49:51” or “No error”

Quoted string

± dd, ...

+14, +15, +18, +22, +29

Comma-separated list of
integers

“Log 001:19950101.00:00:00: Power on”,
“Log 002:19950101.00:10:00: Log cleared”

Comma-separated list of
quoted strings

RESPONSE FORMAT
0 or 1

± d.dEe
XYZ

“ XYZ”, ...

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Chapter 5 Command Reference
GPS Satellite Acquisition

GPS Satellite Acquisition
The GPS Receiver is designed to acquire time transfer information (time, date,
and position) from the GPS satellites, which is used by the Receiver’s internal
reference oscillator and SmartClock technology to lock to GPS. It acquires a
precise time and date by tracking at least one satellite. By tracking at least four
satellites, it precisely determines the position of the antenna. With this
information, the Receiver can produce a precise 1 PPS signal that is exactly
synchronous to Coordinated Universal Time (UTC) as determined by GPS.
The following commands are provided to facilitate initiate GPS satellite
tracking, to establish accurate GPS antenna position, to select or ignore
satellites, to compensate for antenna cable delay, and to monitor the
acquisition.
! Facilitating Initial Tracking
:GPS:INITial:DATE ...
:GPS:INITial:POSition ...
:GPS:INITial:TIME ...

! Establishing Position
:GPS:POSition ...
:GPS:POSition?
:GPS:POSition:ACTual?
:GPS:POSition:HOLD:LAST?
:GPS:POSition:HOLD:STATe?
:GPS:POSition:SURVey:PROGress?
:GPS:POSition:SURVey:STATe ...
:GPS:POSition:SURVey:STATe?
:GPS:POSition:SURVey:STATe:POWerup ...
:GPS:POSition:SURVey:STATe:POWerup?

! Selecting Satellites
:GPS:SATellite:TRACking:EMANgle ...
:GPS:SATellite:TRACking:EMANgle?
:GPS:SATellite:TRACking:IGNore ...
:GPS:SATellite:TRACking:IGNore?
:GPS:SATellite:TRACking:INCLude ...
:GPS:SATellite:TRACking:INCLude?
:GPS:SATellite:TRACking::ALL
:GPS:SATellite:TRACking::COUNt?
:GPS:SATellite:TRACking::STATe?

Operating and Programming Guide

(59551A)
(59551A)
(59551A)
(59551A)
(59551A)
...

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GPS Satellite Acquisition

! Compensating for Antenna Delay
:GPS:REFerence:ADELay ...
:GPS:REFerence:ADELay?

! Monitoring Acquisition
:GPS:REFerence:VALid?
:GPS:SATellite:TRACking?
:GPS:SATellite:VISible:PREDicted?
:GPS:SATellite:TRACking:COUNt?
:GPS:SATellite:VISible:PREDicted:COUNt?

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GPS Satellite Acquisition

Facilitating Initial Tracking ______________________________

:GPS:INITial:DATE . . .
Sets an approximate date for faster initial GPS acquisition.

:SYSTem:PRESet
Not affected

VOLATILE

This command sets an approximate date for faster initial GPS acquisition.
Following powerup, the Receiver obtains the current date from satellite data.
This process occurs automatically. Providing an approximate date, however,
reduces the time to initial GPS tracking by assisting the Receiver in finding
satellites.
Expanded Syntax
:GPS:INITial:DATE ,,
Parameter

Range: the year, month, and day must be valid.
Context Dependencies

This command is valid prior to first satellite tracked (see bit 0 of the Operation
Status Register). Sending this command after this time will generate
error -221.
The initial date and time needs to be within 3 minutes of the actual date and
time to be effective in enabling faster initial GPS acquisition.

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GPS Satellite Acquisition

Facilitating Initial Tracking ____________________ (continued)

:GPS:INITial:POSition . . .

:SYSTem:PRESet

Sets an approximate position for faster initial GPS acquisition.

:Not affected

VOLATILE

This command sets an approximate position for faster initial GPS acquisition.
Following powerup, the Receiver refines its position from the satellite data.
This process occurs automatically. This command is most effective when the
retained position differs significantly from the Receiver’s true position.
Expanded Syntax
:GPS:INITial:POSition N or S, ,
,
,
E or W, ,
,
,

or

Parameter

This command requires three position coordinates: latitude, longitude, and
height. Position must be specified with respect to the World Geodetic System
1984 (WGS-1984) datum absolute earth coordinates.
The latitude coordinate is preceded by either N or S, which denotes the
northern or southern hemisphere, respectively. The longitude coordinate is
preceded by either E or W, which denotes the eastern or western hemisphere,
respectively.
The following table lists the allowed settings of other parameters:
Parameter

Range

Precision

Parameter

Range

Precision



0 to 90

1



0 to 180

1



0 to 59

1



0 to 59

1



0 to 59.999

0.001



0 to 59.999

0.001



-1000.00 to
18,000.00

0.01

Context Dependencies

This command is valid while the Receiver is in survey mode prior to first
computed position. Sending this command while the Receiver is not in survey
mode will generate error -221.

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Chapter 5 Command Reference
GPS Satellite Acquisition

Facilitating Initial Tracking ____________________ (continued)

:GPS:INITial:TIME . . .

:SYSTem:PRESet

Sets an approximate time for faster initial GPS acquisition.

Not affected

VOLATILE

This command sets an approximate time for faster initial GPS acquisition.
Following powerup, the Receiver obtains the current time from satellite data.
This process occurs automatically. Providing an approximate time, however,
reduces the time to initial GPS tracking by assisting the Receiver in finding
satellites.
Expanded Syntax
:GPS:INITial:TIME ,,
Parameter

Range: all parameters (hour, minutes, seconds) must be valid.
Context Dependencies

This command is valid prior to first satellite tracked (see bit 0 of the Operation
Status Register). Sending this command after this time will generate
error -221.
The initial date and time needs to be within 3 minutes of the actual date and
time to be effective in enabling faster initial GPS acquisition.

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GPS Satellite Acquisition

Establishing Position_____________________________________

:GPS:POSition . . .

:SYSTem:PRESet

Defines the position of the Receiver.

latitude:
longitude:
height:

N 0:00:00.000
E 0:00:00.000
0 meters

NON-VOLATILE

This command defines the position of the Receiver. The Receiver uses this
position to predict satellite visibility and to determine time. An accurate
position is necessary for precise time transfer.
Expanded Syntax
:GPS:POSition

N or S, ,
,
,
E or W, ,
,
,

or


:GPS:POSition LAST
:GPS:POSition SURVey
Parameter

The numeric form of this command requires three position coordinates:
latitude, longitude, and height. Position must be specified with respect to the
World Geodetic System 1984 (WGS-1984) datum absolute earth coordinates.
The latitude coordinate is preceded by either N or S, which denotes the
northern or southern hemisphere, respectively. The longitude coordinate is
preceded by either E or W, which denotes the eastern or western hemisphere,
respectively.
The following table lists the allowed settings of other parameters:
Parameter

Range

Precision

Parameter

Range

Precision



0 to 90

1



0 to 180

1



0 to 59

1



0 to 59

1



0 to 59.999

0.001



0 to 59.999

0.001



-1000.00 to
18,000.00

0.01

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Chapter 5 Command Reference
GPS Satellite Acquisition

Establishing Position ___________________________ (continued)
LAST denotes the last specified position. This parameter is provided to cancel
surveying (automatic position computation) and restore the last position
setting.
SURVey directs the Receiver to stop surveying and use the computed position.
This position is the average of individual position computations.
Context Dependencies

Error -221 is generated if this command is sent as SURV and no valid survey
calculation has ever been computed.
Side Effects

This command stops position surveying. The computed position is retained and
applied only when SURVey is specified.

:GPS:POSition?

RESPONSE FORMAT

Returns the current average position of the GPS antenna.

XYZ or
± dd or
± d.dEe,
...

This query returns the current average position of the Receiver.
Response

Returns a list of values defining the Receiver position:
N or S, , , ,
E or W, ,, ,
 or .

Context Dependencies

Error -230 is generated if in survey and first calculation has not occurred.

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GPS Satellite Acquisition

Establishing Position___________________________ (continued)

:GPS:POSition:ACTual?

RESPONSE FORMAT

Returns the current instantaneous position of the GPS antenna.

XYZ or
± dd or
± d.dEe,
...

This query returns the current instantaneous position of the GPS antenna.
Response

Returns a list of values defining the Receiver position:
N or S, , , ,
E or W, ,, ,
 or .
Context Dependencies

Error -230 is generated if in survey and first calculation has not occurred.

:GPS:POSition:HOLD:LAST?

RESPONSE FORMAT

Returns the last position-hold setting.

XYZ or
± dd or
± d.dEe,
...

This query returns the last position-hold setting, which is restored when the
:GPS:POSition LAST command is sent. Refer to the description of the
:GPS:POSition command on page 5-13 for details.
Response

Returns a list of values defining the Receiver position:
N or S, , , ,
E or W, ,, ,
 or .
Context Dependencies

This query is always valid, but if the Receiver has not been in position-hold
mode since it was preset (see :SYSTem:PRESet), the value returned will be the
preset position.

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GPS Satellite Acquisition

Establishing Position ___________________________ (continued)

:GPS:POSition:HOLD:STATe?
Identifies whether the Receiver is in position-hold or survey mode.

RESPONSE FORMAT

0 or 1

This query identifies whether the Receiver is in position-hold or survey mode.
In survey mode, the Receiver continually refines its position. In position-hold
mode, the position setting does not change.
Response

A value of 0 indicates not in position hold (in survey mode); a value of 1
indicates in position hold.

:GPS:POSition:SURVey:PROGress?
Returns percent completed while in survey mode.

RESPONSE FORMAT

± d.d

This query returns percent completed while in survey mode. Automatic
transition to position-hold mode occurs following completion of survey mode
(indicated by 100).
Response

The range is 0 to 100%. The units are percent.
Context Dependencies

This query is only valid while surveying for position (:GPS:POS:SURV:STATe?
returns ONCE or status bit 3 = 0 in the Operation Status Register). If queried
while not surveying, error -221 is generated.

:GPS:POSition:SURVey:STATe . . .
Initiates survey mode during which the Receiver determines its
position from satellite data.

:SYSTem:PRESet

ONCE

This command initiates survey mode during which the Receiver determines its
position from satellite data. The Receiver refines successive positional
estimates to obtain a final position, transitions from survey to position-hold
mode.
Expanded Syntax
:GPS:POSition:SURVey:STATe ONCE

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GPS Satellite Acquisition

Establishing Position___________________________ (continued)

:GPS:POSition:SURVey:STATe?

RESPONSE FORMAT

Identifies whether the Receiver is in survey or position-hold mode.

XYZ or 0

This query identifies whether the Receiver is in survey or position-hold mode.
In survey mode, the Receiver continually refines its position. In position-hold
mode, the position does not change.
Response

A response of ONCE indicates that the Receiver is in survey mode. A response
of 0 indicates the Receiver is in position-hold mode.

:GPS:POSition:SURVey:STATe:POWerup . . .

:SYSTem:PRESet

Selects position mode to be used at powerup.

ON
NON-VOLATILE

This command specifies whether the Receiver always surveys at powerup or
restores its last position at powerup.
Expanded Syntax
:GPS:POSition:SURVey:STATe:POWerup ON or OFF
Parameter

OFF sets the Receiver to powerup in the last valid position. ON sets the
Receiver to survey on powerup.

:GPS:POSition:SURVey:STATe:POWerup?

RESPONSE FORMAT

Returns the position mode to be used at powerup.

0 or 1

This query returns the position mode to be used at powerup.
Response

A value of 0 indicates the Receiver is set to powerup in the last valid position.
A value of 1 indicates the Receiver is set to survey on powerup.

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GPS Satellite Acquisition

Selecting Satellites _______________________________________

:GPS:SATellite:TRACking:EMANgle . . .
Sets the GPS elevation mask angle value (in degrees).

:SYSTem:PRESet

10
NON-VOLATILE

This command instructs the Receiver to allow tracking those satellites for
which the elevation angle is greater than this elevation mask angle. Satellites
below this elevation are visible, but will not be tracked.
Expanded Syntax
:GPS:SATellite:TRACking:EMANgle 
Parameter

 range is 0 degrees (horizon) to 89 degrees. The resolution is
1 degree.
The maximum recommended value while the position is being surveyed is
15 degrees, to allow tracking of four satellites needed for an accurate position
determination.
Once the survey is complete, the elevation mask angle can be increased to avoid
interference problems caused by buildings and trees and minimize effects of
multipath, if necessary.
Values above 40 degrees severely limit GPS signal availability, and are not
recommended.

:GPS:SATellite:TRACking:EMANgle?
Returns the GPS elevation mask angle value.

RESPONSE FORMAT

± dd

This query returns the GPS elevation mask angle value.
Response

The range is 0 degrees to 89 degrees.

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GPS Satellite Acquisition

Selecting Satellites _____________________________(continued)
59551A

:GPS:SATellite:TRACking:IGNore . . .

:SYSTem:PRESet

Adds the specified satellites to the list that the Receiver ignores
for tracking.

No satellites ignored

NON-VOLATILE

This command adds the specified satellites to the list that the Receiver ignores
for tracking. Each satellite is identified by its pseudorandom noise code (PRN).
Expanded Syntax
:GPS:SATellite:TRACking:IGNore , . . ., 
:GPS:SATellite:TRACking:IGNore:NONE
:GPS:SATellite:TRACking:IGNore:ALL
Parameter

 parameter is the pseudorandom noise code of the satellite(s) you want
the Receiver to ignore. Each satellite has its own unique PRN.
Context Dependencies

This command is always valid. On send, if any item in the  list is
invalid, the entire list will be rejected. Error -222 will be generated.

59551A

:GPS:SATellite:TRACking:IGNore?
Returns list of satellites to ignore.

RESPONSE FORMAT

± dd, ...

This query returns a list of satellites to ignore for tracking. Each satellite is
identified by its pseudorandom noise code (PRN). Zero (0) indicates no
satellites being ignored.
Response

A value of 0 indicates no satellites being ignored. If any satellite is being
ignored, the pseudorandom noise code (PRN) of the satellite is returned.
Context Dependencies

This query is always valid.

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Chapter 5 Command Reference
GPS Satellite Acquisition

Selecting Satellites _____________________________(continued)
59551A

:GPS:SATellite:TRACking:INCLude . . .
Adds the specified satellites to the list that the Receiver considers
for tracking.

:SYSTem:PRESet
All satellites included

NON-VOLATILE

This command adds the specified satellites to the list that the Receiver
considers for tracking. Actual satellite selection is based on satellite visibility,
geometry, and health.
Expanded Syntax
:GPS:SATellite:TRACking:INCLude , . . ., 
:GPS:SATellite:TRACking:INCLude:NONE
:GPS:SATellite:TRACking:INCLude:ALL
Parameter

 parameter is the pseudorandom noise code of the satellite(s) you want
the Receiver to include. Each satellite has its own unique PRN.
Context Dependencies

This command is always valid. On send, if any item in the  list is
invalid, the entire list will be rejected. Error -222 will be generated.

59551A

:GPS:SATellite:TRACking:INCLude?
Returns a list of satellites to include.

RESPONSE FORMAT

± dd, ...

This query returns a list of satellites to include for tracking. Each satellite is
identified by its pseudorandom noise code (PRN). Zero (0) indicates no
satellites being included (i.e., the satellites are still on the ignored list).
Context Dependencies

This query is always valid.

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Chapter 5 Command Reference
GPS Satellite Acquisition

Selecting Satellites______________________________ (continued)

:GPS:SATellite:TRACking:IGNore:COUNt?
Returns the number of satellites that are on the list to ignore for
tracking.

RESPONSE FORMAT

± dd

:GPS:SATellite:TRACking:INClude:COUNt?
Returns the number of satellites that are on the list to include for
tracking.

± dd

The query :GPS:SATellite:TRACking:IGNore:COUNt? returns the number of
satellites that are on the list to ignore for tracking.
The query :GPS:SATellite:TRACking:INClude:COUNt? returns the number of
satellites that are on the list to be included for tracking.
Response

There may be some delay between changes made to the list of satellites being
ignored and their actual removal and inclusion in the tracking process.
At :SYSTem:PRESet, all satellites are put on the list to include for tracking.

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GPS Satellite Acquisition

Selecting Satellites______________________________ (continued)

:GPS:SATellite:TRACking:IGNore:STATe? . . .
Returns the ignored status of individual satellites.

RESPONSE FORMAT

0 or 1

:GPS:SATellite:TRACking:INClude:STATe? . . .
Returns the include status of the specified satellite.

0 or 1

The query :GPS:SATellite:TRACking:IGNore:STATe? returns the ignored
status of the specified satellite. A satellite is specified by its pseudorandom
noise code (PRN).
The query :GPS:SATellite:TRACking:INClude:STATe? returns the include
status of the specified satellite. A satellite is specified by its pseudorandom
noise code (PRN).
There may be some delay between changes made to the list of satellites being
ignored and their actual removal and inclusion in the tracking process.
Expanded Syntax
:GPS:SATellite:TRACking:IGNore:STATe? 
:GPS:SATellite:TRACking:INClude:STATe? 
Parameter

 parameter is the pseudorandom noise code of the satellite(s) you want
the Receiver to ignore or include. Each satellite has its own unique PRN.
Response

A value of 0 indicates not on the selected list.
A value of 1 indicates on the selected list.
Context Dependencies

After a :SYSTem:PRESet, all satellites are removed from the list to ignore.

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GPS Satellite Acquisition

Compensating for Antenna Delay_________________________

:GPS:REFerence:ADELay . . .

:SYSTem:PRESet

Sets the GPS antenna delay value in seconds.

0.0
NON-VOLATILE

This command sets the GPS antenna delay value in seconds. It instructs the
Receiver to output its 1 PPS output pulse earlier in time to compensate for
antenna cable delay.
CAUTION

Using this command while the Receiver is in normal locked operation could
cause the Receiver go into holdover.
Expanded Syntax
:GPS:REFerence:ADELay 
Parameter

Numeric_value range is 0 to 0 .000999999 seconds. The resolution is
1 nanosecond.
Zero cable delay is set for a zero-length antenna cable. Consult a cable data
book for the delay per meter for the particular antenna cable used in order to
compute the total cable delay needed for a particular installation.
See Also
:GPS:REFerence:ADELay?

The tables below list the delay values that you need to use with the
:GPS:REFERENCE:ADELAY  command for the available cable
assemblies.

Delay Values for the 58518A/519A and 58518AA/519AA RG-213 Antenna
Cables
Cable Option

Length

RG 213 or Belden 8267
Antenna Delay
Value

001

1m

5.0 nanoseconds

002

2m

10.3 nanoseconds

005

5m

25.2 nanoseconds

010

10 m

50.5 nanoseconds

015

15 m

75.7 nanoseconds

030

30 m

151.5 nanoseconds

050

50 m

252.5 nanoseconds

The nominal delay value is labeled on the cables. Refer to the Designing Your
GPS Antenna System Configuration Guide for more information.

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GPS Satellite Acquisition

Compensating for Antenna Delay_____________(continued)

Delay Values for the 58520A/521A and 58520AA/521A LMR 400
Antenna Cables
Cable Option

Length

LMR 400 Antenna Delay Value

001

1m

3.9 nanoseconds

002

2m

8.0 nanoseconds

005

5m

19.6 nanoseconds

010

10 m

39.3 nanoseconds

015

15 m

59.0 nanoseconds

030

30 m

118.0 nanoseconds

060

60 m

236.1 nanoseconds

110

110 m

432.9 nanoseconds

The nominal delay value is labeled on the cables. Refer to the Designing Your
GPS Antenna System Configuration Guide for more information.

:GPS:REFerence:ADELay?
Returns the GPS antenna delay value in seconds.

RESPONSE FORMAT

± d.dEe

This query returns the GPS antenna delay value in seconds. This is the delay
value set by the system installer (or the factory default). It is not a value
measured by the Receiver.
Response

The time units are seconds.

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Chapter 5 Command Reference
GPS Satellite Acquisition

Monitoring Acquisition ___________________________________

:GPS:REFerence:VALid?

RESPONSE FORMAT

Identifies whether the 1 PPS signal is valid.

0 or 1

This query identifies that the 1 PPS signal has locked to a valid GPS reference
and the 1 PPS signal itself is valid.
Response

A value of 1 indicates signal is valid.
A value of 0 indicates signal is not valid.

:GPS:SATellite:TRACking?

RESPONSE FORMAT

± dd, ...

Returns a list of all satellites being tracked.

This query returns a list of all satellites being tracked. Each satellite is
identified by its pseudorandom noise code (PRN).
Response

A comma-separated list of satellite pseudorandom noise codes ().
The range of each  is 1 to 32.
A response of 0 indicates no satellites being tracked.

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Chapter 5 Command Reference
GPS Satellite Acquisition

Monitoring Acquisition _________________________ (continued)

:GPS:SATellite:VISible:PREDicted?

RESPONSE FORMAT

± dd, ...

Returns the list of satellites (PRN) that the almanac predicts
should be visible, given date, time, and location.

This query returns the list of satellites (PRN) that the almanac predicts should
be visible, given date, time, and location (if any of these values are incorrect,
the prediction will be incorrect). Each satellite is identified by its
pseudorandom noise code (PRN).
Response

A comma-separated list of satellite pseudorandom noise codes ().
The range of each  is 1 to 32.
A response of 0 indicates no satellites predicted visible.
Theory

Satellites must be in view to be tracked. At least four satellites must be in view,
and tracked, to determine the position in position survey operation. Only one
satellite must be in view, and tracked, to maintain operation of the reference
oscillator locked to GPS when in position hold operation.

:GPS:SATellite:TRACking:COUNt?

RESPONSE FORMAT

Returns the number of satellites being tracked.

± dd

This query returns the number of satellites being tracked.
Response

If there are no satellites being tracked, this query returns a 0.

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Chapter 5 Command Reference
GPS Satellite Acquisition

Monitoring Acquisition _________________________ (continued)

:GPS:SATellite:VISible:PREDicted:COUNt?
Returns the number of satellites that the almanac predicts should
be visible, given date, time, and location.

RESPONSE FORMAT

± dd

This query returns the number of satellites that the almanac predicts should
be visible, given date, time, and location (if any of these are incorrect, the
prediction will be incorrect).
Response

Number of satellites predicted visible.
Theory

Satellites must be in view to be tracked. At least four satellites must be in view,
and tracked, to determine the position in position survey operation. Only one
satellite must be in view, and tracked, to maintain operation of the reference
oscillator locked to GPS when in position hold operation.

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Chapter 5 Command Reference
1 PPS Reference Synchronization

1 PPS Reference Synchronization
1 PPS and 10 MHz (58503B only) output signals are generated by the
Receiver’s internal reference oscillator. This oscillator is synchronized
(phased locked) to GPS while a sufficient number of satellites are tracked.
When the GPS signal is interrupted or absent, the Receiver maintains timing
and frequency accuracy through its oscillator “holdover” process. While in
holdover, the frequency of the reference oscillator is adjusted as necessary to
compensate for aging characteristics. The Receiver returns to “locked”
operation through a “holdover recovery” process.
The following commands are provided to monitor the operating mode of the
reference oscillator, to determine the accuracy and stability of the reference
output signal(s), and to control the oscillator holdover process.
! Monitoring 1 PPS Synchronization
:SYNChronization:STATe?
:DIAGnostic:ROSCillator:EFControl:RELative?
:LED:GPSLock?
:LED:HOLDover?

! Assessing 1 PPS Quality
:SYNChronization:FFOMerit?
:SYNChronization:HOLDover:TUNCertainty:PREDicted?
:SYNChronization:HOLDover:TUNCertainty:PRESent?
:SYNChronization:TFOMerit?
:SYNChronization:TINTerval?
:SYNChronization:HOLDover:DURation?
:SYNChronization:HOLDover:DURation:THReshold ...
:SYNChronization:HOLDover:DURation:THReshold?
:SYNChronization:HOLDover:DURation:THReshold:EXCeeded?

! Operating in Holdover
" Initiating Manual Holdover
:SYNChronization:HOLDover:INITiate

" Recovering from Holdover
:SYNChronization:HOLDover:WAITing?
:SYNChronization:HOLDover:RECovery:INITiate
:SYNChronization:HOLDover:RECovery:LIMit:IGNore
:SYNChronization:IMMediate

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1 PPS Reference Synchronization

Monitoring 1 PPS Synchronization _______________________

:SYNChronization:STATe?

RESPONSE FORMAT

Returns the Receiver state.

XYZ

This query returns the Receiver state.
Response

OFF, or HOLD, or WAIT, or REC, or LOCK, or POW.
OFF indicates in diagnostic mode or a temporary start-up mode; HOLD
indicates in manual holdover; WAIT indicates waiting for external conditions
to allow recovery from holdover; REC indicates actively recovering from
holdover; LOCK indicates locked to GPS; POW indicates in powerup prior to
first lock.
Context Dependencies

:SYSTem:PRESet sets the state to POWerup.

:DIAGnostic:ROSCillator:EFControl:RELative?
Returns the Electronic Frequency Control (EFC) output value of
the internal reference oscillator.

RESPONSE FORMAT

± d.dEe

This query returns the Electronic Frequency Control (EFC) output value of the
internal reference oscillator. It returns a percentage value.
Response

Range is -100% to +100%.

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Chapter 5 Command Reference
1 PPS Reference Synchronization

Monitoring 1 PPS Synchronization _____________ (continued)

:LED:GPSLock?
Returns the state of the front-panel GPS Lock LED.

RESPONSE FORMAT

0 or 1

This query returns the state of the front-panel GPS Lock LED. The Receiver
sets this indicator during normal operation when it has locked the internal
reference oscillator and 1 PPS output to GPS.
Response

A value of 0 indicates the LED is off.
A value of 1 indicates the LED is on.

:LED:HOLDover?
Returns the state of the front–panel Holdover LED.

RESPONSE FORMAT

0 or 1

This query returns the state of the front-panel Holdover LED. The Receiver
sets this indicator when in holdover operation.
Response

A value of 0 indicates the LED is off.
A value of 1 indicates the LED is on.

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1 PPS Reference Synchronization

Assessing 1 PPS Quality__________________________________

:SYNChronization:FFOMerit?
Returns the Frequency Figure of Merit.

RESPONSE FORMAT

± dd

This query returns the Frequency Figure of Merit (FFOM). Use this query
when you want to know the stability of the Receiver’s 10 MHz output.
The 10 MHz output is controlled by the SmartClock’s Phase-Locked Loop
(PLL). Thus, the FFOM value is determined by monitoring the status of
the PLL.
Response

The following table lists and defines the FFOM values (0 thru 3) that could be
returned.
FFOM Value

Definition

0

PLL stabilized—10 MHz output within specification.

1

PLL stabilizing

2

PLL unlocked (holdover)—Initially the 10 MHz output will be
within specifications. However, when in holdover, the 10 MHz
output will eventually drift out of specification.

3

PLL unlocked (not in holdover)—Do not use the output.

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Chapter 5 Command Reference
1 PPS Reference Synchronization

Assessing 1 PPS Quality ________________________ (continued)

:SYNChronization:HOLDover:TUNCertainty:PREDicted?
Returns an estimate of the time interval error that can be expected
for a one day holdover, given the current state of SmartClock
learning in the Receiver.

RESPONSE FORMAT

± d.dEe, 0 or 1

This query returns an estimate of the time interval error that can be expected
for a one day holdover, given the current state of SmartClock learning in the
Receiver.
Response

The first number in the response is the estimated time interval error. The units
are seconds, the resolution is 100 nanoseconds.
The second number in the response identifies the holdover state. A value of 0
indicates the Receiver is not in holdover; a value of 1 indicates the Receiver is
in holdover.
Context Dependencies

This query is not valid prior to first lock following powerup (see bit 2 of the
Powerup Status Register) or :SYSTem:PRESet. Sending this query before first
lock will generate error -230.

:SYNChronization:HOLDover:TUNCertainty:PRESent?
Returns the current time interval error during holdover operation,
given the current state of SmartClock learning in the Receiver.

RESPONSE FORMAT

± d.dEe

This query returns the current time error during holdover operation, given the
current state of SmartClock learning in the Receiver.
Response

The time error units are seconds.
Context Dependencies

This query is valid when the Receiver is in holdover. If not in holdover,
error -230 is generated.

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1 PPS Reference Synchronization

Assessing 1 PPS Quality ________________________ (continued)

:SYNChronization:TFOMerit?

RESPONSE FORMAT

± dd

Returns the Time Figure of Merit.

This query returns the Time Figure of Merit. Use this query when you want to
know the accuracy of the Receiver’s 1 PPS output. A low TFOM value indicates
a more accurate output. A value of 3 indicates that the Time Error ranges from
100 to 1000 nanoseconds.
Response

The following table lists the TFOM values that could be returned and provides
the corresponding Time Error.
TFOM Value

Time Error
(in nanoseconds)

TFOM Value

Time Error
(in nanoseconds)

0*

less than 1

5

104–105

1*

1–10

6

105–106

2*

10–100

7

106–107

3

100–1000

8

107–108

4

103–104

9

greater than 108

* The TFOM values 0, 1, and 2 are not presently used in the 58503B and 59551A products. The
58503B and 59551A products will display TFOM values ranging from 9 to 3, which is consistent with
the specified accuracies of each product

:SYNChronization:TINTerval?

RESPONSE FORMAT

Returns the difference or timing shift between the SmartClock 1
PPS and the GPS 1 PPS signals.

± d.dEe

This query returns the difference or timing shift between the SmartClock
1 PPS and the GPS 1 PPS signals. It generates an error when this interval is
unavailable (That is, if no GPS 1 PPS).
Response

Time interval units are seconds.
Resolution is 1E-10 seconds.

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1 PPS Reference Synchronization

Assessing 1 PPS Quality ________________________ (continued)

:SYNChronization:HOLDover:DURation?
Returns the duration of the present or most recent period of
operation in the holdover and holdover processes.

RESPONSE FORMAT

± d.dEe, 0 or 1

This query returns the duration of the present or most recent period of
operation in the holdover and holdover processes. This is the length of time the
reference oscillator was not locked to GPS. The time units are seconds.
Response

The first number in the response is the holdover duration. The duration units
are seconds, and the resolution is 1 second.
If the Receiver is in holdover, the response quantifies the current holdover
duration. If the Receiver is not in holdover, the response quantifies the
previous holdover.
The second number in the response identifies the holdover state. A value of 0
indicates the Receiver is not in holdover; a value of 1 indicates the Receiver is
in holdover.
Context Dependencies

This query is always valid. If this query is sent before the first holdover has
occurred, the response will be 0,0, indicating that the Receiver is currently not
in holdover and last holdover duration was 0 seconds (user infers there has not
been one yet).
Set to 0,0 after a :SYSTem:PRESet. If there was a prior holdover, the duration
will be lost.

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1 PPS Reference Synchronization

Assessing 1 PPS Quality ________________________ (continued)

:SYNChronization:HOLDover:DURation:THReshold . . .
Sets the duration (in seconds) to be used as a limit each time
holdover begins.

:SYSTem:PRESet

86400
(i.e., 1 day)
NON-VOLATILE

This command sets the duration (in seconds) which represents a limit against
which the elapsed time of holdover is compared. If the elapsed time in holdover
(and associated processes) exceeds the limit, a flag is set. The flag indicating
the limit is exceeded can be queried using the
:SYNC:HOLD:DUR:THR:EXCeeded? query.
Expanded Syntax
:SYNChronization:HOLDover:DURation:THReshold 
Parameter

Resolution of the  parameter is 1 second.

:SYNChronization:HOLDover:DURation:THReshold?
Returns the duration (in seconds) which represents a limit against
which the elapsed time of holdover is compared.

RESPONSE FORMAT

± dd

This query returns the duration (in seconds) which represents a limit against
which the elapsed time of holdover is compared. If the elapsed time of holdover
(and associated processes) exceeds the limit, a flag is set.
Expanded Syntax
:SYNChronization:HOLDover:DURation:THReshold?
Response

The threshold units are seconds.
The resolution is 1 second

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1 PPS Reference Synchronization

Assessing 1 PPS Quality ________________________ (continued)

:SYNChronization:HOLDover:DURation:THReshold
:EXCeeded?
Identifies if the Receiver has been in holdover longer than the
amount of time specified by the THReshold command.

RESPONSE FORMAT

0 or 1

This query identifies if the Receiver has been in holdover longer than the
amount of time specified by the THReshold command. If it has, 1 will be
returned.
Response

A value of 1 indicates that the Receiver is in holdover, and has been operating
in holdover for a duration that exceeds the specified duration.
The value 0 indicates either the Receiver is not in holdover, or it has been in
holdover for less than the specified duration.

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1 PPS Reference Synchronization

Operating in Holdover ____________________________________
" Initiating Manual Holdover __________________________________

:SYNChronization:HOLDover:INITiate
Places the Receiver in holdover mode.

EVENT

This command places the Receiver in holdover mode. The Receiver will stay in
holdover until you send :SYNC:HOLD:REC:INIT.
Context Dependencies

This command is not valid prior to the first lock following powerup (see bit 2 of
the Powerup Status Register) or :SYSTem:PRESet. Sending this command
before the first lock will generate error -221.
See Also
:SYNChronization:HOLDover:RECovery:INITiate

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1 PPS Reference Synchronization

Operating in Holdover __________________________ (continued)
" Recovering from Holdover _________________________________

:SYNChronization:HOLDover:WAITing?
Returns prioritized reason for why the Receiver is waiting to
recover.

RESPONSE FORMAT

XYZ

This query returns prioritized reason for why the Receiver is waiting to
recover.
Response

HARD indicates there is an internal hardware reason, GPS indicates there are
no satellites, LIM indicates the time interval between GPS and internal
oscillator is exceeding the limit, and NONE indicates the Receiver isn’t waiting
to recover.
Note that if holdover has been initiated by sending the :SYNC:HOLD:INIT
command, the Receiver is not waiting to recover; the response is NONE.
This query is always valid. If not in holdover and waiting to recover, NONE will
be the response.

:SYNChronization:HOLDover:RECovery:INITiate
Initiates a recovery from manually initiated holdover.

EVENT

This command initiates a recovery from manually initiated holdover. Use this
command to take the Receiver out of a manually selected holdover. This
command is not needed to initiate holdover recovery in any other situation.
See Also
:SYNChronization:HOLDover:INITiate

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1 PPS Reference Synchronization

Operating in Holdover __________________________ (continued)
" Recovering from Holdover (continued)

:SYNChronization:HOLDover:RECovery:LIMit:IGNore
Initiates recovery from holdover if recovery was inhibited by time
intervals exceeding limit.

EVENT

This command initiates recovery from holdover if recovery was inhibited by
time intervals exceeding limit.
The time interval used for this comparison is the time interval between the
internal oscillator’s 1 PPS edge and the GPS system’s 1 PPS edge. When this
time interval consistently exceeds the specified limit, the instrument enters
the holdover state, “Waiting to Recover.”
Recovery is initiated when the time intervals consistently fall within limits,
or when the limit is ignored by issuing this command.

:SYNChronization:IMMediate
Initiates a near-instantaneous alignment of the GPS 1 PPS and
Receiver output 1 PPS if the command is issued during recovery
from holdover.

EVENT

This command initiates a near-instantaneous alignment of the GPS 1 PPS and
Receiver output 1 PPS if the command is issued during recovery from holdover.
Context Dependencies

This command is only valid when recovering from holdover. See bit 2 of the
Holdover Status Register (if it is 1, this command is okay). Sending this
command when the Receiver is not recovering will generate error -221.

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Operating Status

Operating Status
This section describes the commands that can be use to obtain Receiver status
information. There are several ways to obtain Receiver status using
commands. For example, you can send a command to display the Receiver
Status screen, to read the error queue, and to read the diagnostic log. You can
also send a sequence of commands to read and control the status registers for
alarm generation.
This section defines all of the commands used for status reporting.
A comprehensive discussion on how you can monitor and control alarm
conditions using the status registers is included.
! Receiver Operation at a Glance
:SYSTem:STATus?
:SYSTem:STATus:LENGth?

! Reading the Error Queue
:SYSTem:ERRor?

! Reading the Diagnostic Log
:DIAGnostic:LOG:CLEar
:DIAGnostic:LOG:READ:ALL?
:DIAGnostic:LOG:CLEar ...
:DIAGnostic:LOG:COUNt?
:DIAGnostic:LOG:READ?
:DIAGnostic:LOG:READ? ...

! Monitoring Status/Alarm Conditions
" Clearing and Presetting Alarms
*CLS
:STATus:PRESet:ALARm

" Reading and Qualifying Alarms
:LED:ALARm?
*SRE ...
*SRE?
*STB?

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Operating Status

" Reading and Qualifying Receiver Status
 = OPERation
 = OPERation:HARDware
 = OPERation:HOLDover
 = OPERation:POWerup

 = QUEStionable

:STATus::CONDition?
:STATus::EVENt?
:STATus::ENABle ...
:STATus::ENABle?
:STATus::NTRansition ...
:STATus::NTRansition?
:STATus::PTRansition ...
:STATus::PTRansition?

" Reading and Qualifying Command Error Status
*ESE ...
*ESE?
*ESR?

" Reporting Questionable Status
:STATus:QUEStionable:CONDition:USER ...
:STATus:QUEStionable:EVENt:USER ...

! Assessing Receiver Health
*TST?
:DIAGnostic:LIFetime:COUNt?
:DIAGnostic:TEST? ...
:DIAGnostic:TEST:RESult?

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Operating Status

Receiver Operation at a Glance ___________________________

:SYSTem:STATus?
Outputs a formatted status screen.

RESPONSE FORMAT

ASCII Data

This query outputs a formatted Receiver Status screen. Use this screen to
monitor GPS acquisition, derivation of time and position, and synchronization
of reference outputs to GPS.
Refer to Chapter 3, “Visual User Interface,” for detailed information on the
Receiver Status screen.
Response

Sending this command will display a status screen similar to the following
figure (58503B screen is shown in this figure).

---------------------------- Receiver Status ---------------------------SYNCHRONIZATION .......................................... [ Outputs Valid ]
Reference Outputs
SmartClock Mode
>> Locked to GPS
TFOM
FFOM
3
0
Recovery
1PPS TI +7.2 ns relative to GPS
Holdover
HOLD THR 1.000 us
Power-up
Holdover Uncertainty
Predict 49.0 us/initial 24 hrs
ACQUISITION ................................................[GPS 1PPS Valid]
Not Tracking: 1
Tracking: 6
Time
+1 leap second pending
PRN El Az C/N
PRN El Az
UTC
23:59:59
31 Dec 1995
2
49 243
49
14 11 82
GPS 1PPS Synchronized to UTC
16 24 282
44
ANT DLY
120 ns
49
18 38 154
Position
43
19 65 52
MODE
Survey: 17.5% complete
44
27 62 327
38
31 34 61
AVG LAT N 37:19:32.264
AVG LON W 121:59:52.112
AVG HGT
+41.86 m (GPS)
ELEV MASK 10 deg
HEALTH MONITOR ...................................................... [ OK ]
Self Test: OK Int Pwr: OK Oven Pwr: OK
OCXO: OK
EFC: OK
GPS Rcv: OK

:SYSTem:STATus:LENGth?
Returns the number of lines of formatted text that are in the
Receiver Status screen.

RESPONSE FORMAT

± dd

This query returns the number of lines of formatted text that are in the
Receiver Status screen.

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Operating Status

Reading the Error Queue _________________________________

:SYSTem:ERRor?

RESPONSE FORMAT

Returns the oldest error in the Error Queue and removes that error
from the queue (first in, first out).

± dd,“XYZ”

This query returns the oldest error in the Error Queue and removes that error
from the queue (first in, first out).
See Appendix A, “Error Messages,” in this guide for detailed error information.
Response

The error response format is: , “”, where
•

The  is an integer transferred as ASCII bytes in
format (integer). The range is -32768 to 32767.

•

Negative error numbers are defined by the SCPI standard.

•

Positive error numbers are defined specifically for this Receiver.

•

An error number value of zero indicates that the Error Queue is empty.

•

The maximum length of the  is 255 characters.

Context Dependencies

:SYSTem:PRESet clears the Error Queue.
The queue is cleared (emptied) on *CLS, power-on, or upon reading the last
error from the queue.
If the Error Queue overflows, the last error in the queue is replaced with the
error -350, "Queue overflow". Any time the queue overflows, the least recent
errors remain in the queue and the most recent error is discarded.
The maximum length of the Error Queue is 30.

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Operating Status

Reading the Diagnostic Log ______________________________
The Diagnostic Log is one way to obtain Receiver status.
The following activities and events are recorded in the diagnostic log:
•

power-on sequence,

•

automatic or manual transitions between locked, and holdover,

•

automatic or manual transitions between position survey and position
hold operation,

•

alarm indications, and

•

self-test failures.

Each entry is date-and-time tagged. The log entries are stored in non-volatile
memory so all data remains valid even if power is lost. Access to the diagnostic
log entries is through commands in the :DIAGnostic:LOG subtree.
For example, to read the first diagnostic log entry, use the command
:DIAG:LOG:READ? 1

The possible log messages that can be displayed on your computer display are
listed in the following table.

Table 5-1. Diagnostic Log Messages
Log Message

Comments

Log cleared

Always becomes first log message when the log is cleared.
See :DIAG:LOG:CLEAR.

Power on

Indicates Receiver has been powered on.

Re-boot

Indicates Receiver processor has re-booted.

Survey mode started

Indicates beginning of survey for position.

Position hold mode started

Indicates transition from survey to position hold.

GPS lock started

Indicates transition into locked operation.

GPS reference valid at
yyyymmdd.hh:mm:ss

Indicates when GPS reference first become valid. Time in log is the present
time from GPS.

Holdover started, manual

Indicates transition to holdover based on user request. See
:SYNC:HOLD:INIT.

Holdover started, TI error

Indicates transition to holdover due to problem detected with Receiver
ability to properly measure interval between GPS 1 PPS and internal
oscillator 1 PPS.

Holdover started, TI limit exceeded

Indicates transition to holdover due to the interval from GPS 1 PPS to
internal oscillator 1 PPS exceeding a limit threshold for numerous
measurements.

Holdover started, not tracking GPS

Indicates transition to holdover since GPS is not tracking sufficient
satellites.

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Operating Status

Reading the Diagnostic Log ____________________ (continued)
Table 5-1. Diagnostic Log Messages (Continued)
Log Message

Comments

Holdover started, GPS RAIM alarm

Indicates transition to holdover since time RAIM algorithm has detected
GPS 1PPS timing inaccuracy.

Holdover started, GPS Alarm

Indicates transition to holdover due to GPS engine communication failure.

Holdover started, invalid GPS 1 PPS

Indicates transition to holdover due to problem with the GPS 1 PPS signal.

Holdover started, GPS

Indicates transition to holdover due to some other GPS problem.

Holdover started, HW error

Indicates transition to holdover due to internal hardware error.

Holdover started, temporary

Indicates temporary transition to holdover due to changing of certain
settings.

Holdover started

Indicates transition to holdover for any reason not covered above.

Self-test failed

Indicates self-test failed on powerup.

System preset

Indicates that the Receiver has been preset to factory settings.

Hardware failure

Indicates that a hardware failure has been detected. See Hardware Status
Register for details.

EEPROM save failed

Indicates that an attempt to save information to the EEPROM has failed.

The DIAGnostic commands for the log are described in the following text.

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Operating Status

Reading the Diagnostic Log _____________________
(continued)

:DIAGnostic:LOG:CLEar
Clears the diagnostic log.

:SYSTem:PRESet
Log is cleared

NON-VOLATILE

This command is an event that removes all previous diagnostic log entries, and
effectively sets the number of diagnostic log entries to one.

:DIAGnostic:LOG:READ:ALL?

RESPONSE FORMAT

Returns all of the most recent diagnostic log entries.

“XYZ”, ...

This query returns all of the most recent diagnostic log entries.

:DIAGnostic:LOG:CLEar . . .

:SYSTem:PRESet

Clears only the current diagnostic log.

Log is cleared

NON-VOLATILE

This command clears the diagnostic log. The optional log count parameter is
provided to ensure that no log entries are unread at the time of the clear.
Expanded Syntax
:DIAGnostic:LOG:CLEar 
Parameter

If the value sent for the optional log parameter does not match the current log
entry count (use :DIAG:LOG:COUN? to obtain this number), the clear will not
take place.
Context Dependencies

This command is always valid. If the optional log count parameter is sent, and
the current and actual log count does not match log count value, the clear will
not be performed and error -222 will be generated.

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Operating Status

Reading the Diagnostic Log _____________________
(continued)

:DIAGnostic:LOG:COUNt?

RESPONSE FORMAT

Identifies the number of entries in the diagnostic log.

± dd

This query identifies the number of entries in the diagnostic log.
Response

Range is 1 to 222, maximum is subject to change.

:DIAGnostic:LOG:READ?

RESPONSE FORMAT

Returns the most recent diagnostic log entry.

“XYZ”

This query returns the most recent diagnostic log entry.
Response

The diagnostic log entry format is: “Log NNN: YYYYMMDD.HH:MM:SS:
”, where:
Log indicates a diagnostic log entry, and NNN is the log entry number
YYYYMMDD.HH:MM:SS is the date and time of the diagnostic log entry.
The  is a sequence of up to 255 characters.

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Operating Status

Reading the Diagnostic Log _____________________
(continued)

:DIAGnostic:LOG:READ? . . .
Returns the user-specified diagnostic log entry. Returns the most
recent diagnostic log entry if no parameter is supplied.

RESPONSE FORMAT

“XYZ”

This query returns the user-specified diagnostic log entry.
Expanded Syntax
:DIAGnostic:LOG:READ? 
Parameter

Range is 1 to current log count.
Response

The diagnostic log entry format is: “Log NNN: YYYYMMDD.HH:MM:SS:
”, where:
Log indicates a diagnostic log entry, and NNN is the log entry number
YYYYMMDD.HH:MM:SS is the date and time of the diagnostic log entry.
The  is a sequence of up to 255 characters.
Context Dependencies

This query is always valid. If no log message is associated with the requested
log number, error -222 is generated.

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Operating Status

Monitoring Status/Alarm Conditions _____________________
The Receiver is at all times monitoring various operating conditions through a
status/alarm reporting system. The Receiver is shipped from the factory with
the status system set to generate an alarm under a default set of operating
conditions.
The monitored operating conditions are organized by function into three major
groups: Questionable status, Command Error status, and Operation status.
The Operation status group has three functional subgroups: Powerup status,
Holdover status, and Hardware status.
All of the operating conditions are summarized by the Alarm status.
Figure 5-1, on the next page, includes the identification of the default alarm
conditions. Those conditions which are enabled to “feed” all the way through
the system will generate an alarm in a Receiver configured with the factory
defaults. (Note a diagram identical to Figure 5-1 is provides as part of the
Receiver Commands at a Glance (cont’d)/Status Reporting System at a Glance
foldout—pages 4-17 and 4-18, respectively.)

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Operating Status

Monitoring Status/Alarm Conditions ___________ (continued)

Questionable

Binary Weights
1
0
2
1
4
2
8
3
4 16
5 32
6 64
7 128

0
1

8
256
9
512
10 1024
11 2048
12 4096
13 8192
14 16384
15 32768

"OR"

Time Reset
User-reported

Alarm
Command Error

not used
not used

not used

3

not used

2
3
4
5

Query Error
Hardware/Firmware Error
Semantic Error
Syntactic Error

"OR"
5
6
7

not used

7

Powerup
0
1
2

0
1
2

Holdover
0
1
2
3

Holding
Waiting to Recover
Recovering
Exceeding Threshold

0
1
2
3
4

Selftest Failure
+15V Supply Exceeds Tolerance
-15V Supply Exceeds Tolerance
+5V Supply Exceeds Tolerance
Oven Supply Exceeds Tolerance

6
7
8
9
10
11
12

EFC Voltage Near Full-Scale
EFC Voltage Full-Scale
GPS 1 PPS Failure
GPS Failure
TI Measurement Failed
EEPROM Write Failed
Internal Reference Failure

"OR"

Questionable Summary
not used

Alarm

Command Error Summary
Master Summary
Operation Summary

Power Cycled

Operation

"OR"

First Satellite Tracked
Oscillator Oven Warm
Date & Time Valid

"OR"

not used

3
4
5
6

Powerup Summary
Locked
Holdover Summary
Position Hold
1 PPS Reference Valid
Hardware Summary
Log Almost Full

"OR"

Hardware

not used

"OR"

Shading identifies
summary bit.

Powerup Summary
Default Transition Filter

Default Event Enable

False-to-true (positive)
transition latches event.

Event enabled to report to
summary bit.

Not applicable

Event disabled

Figure 5-1. 59551A/58503B Status Reporting System Diagram

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Chapter 5 Command Reference
Operating Status

Monitoring Status/Alarm Conditions ___________ (continued)
The following describes, for each functional group of operating status shown in
Figure 5-1, each of the operating conditions that is monitored through the
status/alarm system.
Each monitored condition bit is “set” (to one) when the named condition is true
and “cleared” (to zero) when the named condition is false.
Each monitored event bit is set when the named event has occurred and
cleared at powerup and when the user executes a command which reads or
clears the event register.
All of the conditions and events are cleared at powerup and :SYSTem:PRESet.

Alarm Status
The Alarm Status summarizes condition changes from the three major
functional status groups (Questionable, Command Error, and Operation).
•

The Questionable Summary condition (bit 3) reflects one or more latched
condition changes in the Questionable status group.

•

The Command Error Summary condition (bit 5) reflects one or more
latched condition changes in the Command Error status group.

•

The Master Summary condition (bit 6) indicates that there was at least
one reason for generating an Alarm.

•

The Operation Summary condition (bit 7) reflects one or more latched
condition changes in the Operation status group.

Operation Status
The Operation Status is comprised of the Operation subgroup (Powerup,
Holdover, and Hardware) summaries, Locked, Position Hold, 1 PPS Reference
Valid, and Log Almost Full status.
•

The Powerup Summary condition (bit 0) reflects one or more latched
condition changes in the Powerup status group.

•

The Locked condition (bit 1) indicates whether or not the Receiver is
locked to GPS.

•

The Holdover Summary condition (bit 2) reflects one or more latched
condition changes in the Holdover status group.

•

The Position Hold condition (bit 3) indicates whether the Receiver is in
position hold or survey mode.

•

The 1 PPS Reference Valid condition (bit 4) indicates that the GPS 1 PPS
signal is suitable to use as a locking reference.

•

The Hardware Summary condition (bit 5) reflects one or more latched
condition changes in the Hardware status group.

•

The Log Almost Full condition (bit 6) indicates whether or not the
diagnostic log is approaching the point where new entries will no longer be
logged.

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Chapter 5 Command Reference
Operating Status

Monitoring Status/Alarm Conditions ___________ (continued)
Hardware Status
This Operation subgroup comprises operating status that indicates the health
of the Receiver hardware.
One or more of the condition changes from this group are summarized in the
Operation Status group.
•

The Selftest Failure condition (bit 0) indicates whether a failure was
detected during the powerup or last user-initiated self-test.

•

The following conditions reflect the status of specific hardware that is
continuously monitored by the Receiver:

•

+15V Supply Exceeds Tolerance condition

(bit 1)

−15V Supply Exceeds Tolerance condition

(bit 2)

+5V Supply Exceeds Tolerance condition

(bit 3)

Oven Supply Exceeds Tolerance condition

(bit 4)

EFC Voltage Near Full-Scale condition

(bit 6)

EFC Voltage Full-Scale condition

(bit 7)

GPS 1 PPS Failure condition

(bit 8)

GPS Failure condition

(bit 9)

Time Interval Measurement Failed event

(bit 10)

Internal Reference Failure condition

(bit 12)

The EEPROM Write Failed event (bit 11) indicates that an attempt to
write to the non-volatile memory failed.

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Chapter 5 Command Reference
Operating Status

Monitoring Status/Alarm Conditions ___________ (continued)
Holdover Status
This Operation subgroup is comprised of operating status that occurs during
holdover.
One or more of the condition changes from this group are summarized in the
Operation Status group.
•

•

The following conditions indicate that the Receiver is in holdover, and the
specific holdover state:
Holding condition

(bit 0)

Waiting to Recover condition

(bit 1)

Recovering condition

(bit 2)

The Exceeding User-Threshold condition (bit 3) indicates whether or not
the user-specified holdover duration
(:SYNC:HOLDover:DURation:THReshold) is being exceeded.

Powerup Status
This Operation subgroup is comprised of operating status that occurs at
powerup.
One or more of the condition changes from this group are summarized in the
Operation Status group.
•

The First Satellite Tracked condition (bit 0) is cleared at powerup and set
when the first satellite becomes tracked following powerup.

•

The Oscillator Oven Warm condition (bit 1) is cleared at powerup and set
when the internal oscillator has warmed up following powerup.

•

The Date & Time Valid event (bit 2) is cleared at powerup and set when
the date and time are set during the first lock is attained after powerup.

Questionable Status
The Time Reset status event (bit 0) indicates that the Receiver reset its time
because the Receiver's time was found to be different from the time being
reported by the satellites. This could occur after an extensive holdover period.
The User-reported condition (bit 1) indicates the setting reported by the user
with the :STATus:QUEStionable:CONDition:USER or
:STATus:QUEStionable:EVENt:USER command. This is the only condition in
the status/alarm reporting that the user can directly affect.

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Operating Status

Monitoring Status/Alarm Conditions ___________ (continued)
Command Error Status
This group contains events which indicate a command error has occurred, and
an event which indicates that the power has cycled. (See Figure 5-1.)
The following status events indicate that a command error occurred:
•

The Query Error status event (bit 2). Errors -400 through -499 are query
errors.

•

The Hardware/Firmware Error status event (bit 3). Errors -300 through
-399 are hardware/firmware errors.

•

The Semantic Error status event (bit 4). Errors -200 through -299 are
semantic errors.

•

The Syntactic Error status event (bit 5). Errors -100 through -199 are
syntactic errors.

•

The Power Cycled status event (bit 7) is set at powerup.

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Operating Status

Monitoring Status/Alarm Conditions ___________ (continued)
! Clearing and Presetting Alarms ______________________________

*CLS
Clears the current alarm and prepares the Receiver for the next
alarm activation.

EVENT

When the *CLS command clears the event status registers and error queue, the
Receiver’s Alarm LED and Alarm BITE output will no longer indicate that
there was a reason to alarm. Furthermore, the Receiver is then ready to detect
a new alarm.
Context Dependencies

In the 59551A, the error queue (and corresponding serial port prompt) of the
I/O port which transmitted *CLS will be cleared.
Side Effects

The Alarm LED is extinguished.
The Alarm BITE output is set “inactive/off.”
The prompt of the serial I/O port (which transmits *CLS) reflects error queue
clearing.
The event status registers are cleared.
The error queue (and corresponding serial port prompt) of the I/O port which
transmitted *CLS will be cleared.
Theory

The *CLS command clears the event status registers and error queue.
(They are also cleared at power-up.)
Since the Alarm Condition register summarizes the event registers, it is
cleared as a result of the clearing of all of the event registers.
The alarm remains active even after the condition that caused it has gone
away.
If the condition that caused the alarm to occur is still set, a new alarm cannot
be detected until the condition clears and resets.
This command has no effect on condition, enable, or transition filter registers.

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Operating Status

Monitoring Status/Alarm Conditions ___________ (continued)
! Clearing and Presetting Alarms (continued)

:STATus:PRESet:ALARm
Presets the status/alarm reporting system to generate an alarm
when a factory default set of operating conditions occurs.

EVENT

When the configurable portion of the status/alarm reporting system is preset,
the Receiver is configured to generate an alarm under the factory default set of
operating conditions.
Use this command to restore only the status/alarm reporting system to the
factory (:SYSTem:PRESet) settings.
Theory

The configurable portion of the status/alarm reporting system consists of
enable and transition filter registers. Figure 5-1 identifies the factory default
enables and transitions.
The status/alarm reporting configuration is stored in non-volatile memory.
This command performs a subset of the :SYSTem:PRESet command in that it
only presets the configuration associated with status/alarm reporting system.
This command does not affect condition or event registers.

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Operating Status

Monitoring Status/Alarm Conditions ___________ (continued)
! Reading and Qualifying Alarms _____________________________

Alarm
Condition
Register
not used
not used
not used

STB?

*

3

Questionable Summary
not used

5
6
7

Command Error Summary
Master Summary
Operation Summary

"AND"

&

Alarm
Enable
Register

"OR"

&

:LED:ALARm?
Alarm

not used
not used

&

not used

*SRE 
*SRE?

3

Questionable Summary
not used

5

Command Error Summary
not used

7

Operation Summary

Figure 5-2. Alarm Condition and Enable Registers

:LED:ALARm?

RESPONSE FORMAT

Returns the status of the front-panel Alarm LED.

0 or 1

This query returns the status of the front-panel Alarm LED, which indicates
that a change in operating conditions was recorded. The alarm remains active
even after the condition that caused it has gone away.
Theory

This query essentially reads the Master Summary bit (bit 6) of the Alarm
Condition Register.
At power-up, the alarm status is cleared.

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Operating Status

Monitoring Status/Alarm Conditions ___________ (continued)
! Reading and Qualifying Alarms (continued)

*SRE . . .
Sets the Alarm Enable Register.

:SYSTem:PRESet

136
NON-VOLATILE

The setting of the Alarm Enable Register (Figure 5-2) selects which summary
status from the Alarm Condition Register is enabled to generate an alarm.
Expanded Syntax
*SRE 
Semantics

The  has a range of 0 to 255.
The  value represents the sum of the binary-weighted values of the
register. Attempts to set unused bits in the register are ignored—the value of
unused bits is zero.

*SRE?
Identifies the status conditions enabled to generate an alarm.

RESPONSE FORMAT

± dd

This query identifies the status conditions enabled to generate an alarm.
Reading the Alarm Enable Register identifies which summary status from the
Alarm Condition Register is enabled to generate an alarm.
Response

The range is 0 to 255.
The response value represents the sum of the binary-weighted values of the
register. The value of unused bits is zero.
Theory

Reading/Querying the Alarm Enable Register does not change its contents.

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Chapter 5 Command Reference
Operating Status

Monitoring Status/Alarm Conditions ___________ (continued)
! Reading and Qualifying Alarms (continued)

*STB?

RESPONSE FORMAT

Reads the Alarm Condition Register.

± dd

This query reads the Alarm Condition Register (Figure 5-2).
Response

The range is 0 to 255.
The response value represents the sum of the binary-weighted values of the
register. The value of unused bits is zero.
Theory

The Alarm Condition Register continuously monitors the summary status of
the instrument.
The Alarm Condition Register bits are updated in real time—there is no
latching or buffering.
Reading/Querying the Alarm Condition Register does not change its contents.
At powerup, the Alarm Condition Register is cleared.

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Operating Status

Monitoring Status/Alarm Conditions ___________ (continued)
! Reading and Qualifying Receiver Status ____________________
Condition
Register

Transition
Filter

Event
Register

0
1
2

*
*
*

0
1
2

"AND"

&
n
Continuously monitors
conditions
:STATus::CONDition?

n

*
Enables condition changes to
report to Event Register
:STATus::PTR . . .
:STATus::PTR?
:STATus::NTR . . .
:STATus::NTR?

&
Latches condition changes
:STATus::EVENt?

&

Event
Enable
Register

&

"OR"
Summary
Bit

0
1
2

*=

positive transition or
negative transition or
either transition or

n

neither transition
 = OPERation or
QUEStionable or
OPERation:HARDware or
OPERation:HOLDover or
OPERation:POWerup

Enables events to
report to summary bit
:STATus::ENABle 
:STATus::ENABle?

Figure 5-3. Condition, Transition Filter, Event Enable, and Event
Registers

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Chapter 5 Command Reference
Operating Status

Monitoring Status/Alarm Conditions ___________ (continued)
! Reading and Qualifying Receiver Status (continued)

:STATus::CONDition?

RESPONSE FORMAT

Reads the specified condition register.

± dd

This query reads the specified condition register (figures 5-3 and 5-1).
Expanded Syntax
:STATus:OPERation:CONDition?
:STATus:QUEStionable:CONDition?
:STATus:OPERation:HARDware:CONDition?
:STATus:OPERation:HOLDover:CONDition?
:STATus:OPERation:POWerup:CONDition?
Response

The range is 0 to 65535.
The response value represents the sum of the binary-weighted values of the
register. The value of unused bits is zero.
Note that some bits, those which are “event-only”, have no corresponding
conditions.
Theory

A condition register continuously monitors the hardware and firmware status
(that is, the operating conditions) of the instrument.
Conditions register bits are updated in real time—there is no latching or
buffering.
Reading/Querying a condition register does not change its contents.
At powerup, the conditions registers are cleared.

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Operating Status

Monitoring Status/Alarm Conditions ___________ (continued)
! Reading and Qualifying Receiver Status (continued)

:STATus::EVENt?
Reads the specified event register.

RESPONSE FORMAT

± dd

This query reads the specified event register (figures 5-3 and 5-1), retrieving
information about what has happened to the instrument since it was last
queried, or cleared by :SYSTem:PRESet or *CLS.
Expanded Syntax
:STATus:OPERation:EVENt?
:STATus:QUEStionable:EVENt?
:STATus:OPERation:HARDware:EVENt?
:STATus:OPERation:HOLDover:EVENt?
:STATus:OPERation:POWerup:EVENt?
Response

The range is 0 to 65535.
The response value represents the sum of the binary-weighted values of the
register. The value of unused bits is zero.
Side Effects

Reading/Querying an event register clears it.
Theory

An event register captures changes in conditions. When a transition occurs, the
corresponding bit in the event register is set TRUE. The instrument can be
configured (using :STATus::NTRansition and
:STATus::PTRansition), for each bit position, to capture the positive,
the negative, either, or neither transition.
Event register bits, once set, are latched. That is, they remain set until they are
read. When they are read, they are cleared.
At powerup, the event registers are cleared.
See Also
:STATus::NTRansition . . .
:STATus::PTRansition . . .

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Operating Status

Monitoring Status/Alarm Conditions ___________ (continued)
! Reading and Qualifying Receiver Status (continued)

:STATus::ENABle . . .

:SYSTem:PRESet

Sets the specified enable register.

See Figure 5-1 for Default
Event Enable identification
NON-VOLATILE

The setting of an enable register (figures 5-3 and 5-1) selects which events from
the corresponding event register are enabled to report to the corresponding
summary bit of the summarizing condition register.
Expanded Syntax
:STATus:OPERation:ENABle 
:STATus:QUEStionable:ENABle 
:STATus:OPERation:HARDware:ENABle 
:STATus:OPERation:HOLDover:ENABle 
:STATus:OPERation:POWerup:ENABle 
Parameter

The  has a range of 0 to 65535.
The  value represents the sum of the binary-weighted values of the
register. Attempts to set unused bits in an enable register are ignored—the
value of unused bits is zero.

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Operating Status

Monitoring Status/Alarm Conditions ___________ (continued)
! Reading and Qualifying Receiver Status (continued)

:STATus::ENABle?
Reads the specified enable register.

RESPONSE FORMAT

± dd

Reading an enable register (figures 5-3 and 5-1) identifies which events from
the corresponding event register are enabled to report to the corresponding
summary bit of the summarizing condition register.
Expanded Syntax
:STATus:OPERation:ENABle?
:STATus:QUEStionable:ENABle?
:STATus:OPERation:HARDware:ENABle?
:STATus:OPERation:HOLDover:ENABle?
:STATus:OPERation:POWerup:ENABle?
Response

The range is 0 to 65535.
The response value represents the sum of the binary-weighted values of the
register. The value of unused bits is zero.
Theory

Reading/Querying an enable register does not change its contents.

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Operating Status

Monitoring Status/Alarm Conditions ___________ (continued)
! Reading and Qualifying Receiver Status (continued)

:STATus::NTRansition . . .
:STATus::PTRansition . . .

:SYSTem:PRESet

Sets the specified transition filter registers.

See Figure 5-1 for Default
Transition Filter
identification
NON-VOLATILE

The setting of the transition filter registers selects which condition transitions
(positive, negative, either, or neither) are enabled to report events.
Expanded Syntax
:STATus:OPERation:NTRansition 
:STATus:QUEStionable:NTRansition 
:STATus:OPERation:HARDware:NTRansition 
:STATus:OPERation:HOLDover:NTRansition 
:STATus:OPERation:POWerup:NTRansition 
:STATus:OPERation:PTRansition 
:STATus:QUEStionable:PTRansition 
:STATus:OPERation:HARDware:PTRansition 
:STATus:OPERation:HOLDover:PTRansition 
:STATus:OPERation:POWerup:PTRansition 
Parameter

The  has a range of 0 to 65535.
The  value represents the sum of the binary-weighted values of the
register. Attempts to set unused bits in the transition filter are ignored—the
value of unused bits is zero.
To enable negative (one to zero) transitions of specific conditions, set the
corresponding bits to one in the  for the NTRansition register
command.
To enable positive (zero to one) transitions of specific conditions, set the
corresponding bits to one in the  for the PTRansition register
command.
Note that some bits, those which are “event-only”, have no transition filter
setting. Attempts to set these bits are ignored.

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Operating Status

Monitoring Status/Alarm Conditions ___________ (continued)
! Reading and Qualifying Receiver Status (continued)

:STATus::NTRansition?
:STATus::PTRansition?
Reads the specified transition filter registers.

RESPONSE FORMAT

± dd

Reading the transition filter registers identifies which condition transitions
(positive, negative, either, or neither) are enabled to report events.
Expanded Syntax
:STATus:OPERation:NTRansition?
:STATus:QUEStionable:NTRansition?
:STATus:OPERation:HARDware:NTRansition?
:STATus:OPERation:HOLDover:NTRansition?
:STATus:OPERation:POWerup:NTRansition?
:STATus:OPERation:PTRansition?
:STATus:QUEStionable:PTRansition?
:STATus:OPERation:HARDware:PTRansition?
:STATus:OPERation:HOLDover:PTRansition?
:STATus:OPERation:POWerup:PTRansition?
Response

The range is 0 to 65535.
The response value represents the sum of the binary-weighted values of the
register. The value of unused bits is zero.
The bits which are set to one in the  of the NTRansition query
response indicate the enabled negative transitions of corresponding conditions.
The bits which are set to one in the  of the PTRansition query
response indicate the enabled positive transitions of corresponding conditions.
Theory

Reading/Querying a transition filter register does not change its contents.

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Operating Status

Monitoring Status/Alarm Conditions ___________ (continued)
! Reading and Qualifying Command Error Status ____________

Command Error
Event
Register
not used
not used

ESR?

*

2
3
4
5

Query Error
Hardware/Firmware Error
Semantic Error
Syntactic Error

7

Power Cycled

"AND"
&

not used

Command Error
Enable
Register

&
"OR"
&

Command Error
Summary Bit of
Alarm Condition
Register

not used
not used

ESE 
ESE?

*
*

2
3
4
5

Query Error
Hardware/Firmware Error
Semantic Error
Syntactic Error

&

&

not used

7

Power Cycled

Figure 5-4. Command Error Event and Enable Registers

*ESE . . .
Sets the Command Error Enable Register.

:SYSTem:PRESet

0
NON-VOLATILE

The setting of the Command Error Enable Register (Figure 5-4) selects which
events from the Command Error Event Register are enabled to report to the
Command Error Summary bit of the Alarm Condition Register.
Expanded Syntax
*ESE 
Parameter

The  has a range of 0 to 255.
The  value represents the sum of the binary-weighted values of the
register. Attempts to set unused bits in the register are ignored—the value of
unused bits is zero.

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Operating Status

Monitoring Status/Alarm Conditions ___________ (continued)
! Reading and Qualifying Command Error Status (continued)

*ESE?
Reads the Command Error Enable Register.

RESPONSE FORMAT

± dd

This query identifies the status conditions enabled to generate an alarm.
Reading the Command Error Enable Register (Figure 5-4) identifies which
events from the Command Error Event Register are enabled to report to the
Command Error Summary bit of the Alarm Condition Register.
Response

The range is 0 to 255.
The response value represents the sum of the binary–weighted values of the
register. The value of unused bits is zero.
Theory

Reading/Querying the Command Error Enable Register does not change its
contents.

*ESR?
Reads the Command Error Event Register.

RESPONSE FORMAT

± dd

This query reads the Command Error Event Register, retrieving information
about errors (or power cycles) that have occurred since the instrument was last
queried, or cleared by SYSTem:PRESet or *CLS.
Response

The range is 0 to 255.
The response value represents the sum of the binary-weighted values of the
register. The value of unused bits is zero.

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Operating Status

Monitoring Status/Alarm Conditions ___________ (continued)
! Reporting Questionable Status ____________________________

:STATus:QUEStionable:CONDition:USER . . .
Sets the User-reported bit of the Questionable Condition Register.

:SYSTem:PRESet

Clear
NON-VOLATILE

This command sets the User-reported bit of the Questionable Condition
Register.
Expanded Syntax
:STATus:QUEStionable:CONDition:USER SET or CLEar
Parameter

SET will cause the User-reported bit of Questionable Condition Register to be
set to 1.
CLEar will cause the User-reported bit of Questionable Condition Register to
be set to 0.
Side Effects

The User-reported bit of the Questionable Condition Register is set or cleared
by this command.
Theory

A condition change (from SET to CLEAR, or CLEAR to SET) of the Userreported bit of the Questionable Condition Register, and the appropriate
configuration of the Questionable Transition Filter is necessary to generate an
event in the Questionable Event Register.
Furthermore, when the User-reported bit of Questionable Event Enable
Register is enabled, and the Questionable Summary bit of the Alarm Enable
Register is enabled, then a transition of the User-reported condition will
generate an ALARM.

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Operating Status

Monitoring Status/Alarm Conditions ___________ (continued)
! Reporting Questionable Status (continued)

:STATus:QUEStionable:EVENt:USER . . .
Generates a transition of the User-reported bit of the Questionable
Condition Register.

EVENT
NON-VOLATILE

This command generates a transition of the User-reported bit of the
Questionable Condition Register.
Expanded Syntax
:STATus:QUEStionable:EVENt:USER PTRansition or NTRansition
Parameter

PTRansition will cause the User-reported bit of Questionable Condition
Register to transition from a setting of 0 to a setting of 1.
NTRansition will cause the User-reported bit of Questionable Condition
Register to transition from a setting of 1 to a setting of 0.
Context Dependencies

Issuing PTRansition, while the User-reported bit of the Questionable Positive
Transition Register is enabled, sets the User-reported bit of the Questionable
Event register.
Issuing NTRansition, while the User-reported bit of the Questionable Negative
Transition Register is enabled, sets the User-reported bit of the Questionable
Event register.
Side Effects

The user-reported bit of the Questionable Condition Register is set by the
PTRansition parameter or cleared by the NTRansition parameter.
Theory

A positive or negative (PTRansition or NTRansition) of the User-reported bit of
the Questionable Condition Register, and the appropriate configuration of the
Questionable Transition Filter is necessary to generate an event in the
Questionable Event Register.
Furthermore, when the User-reported bit of Questionable Event Enable
Register is enabled, and the Questionable Summary bit of the Alarm Enable
Register is enabled, then a User-reported event will generate an ALARM.

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Operating Status

Assessing Receiver Health ________________________________

*TST?

RESPONSE FORMAT

Executes an internal selftest and reports the results.

± dd

This query causes an internal selftest and the response indicates whether any
errors were detected. This test takes about 40 seconds to complete.
Error -330, “Self test failed” is generated if the selftest fails.
NOTE

Manual operation of internal diagnostics will affect normal Receiver
operation, including disruption of any or all of the following: GPS satellite
tracking, reference oscillator frequency, 1 PPS output timing, and Receiver
status information. When invoked manually, any of these diagnostics should
be considered to be destructive tests.
The following elements and functions are tested:
CPU
EPROM
RAM
EEPROM
UART
QSPI
FPGA logic
Interpolators
GPS engine
Power supply levels
Reference oscillator
Response

A value of 0 indicates the tests passed, a non-zero value indicates the selftest
was not completed or was completed with errors detected.

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Operating Status

Assessing Receiver Health ______________________ (continued)

:DIAGnostic:LIFetime:COUNt?
Returns the lifetime count, indicating the total powered-on time.

RESPONSE FORMAT

± dd

This query returns the lifetime count, indicating the total powered-on time.
Response

Range of the integer is 0 to 4,294,967,296 with a resolution of 1. Each count
represents three hours of operation.

:DIAGnostic:TEST? . . .
Returns information for user-specified test.

RESPONSE FORMAT

± dd

This query returns information for user-specified test.
Expanded Syntax
:DIAGnostic:TEST? ALL or DISPlay or PROCessor or RAM or EEPRom or UART or QSPI
or FPGA or INTerpolator or GPS or POWer.
Response

A value of 0 (zero) indicates test passed.
Parameter

ALL returns test information for all of the tests.

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Operating Status

Assessing Receiver Health ______________________ (continued)

:DIAGnostic:TEST:RESult?

RESPONSE FORMAT

Returns the result of the last test and the type of test performed.

± dd, XYZ

This query returns the result of the last test and the type of test performed.
Use this query, for example, following powerup to check the outcome of the
powerup selftest.
Response

A value of 0 indicates test passed. Non-zero value indicates test failed.
The literal or alphanumeric characters portion of the response identifies the
specific test.

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System Time

System Time
The GPS Receiver is designed to allow you access to a very accurate system
clock that provides both date and time, to customize the clock for a local time
zone, to identify the exact time, to identify the accumulated time difference (in
seconds) between the GPS and UTC timelines, and to monitor and adjust for
leap second occurrences.
The following commands are provided to allow you to monitor and control the
system date and time.
" Identifying Time of Next 1 PPS Reference Edge
:PTIMe:TCODe?

" Reading Current Time
:PTIMe:DATE?
or
:PTIMe:TIME?
or
:PTIMe:TIME:STRing?

:SYSTem:DATE?
:SYSTem:TIME?

" Applying Local Time Zone Offset
:PTIMe:TZONe ...
:PTIMe:TZONe?

" Defining the 1 PPS Reference Edge (59551A Only)
:PTIMe:PPS:EDGE ...
:PTIMe:PPS:EDGE?

" Reading Leap Second Status
:PTIMe:LEAPsecond:ACCumulated?
:PTIMe:LEAPsecond:DATE?
:PTIMe:LEAPsecond:DURation?
:PTIMe:LEAPsecond:STATe?

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System Time

Identifying Time of Next 1 PPS Reference Edge __________

:PTIMe:TCODe?

RESPONSE FORMAT

Returns timecode message 980 to 20 ms prior to 1 PPS of
indicated time.

ASCII Data

This query returns timecode message 980 to 20 ms prior to 1 PPS of indicated
time. This special query provides not only accurate time but also provides the
user the opportunity to correctly correlate this time with a corresponding
1 PPS edge.
Response

The query response provides the following type of information:
•

date and time of next on-time edge,

•

Time Figure of Merit,

•

Frequency Figure of Merit,

•

leap second indicator,

•

alarm indication, and

•

service request.

An example response is:
T2199505112055233000049
This example is in the "T2YYYYMMDDHHMMSSMFLRVcc" format, where
T2

indicates a timecode message.

YYYYMMDD is the calendar date at the next 1 PPS on-time edge.
HHMMSS

is the 24 hour time at the next 1 PPS on-time edge.
Note that this value is influenced by the ptim:tzon setting.

M

is time figure of merit.

F

is frequency figure of merit.

L

is leapsecond indicator (- means a -1 leapsecond is pending,
0 means no leapsecond pending, + means a 1 leapsecond is
pending).

R

is the request for service bit from the status system (0 = no
service requested, 1 = service requested). An alarm will be
generated when this byte transitions to 1.

V

is validity byte. 1 indicates that time-related information isn't
valid, 0 indicates that it is valid.

cc

is the checksum of the prior bytes (two Hex bytes).

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System Time

Reading Current Time____________________________________

:PTIMe:DATE?
:SYSTem:DATE?
Returns the current calendar date.

RESPONSE FORMAT

± dd, ± dd, ± dd

This query returns the current calendar date. The local calendar date is always
referenced to UTC time, offset by any local time zone value that has been
provided by the user. The year, month, and day are returned.
Response

Three fields are separated by commas: ,,.
•

The  range is 1994 to 2077.

•

The  range is 1 to 12.

•

The  range is 1 to 31.

Context Dependencies

This query is not valid prior to the first lock following powerup (see bit 2 of the
Powerup Status Register) or :SYSTem:PRESet. Sending this query before the
first lock will generate error -230.

:PTIMe:TIME?
:SYSTem:TIME?
Returns the current 24-hour time.

RESPONSE FORMAT

± dd, ± dd, ± dd

This query returns the current 24-hour time. The local time is always
referenced to UTC time, offset by any local time zone value that has been
provided by the user. The hour, minute, and second is returned.
Response

Three fields are separated by commas: ,,.
•

The  range is 0 to 23.

•

The  range is 0 to 59.

•

The  range is 0 to 60. The value of 60 only occurs as the UTC
leapsecond.

Context Dependencies

This query is not valid prior to the first lock following powerup (see bit 2 of the
Powerup Status Register) or :SYSTem:PRESet. Sending this query before the
first lock will generate error -230.

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System Time

Reading Current Time__________________________ (continued)

:PTIMe:TIME:STRing?

RESPONSE FORMAT

Returns the current 24-hour time suitable for display.

“XYZ”

This query returns the current 24-hour time suitable for display (for example,
15:23:06).
Context Dependencies

This query is not valid prior to the first lock following powerup (see bit 2 of the
Powerup Status Register) or :SYSTem:PRESet. Sending this query before the
first lock will generate error -230.

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System Time

Applying Local Time Zone Offset _________________________

:PTIMe:TZONe . . .
Sets the time zone local time offset to provide an offset from UTC
to serve as the basis for all reported time.

:SYSTem:PRESet

0,0
NON-VOLATILE

This command sets the time zone local time offset to provide an offset from
Universal Coordinated Time (UTC) to serve as the basis for all reported time.
The local 24-hour time and local calendar date depend on the present setting
of the time zone parameter, which is used to indicate the offset from UTC.
Typical application of this command is to account for time zone differences
between the installed Receiver location and the prime meridian at Greenwich,
which uses UTC uncorrected.
Expanded Syntax
:PTIMe:TZONe , 
Parameter

•

The  range is -12 to +12, and is rounded to the nearest integer.

•

The optionally supplied  range -59 to +59, and is rounded to the
nearest integer. The  is defaulted to 0 if not supplied.

Context Dependencies

:SYSTem:PRESet sets the time zone to zero (0,0).

:PTIMe:TZONe?
Returns the local time zone offset.

RESPONSE FORMAT

± dd, ± dd

This query returns the local time zone offset.
Response

The first returned value is offset hours. The second returned value is offset
minutes.

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System Time

Defining the 1 PPS Reference Edge (59551A Only) ____
59551A

:PTIMe:PPS:EDGE . . .

:SYSTem:PRESet

Selects the polarity of the 1 PPS on-time edge.

RISing
NON-VOLATILE

This command selects the polarity of the 1 PPS on-time edge.
Expanded Syntax
:PTIMe:PPS:EDGE RISing or FALLing
Parameter

The RISing parameter sets the 1 PPS rising edge as the on-time edge.
The FALLing parameter sets the 1 PPS falling edge as the on-time edge.

59551A

:PTIMe:PPS:EDGE?

RESPONSE FORMAT

Returns the polarity of the 1 PPS on-time edge.

XYZ

This query returns the polarity of the 1 PPS on-time edge.
Response

RIS indicates that the 1 PPS on-time edge is the rising edge.
FALL indicates that the 1 PPS on-time edge is the falling edge.

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System Time

Reading Leap Second Status ______________________________

:PTIMe:LEAPsecond:ACCumulated?
Returns the leap second difference accumulated between GPS
time and UTC time since the beginning of GPS time. The time
units are seconds.

RESPONSE FORMAT

± dd

This query returns the leap second difference accumulated between GPS time
and UTC time since the beginning of GPS time. The time units are seconds.
Response

An example response is:
+10
which indicates that the accumulated leap second difference between the GPS
time and UTC is 10 seconds.
Context Dependencies

This query is not valid prior to the first lock following powerup (see bit 2 of the
Powerup Status Register) or :SYSTem:PRESet. Sending this query before the
first lock will generate error -230.
Theory

The leap second value is initialized during the power-on sequence by
evaluating :PTIMe:LEAPsecond:ACC = GPS time - UTC time. In July 1994,
the value was 10 seconds.
The value is automatically adjusted immediately following the occurrence of a
leap second correction to the UTC time scale. When a 1 leap second addition is
made to the UTC time scale, the extra second delays the arrival of midnight
UTC causing :PTIM:LEAP:ACC? to increase by 1 second. When a 1 leap second
subtraction is made to the UTC time scale, the missing second hastens the
arrival of UTC midnight causing :PTIM:LEAP:ACC? to decrease by 1 second.

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System Time

Reading Leap Second Status ____________________ (continued)

:PTIMe:LEAPsecond:DATE?

RESPONSE FORMAT

Returns the UTC calendar date of next leap second.

± dd, ± dd, ± dd

This query returns the UTC calendar date of next leap second. The year,
month, and day are returned.
Response

Three fields are separated by commas: ,,.
•

The  range is 1994 to 2077.

•

The  range is 1 to 12.

•

The  range is 1 to 31.

Context Dependencies

This query is not valid prior to the first lock following powerup (see bit 2 of the
Powerup Status Register) or :SYSTem:PRESet, or if no leap second is pending.
Sending this query before the first lock or if no leap second is pending will
generate error -230.

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System Time

Reading Leap Second Status ____________________ (continued)

:PTIMe:LEAPsecond:DURation?

RESPONSE FORMAT

Returns the duration of the minute corrected by the next leap
second.

± dd

This query identifies whether a leap second is pending, distinguishes between
leap seconds which extend the minute, and leap seconds which shorten the
minute. This query returns the duration of the minute corrected by the next
leap second. The duration units are seconds.
Response

Returns a value of 59, 60 or 61:
•

A value of 59 indicates subtraction of 1 second is pending.

•

A value of 60 indicates no leap second pending.

•

A value of 61 indicates addition of 1 second is pending.

Context Dependencies

This query is not valid prior to the first lock following powerup (see bit 2 of the
Powerup Status Register) or :SYSTem:PRESet, or if no leap second is pending.
Sending this query before the first lock or if no leap second is pending will
generate error -230.

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System Time

Reading Leap Second Status ____________________ (continued)

:PTIMe:LEAPsecond:STATe?

RESPONSE FORMAT

Identifies if leap second is pending.

0 or 1

This query identifies if a leap second is pending. This query looks ahead to
indicate a pending leap second.
Response

A value of 0 indicates no leap second is pending.
A value of 1 indicates a leap second is pending. The leap second adjustment can
be either the addition of a second or the subtraction of a second.
Context Dependencies

This query is not valid prior to the first lock following powerup (see bit 2 of the
Powerup Status Register) or :SYSTem:PRESet (but is valid if no leap second is
pending). Sending this query before the first lock will generate error -230.

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Programmable Pulse Output (59551A Only)

Programmable Pulse Output
(59551A Only)
The Programmable Pulse output feature provides a means of using the GPS
Receiver as a pulse generator. The pulse output, which is programmable by the
user, can either generate a stream of pulses at a specified start time and
repetition interval, or it can produce a single pulse at a specified time and then
stop.
The following commands are provided to allow you to operate and control the
programmable output of the 59551A GPS Receiver.
Note that the configuring of the Programmable Pulse output requires
consideration of five settings: start date, start time, continuous on/off, pulse
period, and pulse polarity. Changing any one of the settings will stop any
previously configured pulse stream and reassert all five settings. If the start
date has already passed when you modify the repetition interval, the pulse
output will halt until you provide a new start date.

:PULSe:CONTinuous:PERiod ...
:PULSe:CONTinuous:PERiod?
:PULSe:CONTinuous:STATe ...
:PULSe:CONTinuous:STATe?
:PULSe:REFerence:EDGE ...
:PULSe:REFerence:EDGE?
:PULSe:STARt:DATE ...
:PULSe:STARt:DATE?
:PULSe:STARt:TIME ...
:PULSe:STARt:TIME?

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Programmable Pulse Output (59551A Only)

59551A

:PULSe:CONTinuous:PERiod . . .

:SYSTem:PRESet

Sets the interval between pulses in seconds.

1
NON-VOLATILE

This command sets the interval between pulses in seconds.
Expanded Syntax
:PULSe:CONTinuous:PERiod 
Parameter

The  parameter range is 1 to 31536000, equivalent to one year.
Resolution is 1.
Context Dependencies

The interval set by this command is only used if :PULSe:CONTinuous:STATe
is ON.

59551A

:PULSe:CONTinuous:PERiod?

RESPONSE FORMAT

Returns the interval between pulses in seconds.

± dd

This query returns the interval between pulses in seconds.

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Programmable Pulse Output (59551A Only)

59551A

:PULSe:CONTinuous:STATe . . .
Controls whether the Programmable Pulse output will be just one
pulse or a sequence of pulses.

:SYSTem:PRESet

OFF
NON-VOLATILE

This command controls whether the Programmable Pulse output will be just
one pulse or a sequence of pulses.
Expanded Syntax
:PULSe:CONTinuous:STATe ON or OFF
Parameter

OFF selects one pulse. ON selects a sequence of pulses.
Context Dependencies

With either state (OFF or ON) the output commences at the time and date
defined by :PULSe:STARt:DATE and :PULSe:STARt:TIME commands.

59551A

:PULSe:CONTinuous:STATe?
Identifies whether the Programmable Pulse output is set to output
a single pulse or a sequence of pulses.

RESPONSE FORMAT

0 or 1

This query identifies whether the Programmable Pulse output is set to output
a single pulse or a sequence of pulses.
Response

•

A value of 0 indicates the Receiver is set to output one pulse.

•

A value of 1 indicates the Receiver is set to output a sequence of pulses.

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Programmable Pulse Output (59551A Only)

59551A

:PULSe:REFerence:EDGE . . .

:SYSTem:PRESet

Selects the polarity of the Programmable Pulse on-time edge.

RISing
NON-VOLATILE

This command selects the polarity of the Programmable Pulse on-time edge.
Expanded Syntax
:PULSe:REFerence:EDGE RISing or FALLing
Parameter

The RISing parameter sets the Programmable Pulse rising edge as the on-time
edge.
The FALLing parameter sets the Programmable Pulse falling edge as the
on-time edge.

59551A

:PULSe:REFerence:EDGE?

RESPONSE FORMAT

Returns the polarity of the Programmable Pulse on-time edge.

XYZ

This query returns the polarity of the Programmable Pulse on-time edge.
Response

RIS indicates that the Programmable Pulse on-time edge is the rising edge.
FALL indicates that the Programmable Pulse on-time edge is the falling edge.

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Programmable Pulse Output (59551A Only)

59551A

:PULSe:STARt:DATE . . .
Identifies the date when the individual pulse (or first pulse of the
pulse sequence) is generated at the Programmable Pulse output.

:SYSTem:PRESet

1994, 1, 1
NON-VOLATILE

This command identifies the date when the individual pulse (or first pulse of
the pulse sequence) is generated at the Programmable Pulse output.
Expanded Syntax
:PULSe:STARt:DATE ,,
Parameter

•

The  range is 1994 to 3000.

•

The  range is 1 to 12.

•

The  range is 1 to 31.

Context Dependencies

If you select a date and time which occurs prior to the current time or prior to
the completion of powerup and first GPS lock, the Receiver will not successfully
find a start—and therefore will produce no pulses.
If the Receiver has been set up to use a time zone offset to produce local date
and time, the parameters provided should also be expressed as local date and
time.

59551A

:PULSe:STARt:DATE?
Returns the date when the individual pulse (or first pulse of the
pulse sequence) is generated at the Programmable Pulse output.

RESPONSE FORMAT

± dd, ± dd, ± dd

This query returns the date when the individual pulse (or first pulse of the
pulse sequence) is generated at the Programmable Pulse output. This query
returns year, month, and day.
Response

Three fields are separated by commas: ,,.
•

The  range is 1994 to 3000.

•

The  range is 1 to 12.

•

The  range is 1 to 31.

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59551A

:PULSe:STARt:TIME . . .

:SYSTem:PRESet

Identifies the time when the individual pulse (or first pulse of the
pulse sequence) is generated at the Programmable Pulse output.

0,0,0
NON-VOLATILE

This command identifies the time when the individual pulse (or first pulse of
the pulse sequence) is generated at the Programmable Pulse output.
Expanded Syntax
:PULSe:STARt:TIME ,,
Parameter

Three fields are separated by commas: ,, .
•

The  range is 0 to 23.

•

The  range is 0 to 59.

•

The  range is 0 to 59.

Context Dependencies

If you select a date and time which occurs prior to the current time or prior to
the completion of powerup and first GPS lock, the Receiver will not successfully
find a start—and therefore will produce no pulses.
If the Receiver has been set up to use a time zone offset to produce local date
and time, the parameters provided should also be expressed as local date and
time.

59551A

:PULSe:STARt:TIME?

RESPONSE FORMAT

Returns the time when the individual pulse (or first pulse of the
pulse sequence) is generated at the Programmable Pulse output.

± dd, ± dd, ± dd

This query returns the time when the individual pulse (or first pulse of the
pulse sequence) is generated at the Programmable Pulse output.
Response

Three fields are separated by commas: , , .
•

The  range is 0 to 23.

•

The  range is 0 to 59.

•

The  range is 0 to 59.

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Event Time Stamping (59551A Only)

Event Time Stamping (59551A Only)
The time stamping feature allows you to use the Receiver with equipment such
as a fault analyzer or a surge detector that produces a TTL edge when some
important event happens in the base station. The Receiver has three time
tagging inputs (Time Tag 1, Time Tag 2, Time Tag 3) which record the time
of occurrence of TTL edge(s).
The following commands are provided to allow you to tag and record events
such as power surges and power outages.
" Defining the Time-stamped Edge
:SENSe:TSTamp:EDGE ...
:SENSe:TSTamp:EDGE?

" Clearing Time Stamp Memory
:SENSe:DATA:CLEar
:SENSe:DATA:CLEar ...

" Reading Time Stamps
:SENSe:DATA? ...
:FORMat:DATA ...
:FORMat:DATA?
:SENSe:DATA:POINts?
:SENSe:DATA:POINts? ...
:SENSe:DATA:TSTamp? ...

" Processing Memory Overflow
:SENSe:DATA:MEMory:OVERflow:COUNt?
:SENSe:DATA:MEMory:OVERflow:COUNt? ...
:SENSe:DATA:MEMory:SAVE ...
:SENSe:DATA:MEMory:SAVE?

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Event Time Stamping (59551A Only)

Defining the Time-stamped Edge _________________________
59551A

:SENSe:TSTamp:EDGE . . .

:SYSTem:PRESet

Selects the polarity of the edges the Receiver will time stamp.

RISing
NON-VOLATILE

This command selects the polarity of the edges the Receiver will time stamp.
Expanded Syntax
:SENSe:TSTamp1:EDGE RISing or FALLing
:SENSe:TSTamp2:EDGE RISing or FALLing
:SENSe:TSTamp3:EDGE RISing or FALLing
Parameter

•

The RISing parameter sets the time-stamped edge as the rising edge.

•

The FALLing parameter sets the time-stamped edge as the falling edge.

59551A

:SENSe:TSTamp:EDGE?

RESPONSE FORMAT

Returns the polarity of the edges the Receiver will time stamp.

XYZ

This query returns the polarity of the edges the Receiver will time stamp.
Response

RIS indicates that the time-stamped edge is the rising edge.
FALL indicates that the time-stamped edge is the falling edge.

59551A

c

a b

:SENSe:DATA:CLEar
Clears the data in the measurement buffer for all Time Tag inputs.

EVENT

This command clears the data in the measurement buffer and clears the
overflow counts for all Time Tag inputs.
Context Dependencies

:SYSTem:PRESet clears the time stamp measurement buffers and overflow
counts.

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Event Time Stamping (59551A Only)

Clearing Time Stamp Memory ____________________________
59551A

:SENSe:DATA:CLEar . . .
Clears the data in the time stamp measurement buffer for the userspecified Time Tag input.

EVENT

This command clears the data in the time stamp measurement buffer for the
user-specified Time Tag input. Use "TSTamp 1" or "TSTamp 2" or "TSTamp 3"
to select one input.
Expanded Syntax
:SENSe:DATA:CLEar "TSTamp 1" or "TSTamp 2" or "TSTamp 3"
Parameter

"TSTamp 1" clears the data in Time Tag 1 input buffer.
"TSTamp 2" clears the data in Time Tag 2 input buffer.
"TSTamp 3" clears the data in Time Tag 3 input buffer.
Context Dependencies

:SYSTem:PRESet clears the time stamp measurement buffers.

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Reading Time Stamps ____________________________________
59551A

:SENSe:DATA? . . .

RESPONSE FORMAT

Outputs data from the one specified time stamp measurement
buffer.

FORMAT = ASCii

± dd, ...
FORMAT = INTeger

BINARY Data

This query outputs data from the one specified time stamp measurement buffer
(or Time Tag input). This query does not clear the buffer. Each time stamp
provides the year, month, day, hours, minutes, seconds, milliseconds,
microseconds, nanoseconds, and TFOM (Time Figure of Merit).
Expanded Syntax
:SENSe:DATA? "TSTamp 1" or "TSTamp 2" or "TSTamp 3"
Response

If the format is ASCii (the default format), the response is a sequence of
comma-separated integers.
If the format is INTeger, the response is BINARY Data (see Table B-3, in
Appendix B, “Command Syntax and Style,” in this guide for details).
To determine which format is selected, use query :FORmat:DATA?.
Parameter

Use "TSTamp 1" or "TSTamp 2" or "TSTamp 3" to select one input at a time:
•

"TSTamp 1" outputs the data from Time Tag 1 input buffer.

•

"TSTamp 2" outputs the data from Time Tag 2 input buffer.

•

"TSTamp 3" outputs the data from Time Tag 3 input buffer.

Context Dependencies

:SYSTem:PRESet clears the time stamp measurement buffers and overflow
counts.
Time stamps are not collected until after the Receiver has completed its
powerup, and has reached initial lock to GPS.
Time stamps are not collected while the user is reading/clearing or otherwise
accessing the time stamp buffers.

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Event Time Stamping (59551A Only)

Reading Time Stamps __________________________ (continued)
59551A

:FORMat:DATA . . .

:SYSTem:PRESet

Selects output format for the time stamps.

ASCii
NON-VOLATILE

This command selects the output format for the time stamps.
Expanded Syntax
:FORMat:DATA ASCii or INTeger
Parameter

If the format is ASCii (the default format), the response is a sequence of
comma-separated integers.
If the format is INTeger, the response to the :SENSe:DATA? query is BINARY
Data (see Table B-3, in Appendix B, “Command Syntax and Style,” in this
guide for details).
When ASCii formatting is selected the output stream data is buffered. In
general, INT mode will provide faster output than ASC, but will require special
data-handling routines to interpret the BINARY Data.

59551A

:FORMat:DATA?
Returns the output format for time stamp data.

RESPONSE FORMAT

XYZ

This query returns the output format for time stamp data.
Response

ASC or INT is returned.

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Reading Time Stamps __________________________ (continued)
59551A

:SENSe:DATA:POINts?

RESPONSE FORMAT

Returns the number of time stamps in each of the three Time Tag
inputs.

± dd, ...

This query returns the number of time stamps in each of the three Time Tag
inputs.
Response

Returns three comma-separated integers corresponding to the number of time
stamps recorded for inputs 1, 2, and 3.
The numeric range for each integer is 0 to 256.
Context Dependencies

:SYSTem:PRESet clears the time stamp measurement buffers and overflow
counts.
Time stamps are not collected until after the Receiver has completed its
powerup and has reached initial GPS lock.

59551A

:SENSe:DATA:POINts? . . .

RESPONSE FORMAT

Returns the number of time stamps recorded for the one specified
Time Tag input.

± dd

This query returns the number of time stamps recorded for the one specified
Time Tag input. Use "TSTamp 1", "TSTamp 2", or "TSTamp 3" to select one
input.
Expanded Syntax
:SENSe:DATA:POINts? "TSTamp 1" or "TSTamp 2" or "TSTamp 3"
Response

Returns an integer corresponding to the number of time stamps recorded for
the specified input.
•

Numeric range is 0 to 256.

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Event Time Stamping (59551A Only)

Reading Time Stamps __________________________ (continued)
Parameter

"TSTamp 1"queries for the number of points in Time Tag 1 input buffer.
"TSTamp 2" queries for the number of points in Time Tag 2 input buffer.
"TSTamp 3" queries for the number of points in Time Tag 3 input buffer.
Context Dependencies

:SYSTem:PRESet clears the time stamp measurement buffers and overflow
counts.
Time stamps are not collected until after the Receiver has completed its
powerup and has reached initial GPS lock.

59551A

:SENSe:DATA:TSTamp? . . .

RESPONSE FORMAT

Returns a single time stamp.

± dd, ...

This query returns a single time stamp. Use "TSTamp 1" or "TSTamp 2" or
"TSTamp 3" to select an input channel. Use  to select a
single time stamp recorded on that input.
Expanded Syntax
:SENSe:DATA:TSTamp? "TSTamp 1" or "TSTamp 2" or "TSTamp 3",

Response

The query response represents the single time stamp requested.
The query response is a sequence of ten comma-separated integers constituting
a single time stamp. The time stamp provides the year, month, day, hours,
minutes, seconds, milliseconds, microseconds, nanoseconds, and TFOM (Time
Figure of Merit).
For example,
:SENSe:DATA:TSTamp? "TSTamp 2", 37

Selects the 37th time stamp recorded on Time Tag Input 2.

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Reading Time Stamps __________________________ (continued)
Parameter

 parameter:
•

"TSTamp 1" to select Time Tag 1 input buffer.

•

"TSTamp 2" to select Time Tag 2 input buffer.

•

"TSTamp 3" to select Time Tag 3 input buffer.

 parameter range is 1 to 256.
Context Dependencies

:SYSTem:PRESet clears the time stamp measurement buffers and overflow
counts.
Time stamps are not collected until after the Receiver has completed its
powerup and has reached initial GPS lock.

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Event Time Stamping (59551A Only)

Processing Memory Overflows ____________________________
59551A

:SENSe:DATA:MEMory:OVERflow:COUNt?
Returns an overflow count for each of the three Time Tag inputs.

RESPONSE FORMAT

± d.dEe, ...

This query returns an overflow count for each of the three Time Tag inputs.
An “overflow count” occurs after 256 time stamps have been recorded. When
any additional events are detected at the input, the overflow count increments.
If memory management protocol has been set to “FIRST,” the first 256 time
stamps are recorded. The overflow count indicates the number of time stamps
which followed the last recorded stamp, and which were discarded.
If memory management protocol has been set to “LAST,” the most recent
256 time stamps are recorded. The overflow count indicates the number of
stamps which were collected prior to the first recorded stamp, and which were
overwritten.
Response

Returns three comma-separated floating-point numbers corresponding to the
overflow count of each of the three inputs: 1, 2, 3.
Context Dependencies

:SYSTem:PRESet clears the time stamp measurement buffers and overflow
counts.
Time stamps are not collected until after the Receiver has completed its
powerup and has reached initial GPS lock.

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Event Time Stamping (59551A Only)

Processing Memory Overflows __________________ (continued)
59551A

:SENSe:DATA:MEMory:OVERflow:COUNt? . . .

RESPONSE FORMAT

Returns an overflow count for the selected Time Tag input.

± d.dEe

This query returns an overflow count for the selected Time Tag input.
Use "TSTamp 1", "TSTamp 2", or "TSTamp 3" to select or query one input at a
time.
Expanded Syntax
:SENSe:DATA:MEMory:OVERflow:COUNt? "TSTamp 1" or "TSTamp 2" or "TSTamp 3"
Response

Returns one floating-point number corresponding to the overflow count of the
selected Time Tag input.
Context Dependencies

:SYSTem:PRESet clears the time stamp measurement buffers and overflow
counts.
Time stamps are not collected until after the Receiver has completed its
powerup and has reached initial GPS lock.

59551A

:SENSe:DATA:MEMory:SAVE . . .

:SYSTem:PRESet

Sets the Receiver’s memory management protocol.

FIRSt
NON-VOLATILE

This command sets the Receiver’s memory management protocol.
Expanded Syntax
:SENSe:DATA:MEMory:SAVE FIRSt or LAST
Parameter

FIRSt retains time stamps for the first 256 events detected.
LAST retains time stamps of the last (most recent) 256 events detected.
Context Dependencies

:SYSTem:PRESet sets memory management protocol to retain time stamps for
FIRSt 256 events.

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Processing Memory Overflows __________________ (continued)
59551A

:SENSe:DATA:MEMory:SAVE?
Returns the state of the memory management protocol.

RESPONSE FORMAT

XYZ

This query returns the state of the memory management protocol.
Response

FIRSt indicates that the memory retains time stamps for the first 256 events
detected.
LAST indicates that the memory retains time stamps for the last (most recent)
256 events detected.

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Serial Interface Communication

Serial Interface Communication
The 59551A and 58503B GPS Receivers provide a set of commands that allow
you to configure the serial interface port(s) for instrument communications. A
set of special commands is provided for the 59551A Receiver since it has two
different serial ports (PORT 1, PORT 2).
Both Receivers have the rear-panel RS-232C serial interface port (PORT 1).
The 59551A has an additional front-panel RS-232C serial interface port
(PORT 2).
The following commands are provided to allow you to configure the ports.
! Configuring I/O Port 1  = SERial1 or SERial

Configuring I/O Port 2  = SERial2 (59551A Only)
:SYSTem:COMMunicate?
:SYSTem:COMMunicate::BAUD ...
:SYSTem:COMMunicate::BAUD?
:SYSTem:COMMunicate:SERial1:BITS ...
:SYSTem:COMMunicate::BITS?
:SYSTem:COMMunicate::FDUPlex ...
:SYSTem:COMMunicate::FDUPlex?
:SYSTem:COMMunicate::PACE ...
:SYSTem:COMMunicate::PACE?
:SYSTem:COMMunicate::PARity ...
:SYSTem:COMMunicate::PARity?
:SYSTem:COMMunicate:SERial1:SBITs ...
:SYSTem:COMMunicate::SBITs?

(59551A)

(59551A)

! Recovering the Last Query Response
:DIAGnostic:QUERy:RESPonse?

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Serial Interface Communication

Configuring I/O Ports _____________________________________

:SYSTem:COMMunicate?

RESPONSE FORMAT

Identifies which serial port is being used.

XYZ

This query identifies which serial port is being used. Use this query when the
Receiver is installed out of sight or at a remote location. The distinction
between SERIAL1 and SERIAL2 is required in communication commands for
setting parameters such as baud and parity.
Response

SER1 or SER2 is returned.

:SYSTem:COMMunicate::BAUD . . .

:SYSTem:PRESet

Sets the baud rate of specified port.

R, F=

Not affected

NON-VOLATILE

This command sets the baud rate of the specified port.
Expanded Syntax
:SYSTem:COMMunicate:SERial1:BAUD 1200 or 2400 or 9600 or 19200
:SYSTem:COMMunicate:SERial2:BAUD 1200 or 2400 or 9600 or 19200
Parameter

The possible baud rate values that can be entered are 1200, 2400, 9600, or
19200.
Context Dependencies

The baud rate value is stored in non-volatile memory. It is unaffected by
powerup and :SYSTem:PRESet.
:SYSTem:COMMunicate::PRESet sets the baud rate to 9600, which is
the factory-default value.

= Must be received via the specified I/O port.

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Configuring I/O Ports ___________________________ (continued)

:SYSTem:COMMunicate::BAUD?

RESPONSE FORMAT

R, F

±dd

Returns the baud rate of specified port.

This query returns the baud rate of specified port.
Expanded Syntax
:SYSTem:COMMunicate:SERial1:BAUD?
:SYSTem:COMMunicate:SERial2:BAUD?

59551A

:SYSTem:COMMunicate:SERial1:BITS . . .
Sets the data bits value of PORT 1.

:SYSTem:PRESet

R

Not affected
NON-VOLATILE

This command sets the data bits of PORT 1.
Expanded Syntax
:SYSTem:COMMunicate:SERial1:BITS 7 or 8
Parameter

The possible data bits values that can be entered are 7 or 8.
Context Dependencies

The data bits value is stored in non-volatile memory. It is unaffected by
powerup and :SYSTem:PRESet.
:SYSTem:COMMunicate:SERial1:PRESet sets the data bits to 8, which is the
factory-default value.

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Serial Interface Communication

Configuring I/O Ports ___________________________ (continued)

:SYSTem:COMMunicate::BITS?
Returns the data bits value of specified port.

RESPONSE FORMAT

R, F

± dd

This query returns the data bits value of the specified port.
Expanded Syntax
:SYSTem:COMMunicate:SERial1:BITS?
:SYSTem:COMMunicate:SERial2:BITS?

:SYSTem:COMMunicate::FDUPlex . . .
Sets the duplex state of specified port.

:SYSTem:PRESet

R, F=

Not affected
NON-VOLATILE

This command sets the duplex state of the specified port. Use this command
when you cannot see on the computer screen the characters you are typing for
your command.
Expanded Syntax
:SYSTem:COMMunicate:SERial1:FDUPlex ON or OFF
:SYSTem:COMMunicate:SERial2:FDUPlex ON or OFF
Parameter

ON enables echoing of the characters you type (i.e., when typing a command,
the ON state allows you to see on the computer screen the characters you type).
OFF disables the echoing of the characters you type.
Context Dependencies

The duplex state is stored in non-volatile memory. It is unaffected by powerup
and :SYSTem:PRESet.
SYSTem:COMMunicate::PRESet sets the duplex state to ON, which is
the factory-default state.

= Must be received via the specified I/O port.

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Configuring I/O Ports ___________________________ (continued)

:SYSTem:COMMunicate::FDUPlex?

RESPONSE FORMAT

Returns the duplex state of the specified port.

R, F

0 or 1

This query returns the duplex state of the specified port.
Expanded Syntax
:SYSTem:COMMunicate:SERial1:FDUPlex?
:SYSTem:COMMunicate:SERial2:FDUPlex?
Response

A value of 0 indicates echo is OFF.
A value of 1 indicates echo is ON.

:SYSTem:COMMunicate::PACE . . .
Sets flow control of the specified port.

:SYSTem:PRESet

R, F=

Not affected
NON-VOLATILE

This command sets flow control of the specified port.
Expanded Syntax
:SYSTem:COMMunicate:SERial1:PACE XON or NONE
:SYSTem:COMMunicate:SERial2:PACE XON or NONE
Parameter

The choices are XON or NONE.
Context Dependencies

The software pacing or flow control state is stored in non-volatile memory. It is
unaffected by powerup and :SYSTem:PRESet.
:SYSTem:COMMunicate::PRESet sets the flow control to NONE, which
is the factory-default state.

= Must be received via the specified I/O port.

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Serial Interface Communication

Configuring I/O Ports ___________________________ (continued)

:SYSTem:COMMunicate::PACE?

RESPONSE FORMAT

Returns flow control state of the specified port.

R, F

XYZ

This query returns the flow control state of specified port.
Expanded Syntax
:SYSTem:COMMunicate:SERial1:PACE?
:SYSTem:COMMunicate:SERial2:PACE?
Response

XON or NONE is returned.

:SYSTem:COMMunicate::PARity . . .
Sets parity of the specified port.

:SYSTem:PRESet

R, F=

Not affected
NON-VOLATILE

This command sets parity of the specified port.
Expanded Syntax
:SYSTem:COMMunicate:SERial1:PARity: EVEN or ODD or NONE
:SYSTem:COMMunicate:SERial2:PARity: EVEN or ODD or NONE or ONE
Parameter

The choices for SERial1 are EVEN, ODD, or NONE.
The choices for SERial2 are EVEN, ODD, NONE, or ONE.
Context Dependencies

The parity state is stored in non-volatile memory. It is unaffected by powerup
and :SYSTem:PRESet.
:SYSTem:COMMunicate::PRESet sets the parity to NONE, which is the
factory-default state.
If parity is enabled, the Receiver sends/receives 7 data bits plus 1 parity bit.
If parity is disabled, the Receiver sends/receives 8 data bits.

= Must be received via the specified I/O port.

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Configuring I/O Ports ___________________________ (continued)

:SYSTem:COMMunicate::PARity?

RESPONSE FORMAT

Returns parity setting of the specified port.

R, F

XYZ

This query returns the parity setting of the specified port.
Expanded Syntax
:SYSTem:COMMunicate:SERial1:PARity?
:SYSTem:COMMunicate:SERial2:PARity?
Response

EVEN, ODD, NONE, or ONE is returned.

59551A

:SYSTem:COMMunicate:SERial1:SBITs . . .
Sets the stop bits value of PORT 1.

:SYSTem:PRESet

R

Not affected
NON-VOLATILE

This command sets the stop bits value of PORT 1.
Expanded Syntax
:SYSTem:COMMunicate:SERial1:SBITs 1 or 2
Parameter

The possible stop bits values that can be entered are 1 or 2.
Context Dependencies

The stop bits value is stored in non-volatile memory. It is unaffected by
powerup and :SYSTem:PRESet.
:SYSTem:COMMunicate:SERial1:PRESet sets the stop bits value to 1, which
is the factory-default value.

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Configuring I/O Ports ___________________________ (continued)

:SYSTem:COMMunicate::SBITs?

RESPONSE FORMAT

Returns the stop bits value of the specified port.

R, F

± dd

This query returns the stop bits value of specified port.
Expanded Syntax
:SYSTem:COMMunicate:SERial1:SBITs?
:SYSTem:COMMunicate:SERial2:SBITs?

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Recovering the Last Query Response _____________________

:DIAGnostic:QUERy:RESPonse?

RESPONSE FORMAT

Returns the last response item issued through the Receiver's
serial interface for use in an error recovery process.

Format depends on the last
issued query.

This query returns the last response item issued through the Receiver’s serial
interface for use in an error recovery process.
In the case of a serial interface data transmission error, this query can be used
to get the last response item which may otherwise be unavailable because of
the side effects of the original command. For example, the :SYST:ERRor? query
removes the oldest entry from the error queue, so to see the entry again
following a data transmission error, use :DIAG:QUER:RESP? instead of
repeating the original command.
Response

The format depends on the last issued query.

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Receiver Initialization

Receiver Initialization
The following commands are provided to allow you to initialize or preset the
serial interface port(s) and the Receiver to their factory shipment values.

:SYSTem:COMMunicate:SERial1:PRESet
:SYSTem:COMMunicate:SERial2:PRESet (59551A Only)
:SYSTem:PRESet

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:SYSTem:COMMunicate::PRESet
Sets the specified port configuration to its factory-default
values.

EVENT

This command is an event that sets specified port parameters to their
factory-default values.
Expanded Syntax
:SYSTem:COMMunicate:SERial1:PRESet
:SYSTem:COMMunicate:SERial2:PRESet

Factory-Default Settings for PORT 1 of the 59551A
Parameter
Software Pacing
Baud Rate
Parity
Data Bits
Stop Bits
Full Duplex

Default
NONE
9600
NONE
8
1
ON

Possible Choices
XON or NONE
1200, 2400, 9600, or 19200
EVEN, ODD, or NONE
7 or 8
1 or 2
ON or OFF

Factory-Default Settings for PORT 1 of the 58503B and PORT 2 of the
59551A
Parameter
Software Pacing
Baud Rate
Parity
Data Bits

Default
NONE
9600
NONE
8

Possible Choices
XON or NONE
1200, 2400, 9600, or 19200
EVEN, ODD, NONE, or ONE
Fixed at 7 when parity is even or odd.

Stop Bits
Full Duplex

1
ON

Fixed at 8 when parity is none.
Fixed (no choices available)
ON or OFF

Context Dependencies

The SERial1 preset command only is valid if transmitted on the rear-panel
(PORT 1).
:SYSTem:PRESet
Restores the Receiver parameters settings to their
factory-default values.

EVENT

This command is an event that restores the Receiver parameters settings to
their factory shipment or factory-default values (see the following Table 5-2).
NOTE

Issuing this command will result in disruption of all of the following: GPS
satellite tracking, reference oscillator frequency, 1 PPS output timing, and
Receiver status information.

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Receiver Initialization

Table 5-2. System Preset (Factory Default) Parameter Settings
Summary
Commands

:SYSTem:PRESet

*ESE ...

0 (NV*) — See footnotes on the
bottom of the next page

*SRE ...

136 (NV)

:DIAGnostic:LOG:CLEar

Log is cleared.

:DIAGnostic:LOG:COUNt?

2

:DIAGnostic:QUERy:RESPonse?

cleared.

:FORMat:DATA ...

ASCII (NV)

:GPS:POSition ...

N,0,0,0,E,0,0,0,0 (NV)
LAST is also set to this position.
(NV)

:GPS:POSition:HOLD:LAST?

N,0,0,0,E,0,0,0,0 (NV)

:GPS:POSition:HOLD:STATe?

0 (NV)

:GPS:POSition:SURVey:STATe ...

ONCE

:GPS:POSition:SURVey:STATe:POWerup ...

ON (NV)

:GPS:REFerence:ADELay ...

0.0 (NV)

:GPS:SATellite:TRACking:EMANgle ...

10 (NV)

:GPS:SATellite:TRACking:IGNore:STATe? ...

0 for every PRN.

:GPS:SATellite:TRACking:IGNore ...

No satellites ignored (NV)

:GPS:SATellite:TRACking:INCLude ...

All satellites included (NV)

:GPS:SATellite:TRACking:INCLude:STATe? ...

1 for every PRN.

:PTIMe:TZONe ...

0,0 (NV)

:PULSe:CONTinuous:PERiod ...

1 (NV)

:PULSe:CONTinuous:STATe ...

OFF (NV)

:PULSe:STARt:DATE ...

1994,1,1 (NV)

:PULSe:STARt:TIME ...

0,0,0 (NV)

:SENSe:DATA?

Data is cleared.

:SENSe:DATA:MEMory:OVERflow:COUNt?

All counts are cleared (V**).

:SENSe:DATA:MEMory:SAVE ...

FIRSt (NV)

:SENSe:DATA:POINts?

All responses become 0 (zero).
(V)

:SENSe:DATA:TSTamp? ...

All timestamps cleared.

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Table 5-2. System Preset (Factory Default) Parameter Settings
Summary (Continued)
Commands

:SYSTem:PRESet

:STATus:OPERation:ENABle ...

36 (NV)

:STATus:OPERation:HARDware:ENABle ...

8191 (NV)

:STATus:OPERation:HARDware:NTRansition ...

0 (NV)

:STATus:OPERation:HARDware:PTRansition ...

5119 (NV)

:STATus:OPERation:HOLDover:ENABle ...

8 (NV)

:STATus:OPERation:HOLDover:NTRansition ...

0 (NV)

:STATus:OPERation:HOLDover:PTRansition ...

15 (NV)

:STATus:OPERation:NTRansition ...

0 (NV)

:STATus:OPERation:POWerup:ENABle ...

7 (NV)

:STATus:OPERation:POWerup:NTRansition ...

0 (NV)

:STATus:OPERation:POWerup:PTRansition ...

7 (NV)

:STATus:OPERation:PTRansition ...

127 (NV)

:STATus:QUEStionable:CONDition:USER ...

Cleared (NV)

:STATus:QUEStionable:ENABle ...

3 (NV)

:STATus:QUEStionable:NTRansition ...

0 (NV)

:STATus:QUEStionable:PTRansition ...

2 (NV)

:SYNChronization:HOLDover:DURation?

0,0 (Even if there was a prior
holdover, its duration will be lost.)

:SYNChronization:HOLDover:DURation:THReshold ...

86400 (that is, 1 day), (NV)

:SYNChronization:STATe?

POWerup

:SYSTem:ERRor?

Error queue is cleared.

:SYSTem:LANGuage ...

"PRIMARY"

* NV stands for non-volatile memory.
** V stands for volatile memory.

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Receiver Identification/Upgrade

Receiver Identification/Upgrade
The commands provided in this section allow you to query the identification of
the Receiver, and to perform firmware upgrades in the field after you obtain a
new firmware disk.
! Reading Product Identification
*IDN?

! Installing Firmware via I/O PORT 1
*CLS
:DIAGnostic:DOWNload ...
:DIAGnostic:ERASe
:DIAGnostic:ERASe?
:SYSTem:ERRor?
:SYSTem:LANGuage ...
:SYSTem:LANGuage?

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Reading Product Identification ___________________________

*IDN?

RESPONSE FORMAT

Returns the Receiver identification.

ASCII Data

This query returns the Receiver identification.
Response

•

A sequence of ASCII-encoded bytes:
HEWLETT-PACKARD, 59551A, XXXXYZZZZZ, WWWW – V
where 59551A is the product model number, XXXXYZZZZZ is the product
serial number, and WWWW is the product’s firmware revision date code,
and V is the hardware revision letter.
In the product serial number (XXXXYZZZZZ):

•

–

XXXX is a four-digit prefix that identifies a series of instruments.

–

Y identifies the country in which the instrument was manufactured
(e.g., the “A” in 3426A000123 stands for America).

–

ZZZZZ is a five-digit suffix that identifies a particular instrument
within a series.

For example,
HEWLETT-PACKARD, 59551A,3426A00123,3422 – A
This query should be the last query in a terminated program message;
otherwise, error -440 is generated.

Context Dependencies

Preparatory to installation of new product firmware, the instrument is
switched to the “INSTALL” language, available only on PORT 1.
The “INSTALL” language includes an *IDN? query which returns the revision
identification for the installation firmware. The response format is the same as
described above for the instrument’s “PRIMARY” language, but the
identification code may be different.

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Installing Firmware via I/O PORT 1 ______________________
The commands in this section represent the command set of the “INSTALL”
language. The “INSTALL” language is part of a highly-specialized set of
features used to erase the Receiver’s firmware, and to install a new firmware
revision. It should be selected only when firmware installation is required.
The “INSTALL” language offers the limited number of commands and queries
which are documented in this section. This set is designed to provide the
Receiver status and control capability required during firmware upgrade.
The SatStat program provides a Service menu which automates firmware
installation.

NOTE

*CLS
Clears errors.

R
EVENT

This command clears errors.

R

:DIAGnostic:DOWNload . . .
Sends down a MotorolaS-record.

EVENT

This command sends down a Motorola S-record.
Expanded Syntax
:DIAGnostic:DOWNload 

!

R

:DIAGnostic:ERASe
Erases the flash EEPROM.

EVENT

This command erases the flash EEPROM. It should ONLY be sent to the
Receiver as a preparatory step during firmware upgrade. Erasing flash
EEPROM will disable the instrument until flash EEPROM is reloaded with
factory-supplied instrument firmware.

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Installing Firmware via I/O Port 1 ______________ (continued)

:DIAGnostic:ERASe?

RESPONSE FORMAT

Verifies flash EEPROM has been erased.

R

0 or 1

This query verifies the flash EEPROM has been erased.
Response

A value of 1 indicates that flash EEPROM has been erased.
This condition normally occurs when the instrument software in flash
EEPROM is erased in preparation for installation of a more recent software
revision. That is, after command :DIAG:ERASe has been issued and erase is
complete, the :DIAG:ERASe? query response is “1”.

:SYSTem:ERRor?

RESPONSE FORMAT

Returns the oldest error in the Error Queue and removes
that error from the queue (first in, first out).

R

± dd, “XYZ”

This query returns the oldest error in the Error Queue and removes that error
from the queue (first in, first out).
See Appendix A, “Error Messages,” in this guide for detailed error information.
Response

The error response format is: ,"", where
•

The  is an integer transferred as ASCII bytes in 
format (integer). The range is -32768 to 32767.

•

Negative error numbers are defined by the SCPI standard.

•

Positive error numbers are defined specifically for this Receiver.

•

An error number value of zero indicates that the Error Queue is empty.

•

The maximum length of the  is 255 characters.

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Receiver Identification/Upgrade

Installing Firmware via I/O Port 1 ______________ (continued)
Context Dependencies

:SYSTem:PRESet clears the Error Queue.
The queue is cleared (emptied) on *CLS, power-on, or upon reading the last
error from the queue.
If the Error Queue overflows, the last error in the queue is replaced with the
error -350, "Queue overflow". Any time the queue overflows, the least recent
errors remain in the queue and the most recent error is discarded.
The maximum length of the Error Queue is 30.

:SYSTem:LANGuage . . .
Switches the operation mode (primary or install) of the
Receiver.

:SYSTem:PRESet

“PRIMARY”

NON-VOLATILE

This command switches the operation mode (primary or install) of the
Receiver.
Expanded Syntax

:SYSTem:LANGuage "INSTALL" or "PRIMARY".
Parameter

The “INSTALL” language is part of a highly-specialized set of features used to
erase the Receiver’s firmware, and to install a new firmware revision. It should
be selected only when firmware installation is required.
The “INSTALL” language offers the limited number of commands and queries
which are documented in this section. This set is designed to provide the
Receiver status and control capability required during firmware upgrade.
NOTE

The SatStat program provides a Service menu which automates firmware
installation.
The “PRIMARY” language provides the capabilities required for normal
Receiver operation. If the “INSTALL” language has been selected as part of the
firmware upgrade, the “PRIMARY” language should be selected after the
upgrade to restore normal operation.

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Chapter 5 Command Reference
Receiver Identification/Upgrade

Installing Firmware via I/O Port 1 ______________ (continued)

:SYSTem:LANGuage?

RESPONSE FORMAT

Identifies the operation mode (primary or install) of the
Receiver.

R

“XYZ”

This query identifies the operation mode (primary or install) of the Receiver.
Response

“INSTALL” or “PRIMARY” is returned.

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A

Error Messages

Appendix A Error Messages
Introduction

Introduction
This appendix explains how to read any errors from the Receiver,
discusses the error queue, types of errors and general error behavior,
and provides a table of all of the Receiver’s errors and their probable
causes.

Reading an Error
Executing the :SYSTEM:ERROR? command reads the oldest error from
the error queue and erases that error from the queue. The :SYST:ERR?
response has the form:
, 
An example response is:
-113,"Undefined header"
Positive error numbers are specific to the Receiver. Negative error
numbers are command language related and are discussed later in this
appendix.
All errors set a corresponding bit in the Standard Event Status
Register (see Figure 5-1 on page 5-49).

A-2

Operating and Programming Guide

Appendix A Error Messages
Error Queue

Error Queue
As errors are detected, they are placed in an error queue. This queue is
first in, first out. That is, if there has been more than one error, the
first one in the queue is read out with :SYST:ERR?. Subsequent
responses continue until the queue is empty.
If the error queue overflows, the last error in the queue is replaced
with error -350, "Queue overflow". Any time the queue overflows, the
least recent errors remain in the queue, and the most recent error is
discarded. The length of the Receiver’s error queue is 30 (29 positions
for the error messages, and 1 position for the “Queue overflow” error).
Reading an error from the head of the queue removes that error from
the queue, and opens a position at the tail of the queue for a new error,
if one is subsequently detected.
When all errors have been read from the queue, further error queries
return +0, "No error".
The error queue is cleared when any of the following occur:
•

Upon power-on.

•

Upon receipt of a *CLS command.

•

Upon reading the last item from the queue.

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Appendix A Error Messages
Error Types

Error Types
Error numbers are categorized by type as shown in Table A-1. Each
error is listed in Table A-2.
Table A-1. Error Types
Error Number

Error Type

+0

No Error

−100 to −199

Syntactic Errors

−200 to −299

Semantic Errors

−300 to −350

Hardware/Firmware Errors

−400 to −499

Query Errors

The first error described in each class (for example, −100, −200, −300,
−400) is a “generic” error.

No Error
The :SYST:ERR? response +0, "No error" indicates that the Receiver
has no errors. The error queue is empty when every error in the queue
has been read (:SYST:ERR? query) or the queue was cleared by poweron or *CLS.

Syntactic Error
An  in the range [−100 to −199] indicates that an IEEE
488.2 syntax error has been detected by the Receiver’s parser.
The occurrence of any error in this class causes the syntactic error bit
(bit 5) in the Event Status Register to be set. One of the following
events has occurred:
•

An IEEE 488.2 syntax error has been detected by the parser.
That is, a controller-to-Receiver message was received that is in
violation of the IEEE 488.2 Standard. Possible violations include a
data element that violates the Receiver listening formats or whose
type is unacceptable to the Receiver.

•

An unrecognized header was received. Unrecognized headers
include incorrect Receiver-specific headers and incorrect or
unimplemented IEEE 488.2 Common Commands.

Events that generate syntactic errors do not generate semantic errors,
hardware/firmware errors, or query errors.

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Operating and Programming Guide

Appendix A Error Messages
Error Types

Semantic Error
An  in the range [−200 to −299] indicates that an error
has been detected by the Receiver’s execution control block.
The occurrence of any error in this class causes the semantic error bit
(bit 4) in the Event Status Register to be set. One of the following
events has occurred:
•

A  element following a header was evaluated
by the Receiver as outside of its legal input range or is otherwise
inconsistent with the Receiver’s capabilities.

•

A valid program message could not be properly executed due to
some Receiver condition.

Semantic errors are reported by the Receiver after rounding and
expression evaluation operations have been taken place. Rounding a
numeric data element, for example, is not reported as a semantic error.
Events that generate semantic errors do not generate syntactic errors,
hardware/firmware errors, or query errors.

Hardware/Firmware Error
An  in the range [−300 to −399] or [+1 to +32767]
indicates that the Receiver has detected an error that is not a syntactic
error, a query error, or a semantic error; some Receiver operations did
not properly complete, possibly due to an abnormal hardware or
firmware condition. These codes are also used for self-test response
errors. The occurrence of any error in this class causes the
hardware/firmware error bit (bit 3) in the Event Status Register to
be set.

Query Error
An  in the range [−400 to −499] indicates that the
output queue control of the Receiver has detected a problem with the
message exchange protocol. The occurrence of any error in this class
should cause the query error bit (bit 2) in the Event Status Register to
be set. One of the following is true:
•

An attempt is being made to read data from the output queue when
no output is either present or pending.

•

Data in the output queue has been lost.

Operating and Programming Guide

A-5

Appendix A Error Messages
General Error Behavior

General Error Behavior
For Commands (i.e., non-query; doesn’t provide a response):
•

For any command that has numeric parameters, if the value is out
of range (beyond either the min or max allowed settings), the value
will be clipped to the appropriate limit and error −222 will be
generated (data out-of-range error) as an indication that the value
wasn’t set to the requested value.
There are some commands having numeric parameters where the
clipping behavior described above doesn’t make sense. These
include the satellite include and ignore commands, and the status
system mask commands. For these commands, an out-of-bounds
value is ignored and error −222 is generated. Also, a single
out-of-bounds value may cause the entire command to be ignored.
For example, GPS:SAT:TRAC:INCL 3,87,5 will be entirely ignored
because 87 is out-of-range (i.e., 3 and 5 do not become included even
though they are in-range).

•

Commands with multiple numeric parameters can produce
multiple errors. For example, if the initial date command is sent as
GPS:INIT:TIME 25,66,−7, the actual programmed value will be
23:59:00 (23 is max hour, 59 is max minute, 0 is min second) and
three out-of-range errors will be generated. As always, only a single
prompt will be returned, but in this case three errors will be in the
error queue (de-queued via SYST:ERR? or *CLS).

•

Numeric parameters between in-range values are rounded to the
closest value. For example, sending GPS:REF:ADEL 1.7 ns will set
the antenna delay to 2 ns.

For Queries (response-generating commands)
•

If the query produces an error, there will not be a response (other
than the prompt that always occurs).

•

If the query includes a numeric parameter, and that parameter is
out of range, error −222 will be generated and there won’t be a
response (this is consistent with the prior bullet). An example of
this would be DIAG:LOG:READ? 25 when there are fewer than
25 messages in the log. Note that for this specific example, to get
the most recent log entry, simply use DIAG:LOG:READ?.

•

Another way you can view this: if you get a query response you can
know that it is responding precisely to the question asked by the
query.

A-6

Operating and Programming Guide

Appendix A Error Messages
List of Errors

List of Errors
Table A-2 lists and describes the error messages
Table A-2. Error Messages
Number

Error String

Cause

+0

No error

The error queue is empty. Every error in the queue has been read (SYSTem:ERRor?
query) or the queue was cleared by power-on or *CLS.

-100

Command error

This is the generic syntax error used if the Receiver cannot detect more specific
errors.

-101

Invalid character

A syntactic element contains a character that is invalid for that type.

-102

Syntax error

An unrecognized command or data type was encountered.

-103

Invalid separator

The parser was expecting a separator and encountered an illegal character.

-104

Data type error

The parser recognized a data element different than one allowed. For example,
numeric or string data was expected, but block data was received.

-108

Parameter not allowed

More parameters were received than expected for the header.

-109

Missing parameter

Fewer parameters were received than required for the header.

-112

Program mnemonic too long

The header or character data element contains more than twelve characters.

-113

Undefined header

The header is undefined. For example, the command ":HELLO".

-120

Numeric data error

This error, as well as errors -121 through -129, is generated when parsing a data
element which appears to be numeric. This particular error message is used when
the Receiver cannot detect a more specific error.

-121

Invalid character in number

An invalid character for the data type being parsed was encountered. For example, a
"9" in ocatal data.

-123

Exponent too large

Numeric overflow.

-124

Too many digits

The mantissa of a decimal numeric data element contained more than 255 digits
excluding leading zeros.

-128

Numeric data not allowed

A legal numeric data element was received, but the Receiver does not accept one in
this position for the header.

-131

Invalid suffix

The suffix does not follow the syntax described in IEEE 488.2 or the suffix is
inappropriate for the Receiver.

-134

Suffix too long

The suffix contained more than 12 characters.

-138

Suffix not allowed

A suffix was encountered after a numeric element that does not allow a suffix.

-141

Invalid character data

The character data element contains an invalid character.

-148

Character data not allowed

A legal character data element was encountered where prohibited by the Receiver.

-150

String data error

This error can be generated when parsing a string data element. This particular error
message is used if the Receiver cannot detect a more specific error.

-151

Invalid string data

A string data element was expected but was invalid for some reason.

-158

String data not allowed

A string data element was encountered but was not allowed by the Receiver at this
point in parsing.

-170

Expression error

This error can be generated when parsing an expression data element. It is used if
the Receiver cannot detect a more specific error.

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A-7

Appendix A Error Messages
List of Errors

Table A-2. Error Messages (Continued)
Number

Error String

Cause

-178

Expression data not allowed

Expression data was encountered but was not allowed by the Receiver at this point
in parsing.

-200

Execution error

This is the generic syntax error if the Receiver cannot detect more specific errors.

-220

Parameter error

Indicates that a program data element error occurred. This error is used when the
Receiver cannot detect more specific errors.

-221

Settings conflict

Indicates that a legal program data element was parsed but could not be executed
due to the current Receiver state.

-222

Data out of range

Indicates that a legal program data element was parsed but could not be executed
because the interpreted value is outside the legal range defined by the Receiver.

-223

Too much data

Indicates that a legal program data element of block, expression, or string type was
received that contained more data than the Receiver could handle due to memory or
related receiver-specific requirements.

-224

Illegal parameter value

Used where exact value, from a list of possible values, was expected (but not
received).

-230

Data corrupt or stale

No valid data available.

-240

Hardware error

Indicates that a legal program command or query could not be executed because of
a hardware problem in the Receiver.

-241

Hardware missing

Indicates that a legal program command or query could not be executed because of
missing Receiver hardware.

-300

Device-specific error

This is the generic device-dependent error.

-310

System error

Indicates that a system error occurred.

-311

Memory error

Occurs on EEPROM write failure.

-315

Configuration memory lost

Could happen on powerup or preset if a nonvolatile memory problem is detected.

-321

Out of memory

Indicates that the Receiver has detected that insufficient memory is available.

-330

Self-test failed

Indicates at least one failure occurred when *TST? or :DIAG:TEST? was executed.

-350

Queue overflow

An error occurred but was not recorded because the error queue is full.

-360

Communication error

This is the generic communication error for devices that cannot detect the more
specific errors described for errors -361 through -363.

-361

Parity error in program
message

Parity bit not correct when data received for example, on a serial port.

-362

Framing error in program
message

A stop bit was not detected when data was received. For example, on a serial port
(for example, a baud rate mismatch).

-363

Input buffer overrun

Software or hardware input buffer on serial port overflows with data caused by
improper or nonexistent pacing.

-440

Query UNTERMINATED
after indefinite response

Indicates that a query was received in the same program message after a query
requesting an indefinite response (e.g., *IDN? or :PTIM:TCOD? or :SYST:STAT?).

.

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B

Command Syntax and Style

Appendix B Command Syntax and Style
Appendix Contents

Appendix Contents
This appendix provides an overview of the Standard Commands for
Programming Instrument (SCPI) syntax and style to help you program
the Receiver. A section that lists SCPI reference documentation is also
provided.
This appendix is organized as follows:
•

•

B-2

Command Types, Format, and Elements

page B-3

–

Command Types

page B-3

–

Command Formats

page B-3

–

Elements of SCPI Commands

page B-4

–

Using Multiple Commands

page B-7

–

Elements of Response Messages

page B-9

Reference Documentation

page B-12

Operating and Programming Guide

Appendix B Command Syntax and Style
Command Types, Format, and Elements

Command Types, Format, and Elements
Command Types
There are two types of GPS Receiver programming commands: IEEE
488.2 Common Commands and Standard Commands for
Programmable Instruments (SCPI). The IEEE 488.2 Common
Commands control and manage communications between the
Receiver and the controller, terminal, or personal computer. The SCPI
commands control instrument functions. The format of each type of
command is described in the following paragraphs.

Command Formats
Common Command Format
The IEEE 488.2 Standard defines the Common commands as
commands that perform functions like reset, self-test, status byte
query, and identification. Common commands always begin with the
asterisk (*) character, and may include parameters. The command
keyword is separated from the first parameter by a space character.
Some examples of Common commands are as follows:
*IDN?

*ESE 32

SCPI Command and Query Format
SCPI commands perform functions like instrument setup. A subsystem
command has a hierarchical structure that usually consists of a top
level (or root) keyword, one or more lower-level keywords, and
parameters. The following example shows a command and its
associated query:
:GPS:POSition:SURVey:STATe ONCE
:GPS:POSition:SURVey:STATe?
GPS is a root-level keyword with POSition the second-level keyword,
SURVey the third-level keyword, and STATe the fourth-level. ONCE is
the command parameter.

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Appendix B Command Syntax and Style
Command Types, Format, and Elements

Elements of SCPI Commands
A program command or query is composed of functional elements that
include a header (keywords with colon separators), program data, and
terminators. These elements are sent to the Receiver over the serial
interface as a sequence of ASCII characters. Examples of a typical
Common Command and Subsystem Command are:
*CLS
:SYST:ERR?

Common Command Syntax
Figure B-1 shows the simplified syntax of a Common Command.
You must use a space (SP) between the command mnemonic and the
parameter in a Common Command.
sp

mnemonic

*

parameter

?
NOTE: sp = space. ASCII character decimal 32

Figure B-1. Simplified Common Command Syntax Diagram

Subsystem Command Syntax
Figure B-2 shows the simplified syntax of a Subsystem Command.
You must use a space (SP) between the last command mnemonic and
the first parameter in a Subsystem Command. Note that if you send
more than one parameter with a single command, you must separate
adjacent parameters with a comma.
,

:
:

sp

mnemonic
?

parameter
suffix

NOTE: sp = space. ASCII character decimal 32

Figure B-2. Simplified Program Command Syntax Diagram

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Appendix B Command Syntax and Style
Command Types, Format, and Elements

Abbreviated Commands
The command syntax shows most keywords as a mixture of upper and
lower case letters. Upper case letters indicate the abbreviated spelling
for the command. For better program readability, you may send the
entire keyword. The Receiver accepts either command form and is not
case sensitive.
For example, if the command syntax shows SYNChronization, then
SYNC and SYNCHRONIZATION are both acceptable forms.
Other forms of SYNChronization, such as SYNCHR or SYNCHRONIZ
will generate an error. You may use upper and/or lower case letters.
Therefore, SYNCHRONIZATION, synchronization, SyNchROnizatioN,
and SYnC are all acceptable.

Keyword Separator
A colon (:) always separates one keyword from the next lower-level
keyword as shown below:
:SYST:ERR?

Parameter Data Types
Table B-1 contains explanations and examples of parameter types.
Parameter types may be numeric value, Boolean, literal, NRf, string,
or non-decimal numeric.
Table B-1. Command and Query Parameter Types
TYPE

EXPLANATIONS AND EXAMPLES



Accepts all commonly used decimal representation of numbers including optional signs,
decimal points, and scientific notation:
123, 123e2, -123, −1.23e2, .123, 1.23e−2, 1.23000E−01.
Special cases include MINimum and MAXimum as follows:
MINimum selects minimum value available.
MAXimum selects maximum value available.
Queries using MINimum or MAXimum return the associated numeric value.



Represents a single binary condition that is either true or false:
1 or ON, 0 or OFF (Query response returns only 1 or 0.)
An  is rounded to an integer. A non-zero value is interpreted as 1.



Selects from a finite number of choices. These parameters use mnemonics to represent
each valid setting. An example of a  parameter is: GPS



Flexible numeric representation. Only positive integers are used for NRf parameters in
the instrument.



A string parameter is delimited by either single quotes or double quotes. Within the
quotes, any characters in the ASCII B-bit code may be specified.



Format for specifying hexadecimal (#H1F), octal (#Q1077), and binary (#B10101011)
numbers using ASCII characters. May be used in :STATus subsystem commands.

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Appendix B Command Syntax and Style
Command Types, Format, and Elements

Parameter Separator
If you send more than one parameter with a single command, you must
separate adjacent parameters with a comma.

Query Parameters
All selectable  parameters can be queried to return
the minimum or maximum values they are capable of being set to by
sending a MINimum or MAXimum parameter after the “?.”
For example, consider the :GPS:REF:ADEL? query.
If you send the query without specifying a parameter
(:GPS:REF:ADEL?), the present antenna delay value is returned.
If you send the MIN parameter (using :GPS:REF:ADEL? MIN),
the command returns the minimum value currently available. If you
send the MAX parameter, the command returns the maximum value
currently available. Be sure to place a space between the question
mark and the parameter.

Suffixes
A suffix is the combination of suffix elements and multipliers that can
be used to interpret the  sent. If a suffix is not
specified, the Receiver assumes that  is unscaled
(that is, Volts, seconds, etc.)
For example, the following two commands are equivalent:
:GPS:REF:ADELay 100 NS
:GPS:REF:ADELay 100E-9

Suffix Elements
Suffix elements, such as HZ (Hertz), S (seconds), V (Volts), OHM
(Ohms), PCT (percent), and DEG (degrees) are allowed within this
format.

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Appendix B Command Syntax and Style
Command Types, Format, and Elements

Suffix Multipliers
Table B-2 lists the suffix multipliers that can be used with suffix
elements (except PCT and DEG).
Table B-2. Suffix Multipliers
DEFINITION

MNEMONIC

1E9

G

1E6

MA (or M for OHM and HZ)

1E3

K

NAME
GIGA
*

MEGA
KILO

*

1E-3

M (except for OHM and HZ)

1E-6

U

MICRO

1E-9

N

NANO

1E-12

P

PICO

MILLI

* The suffix units, MHZ and MOHM, are special cases that should not be confused with
HZ and OHM.

Command Terminator
A command may be terminated with a line feed (ASCII LF character
10 decimal), a carriage return (ASCII CR character 13 decimal), or one
followed immediately by the other in any order.

Using Multiple Commands
Program Messages
Program Messages are a combination of one or more properly
formatted SCPI Commands. Program messages always go from the
DTE to the Receiver. They are sent to the Receiver over the Receiver’s
serial interface as a sequence of ASCII characters.

Program Message Syntax
Figure B-3 shows the simplified syntax of a program message. You can
see Common Commands and Subsystem Commands in the same
program message. If you send more than one command in one message,
you must separate adjacent commands with a semicolon.

Operating and Programming Guide

B-7

Appendix B Command Syntax and Style
Command Types, Format, and Elements

;

Subsystem Command




Common Command






NOTE:
 = ASCII character decimal 10
 = ASCII character decimal 13

Figure B-3. Simplified Program Message Syntax Diagram
When using IEEE 488.2 Common commands with SCPI Subsystem
commands on the same line, use a semicolon between adjacent
commands. For example:
*CLS;:SYST:ERR?
When multiple SCPI Subsystem commands are sent in one program
message, the first command is always referenced to the root node.
Subsequent commands, separated by “;”, are referenced to the same
level as the preceding command if no “:” is present immediately after
the command separator (the semicolon).
For example, sending
:GPS:INIT:DATE 1994,7,4;TIME 12,34,56
is equivalent to sending:
:GPS:INIT:DATE 1994,7,4
:GPS:INIT:TIME 12,34,56
or
:GPS:INIT:DATE 1994,7,4;:GPS:INIT:TIME 12,34,56
The “:” must be present to distinguish another root level command.
For example:
:SYNC:HOLD:DUR?;:GPS:SAT:VIS:PRED?
is equivalent to sending:
:SYNC:HOLD:DUR?
:GPS:SAT:VIS:PRED?

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Appendix B Command Syntax and Style
Command Types, Format, and Elements

If the “:”(which is following the “;” and is in front of GPS) is omitted,
the Receiver assumes that the second command is
:SYNC:HOLD:GPS:SAT:VIS:PRED?
and generates a syntax error.

Elements of Response Messages
Response Messages
Response messages are data sent from the Receiver to the DTE in
response to a query. (A query is a command followed by a question
mark. Queries are used to find out how the Receiver is currently
configured and to transfer data from the Receiver to the DTE.)
After receiving a query, the Receiver interrogates the requested
configuration and issues its response message as soon as possible.
The message is transmitted across the serial interface to the DTE.

Response Message Syntax
Figure B-4 shows the simplified syntax of a Response Message.
Response messages may contain both commas and semicolon
separators. When a single query command returns multiple values,
a comma is used to separate each item. When multiple queries are sent
in the same program message, the groups of data corresponding to
each query are separated by a semicolon.
;
,
response data





NOTE:
 = ASCII character decimal 10
 = ASCII character decimal 13
; = multiple response separator (ASCII character decimal 59)
, = data separator within a response (ASCII character decimal 44)

Figure B-4. Simplified Response Message Syntax Diagram

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Appendix B Command Syntax and Style
Command Types, Format, and Elements

Response Formats
Table B-3 contains explanations of response formats.
Table B-3. Response Formats
Format

Description

± dd

This numeric format represents an integer (e.g., +9).

+


−
The maximum number of characters in ±dd response data is 17 (maximum
16 digits, 1 sign).
± dd, ...

This numeric format represents a comma-separated list of integers
(e.g., +1,+2,+3).

± d.d

This numeric format represents a fixed (e.g., +10.5).

+


.



−
± d.dEe

This numeric format represents a floating-point number (e.g., +1.00E+000).

+


.



−
+
E



−

The maximum number of characters in ±d.dEe response data is 13 (maximum
6 mantissa digits, 2 signs, 1 decimal point, 1 'E' character, 3 exponent digits).
± d.dEe,

This numeric format represents comma-separated list of floating-numbers
(e.g., +1.00000E-009, +2.00000E-009, +5.00000E-009).

0 or 1

A single ASCII-encoded byte, 0 or 1, is returned for the query of settings that
use ON, OFF, 1, or 0 parameters.

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Appendix B Command Syntax and Style
Command Types, Format, and Elements

Table B-3. Response Formats (Continued)
Format

Description

XYZ

ASCII-encoded bytes corresponding to the literal used as the command
parameter.

alpha
alpha
digit

An example of an alphanumeric response is: NONE
“XYZ ”

A string response consists of ASCII characters enclosed by double quotes.
For example, string data is used for the “” portion of
:SYST:ERR? response.

“XYZ”, ...

A list of string responses consist of comma-separated ASCII characters
enclosed by double quotes.
(e.g., “log 224:19951017.00:00:26:30: Holdover started, GPS”,
“log 225:19951017.00:00:29:02: GPS lock started”)

ASCII Data

A sequence of ASCII-encoded bytes.

Binary Data

The syntax is a pound sign (#) followed by a non-zero digit representing the
number of digits in the subsequent decimal integer. The decimal integer
specifies the number of 8-bit data bytes being sent. This is followed by the
actual data. The terminator is a line feed. For example, for transmitting 8 bytes
of data, the format might be:
Number of digits
that follow
Actual data

Terminator

# 2 08<8 bytes of data> 
Number of bytes
to be transmitted

The “2” indicates the number of digits that follow and the two digits “08” indicate
the number of data bytes to be transmitted.
 is defined as a single ASCII-encoded byte corresponding to
13 decimal.
 is defined as a single ASCII-encoded byte corresponding to
10 decimal.

Operating and Programming Guide

B-11

Appendix B Command Syntax and Style
Reference Documentation

Reference Documentation
This section contains a list of documentation related to the use of the
Receiver’s RS-232C serial port. Additional information that you may
find useful can be found in the following publications:
1. Beginner’s Guide to SCPI (HP Part Number H2325-90001,
July 1990 Edition).
2. Beginner’s Guide to SCPI, Barry Eppler (Hewlett-Packard
Press, Addison-Wesley Publishing Co. 1991).
3. Standard Commands for Programmable Instruments
(SCPI), Version 1992.0.
This standard is a guide for the selection of messages to be included
in programmable instrumentation. It is primarily intended for
instrument firmware engineers. However, you may find it useful if
you are programming more than one instrument that claims
conformance to the SCPI standard. You can verify the use of
standard SCPI commands in different instruments.
To obtain a copy of this standard, contact:
SCPI Consortium
8380 Hercules, Suite P3
La Mesa, CA 91942
Phone: (619) 697-8790
FAX: (619) 697-5955
4. The International Institute of Electrical Engineers and
Electronic Engineers, IEEE Standard 488.2-1987, IEEE
Standard Codes, Formats, Protocols, and Common
Commands for Use with ANSI/IEEE Std 488.1-1987
Programmable Instrumentation.
This standard defines the underlying message formats and data
types used in SCPI. It is intended more for firmware engineers
than for instrument users/programmers. However, it can be useful
if you need to know the precise definition of specific message
formats, data type, or common commands.
To obtain a copy of this standard, write to:
The Institute of Electrical and Electronic Engineers Inc.
345 East 47th Street
New York, NY 10017 USA

B-12

Operating and Programming Guide

C

Receiver Firmware Installation

Appendix C Receiver Firmware Installation
Downloading New Firmware Using SatStat Program

Downloading New Firmware Using
SatStat Program
1 Copy the file of the updated firmware disk to a directory on your PC
disk drive.
If you haven’t already installed SatStat, you should install it now
(follow instructions on the disk label or in the section titled “To Install
the Automated SatStat Program for Continual Status Updates” in
Chapter 3, “Visual User Interface,” of this guide).
2 Start SatStat (easiest way is to double-click on the icon).
3 You should establish communication with the GPS Receiver.
This requires connection from a serial RS-232 port on your PC to the
GPS Receiver’s serial port (a 25-pin RS-232 connection). Assuming
you’ve got the cable attached to make this connection, you may want to
check the settings.
a. Select CommPort, then choose Settings.
The Communication Settings dialog box is displayed. Unless
someone has reprogrammed the CommPort settings on the GPS
Receiver, these settings are probably OK. The one setting that is
likely to need changing is the Com Port. The application defaults it
to Com1, but the serial port on your PC may be assigned to a
different Com Port. Select the appropriate setting. If you are unsure,
Com1 will be your best bet (worst case, you can cycle through all of
them until it works).
b. If you made any changes on this form, select OK, otherwise you can
just Cancel.
4 Select CommPort, then choose Port Open.
The main form of the Receiver Status screen is displayed.
The application will send some commands to the GPS Receiver and
then the main form should begin to periodically update every few
seconds. If you are getting screen updates, proceed to the next step.
Otherwise, something is wrong with your CommPort settings or
perhaps the physical connection between your PC and the GPS
Receiver.

C-2

Operating and Programming Guide

Appendix C Receiver Firmware Installation
Downloading New Firmware Using SatStat Program

NOTE

Prior to download, interrogate the product, record any custom
configuration parameters. This step is necessary because
downloading new instrument firmware will reset all
parameters to system-preset defaults. Parameters typically
recorded include:
•

antenna delay

•

elevation mask angle

•

timezone offset

A table of all system-preset defaults is printed in Table 5-2 on
page 5-111 in Chapter 5 of this guide; refer to it to identify
additional parameters whose default values are inappropriate
for your application. Record the settings you use prior to
download.
5 Performing the download works best if the periodic updates are
disabled. On the main form, select the Function menu, choose Status
(check mark appears), and choose Disable Updates (check mark
appears).
6 Activate the form titled “Control & Query” by clicking anywhere on it.
Select Service, then choose Download Firmware. This will bring up a
form titled “Firmware Download”.
7 Now you need to select the file that you will download. Select the
control labeled File.
This brings up a form for file selection. Download files for the GPS
Receiver have a .s appended to the file name. This form is set to only
find .s type files. In this case, you want to find and select the filename,
for example s_3503.s. Depending on where you have placed this file,
you may have to use this form to navigate for it. If it is on a different
drive, use the Drives selection in the lower right. Once you’ve located
s_3503.s select it (clicking on the name is probably the easiest) and
then select OK. The file, along with its path should now appear in the
“File to Download” portion of the “Firmware Download” form.
8 You’re now ready to perform the download. Select the control titled
Download and an erase warning will appear. This is just a
double-check to make sure you really want to do this. Assuming you do,
select Yes, Perform the Download.
The program will switch the GPS Receiver to the “INSTALL” language,
erase the flash memory, and begin downloading S-records. The
S-records are the long character strings that appear in the lower part
of the form as the downloading process proceeds. The total
Operating and Programming Guide

C-3

Appendix C Receiver Firmware Installation
Downloading New Firmware Using SatStat Program

downloading time varies depending on the type of PC you have, but
with communication settings optimized a typical time is about
30 minutes. Once the download is under way, an estimate of the time
to complete the process is updated every 100 S-records.
9 When the downloading has completed, the “Minutes Until Finished”
field will say “DONE”. You can then select Close on the Firmware
Download form.
There are a couple of ways to confirm that the new firmware has been
installed; the easiest is to just power-cycle the unit. Once it has
powered up, you can confirm that the new revision is in place by
selecting Query, then choosing Product ID (from the “Control & Query”
form) and selecting Send Cmd. The product ID will appear on the
Control & Query form and should contain the new date code “3503”,
for example. An alternative way to check the download is to type
SYST:LANG "PRIMARY" in the edit field on the “Control & Query”
form and select Send Cmd. This will return the unit to normal
operating mode without power-cycling. If you do this, you could then
check the product ID as described above. NOTE: it is expected that in
early software revisions the alarm will come on the first time you
power-cycle (or switch to “primary” using SYST:LANG “PRIMARY”).
If you investigate the alarm, you will find it is the software
safeguard—it has gone off because you have changed the instrument
firmware. On subsequent power-ons the alarm will not come on.
After upgrading instrument firmware, you will need to restore the
instrument settings recorded prior to the download, and restore the
instrument and PC communications settings so that BAUD rate and
echo are set according to the requirements of your installation.

C-4

Operating and Programming Guide

D

Performance Tests
Verifying Specifications

Appendix D Performance Tests
Introduction

Introduction
This appendix provides procedures to test the electrical performance of
the 58503B and 59551A GPS Receivers specifications listed in and
Appendix E, “58503B Specifications,” and Appendix F, “59551A
Specifications,” of the. Two types of testing are provided:
•

Operational Verification, starting on page D-5

•

Complete Performance Tests, starting on page D-17

Operational Verification
The Operational Verification operational verification test is an
abbreviated series of checks that may be performed to give a high
degree of confidence that the instrument is operating properly without
performing the Complete Performance Tests. An operational
verification is useful for incoming inspection, routine maintenance, and
after instrument repair.

Complete Performance Tests
The Complete Performance Tests performance tests verify the
specifications listed in Appendix E, “58503B Specifications or
Appendix F, “59551A Specifications.” All tests can be performed
without access to the inside of the instrument.

Test Record
The results of the Operational Verification and Complete Performance
Tests should be recorded on a copy of the appropriate (i.e., 58503B or
59551A) Performance Test Record, located at the end of this chapter.

D-2

Operating and Programming Guide

Appendix D Performance Tests
Equipment Required

Equipment Required
Table D-1. Recommended Test Equipment
Instrument

Required Characteristics

Recommended Model

Use*

Digitizing
Oscilloscope

2 channels
500 MHz bandwidth (repetitive)

HP 54600B (or
equivalent)

OV, P

Digital Multimeter
(DMM)

Microvolt accuracy with leads

HP 34401A (or
equivalent)

OV, P

Terminal or
computer

Communication Software, RS-232C
connection

Any Model

OV, P

Universal Counter

Resolution: 300 ps or better in T.I.
Mode

HP 53132A (or
equivalent)

P

Frequency Standard

1 PPS Source. Jitter: <1 ns rms
pulse-to-pulse

HP 5071A (or equivalent)

P

HP 10100C (or
equivalent)

OV

50Ω Coaxial Cable
BNC(m) to BNC(m), 48 inches
with BNC connectors

HP 10503A (or
equivalent)

P

GPS Antenna or
Antenna Assembly

58504A or 58513A

P

10 MHz House Standard. Accuracy:
2X10-12 or better
50Ω Feedthrough

____________________________

____________________________

GPS Antenna Cable
Assembly

RG-213 or LMR 400 cables with
TNC (m)-to-N (m) connectors

58518A, 58520A

P

Antenna
Interconnect Cable
Assembly

RG-213 or LMR 400 cables with
N (m)-to-N (m) connectors

58519A, 8521A

P

Barrel adapter

N (f)-to-N (f)

HP 1250-0777 (or
equivalent)

P

*OV = Operational Verification
P = Performance Tests
T = Troubleshooting

Operating and Programming Guide

D-3

Appendix D Performance Tests
Before You Start

Before You Start
The time required to acquire lock as described in the following section
can vary significantly depending on your local conditions. In general, it
is strongly recommended that your antenna and cables be set up in
accordance with the information provided in the documents listed
below prior to performing any of the tests that follow, or the results
cannot be assumed to be valid.
Documents providing GPS Antenna System information are:
•

Designing Your GPS Antenna System Configuration Guide
configuration guide, which discusses the components of an
GPS timing receiver system and how to custom design the
configuration of your antenna system. Contact your local Sales
office for a copy of this guide.

•

Information Notes that provide installation procedures for the
applicable GPS antenna and accessories that you purchase.

Acquiring lock does not mean that the unit is fully operational and
meeting specifications. It just means that the GPS Receiver has
detected enough satellites to start its survey mode to determine its
precise location. An Internal measurement FFOM (Frequency Figure
of Merit) becomes 0 when the internal loops reach their proper time
constants, indicating that the output frequency and 1 PPS signals are
now fully operational and meeting their specifications. Under the
worst conditions, the GPS Receiver may take 24 to 72 hours to achieve
FFOM = 0. FFOM can be monitored in the Reference Outputs
quadrant of the Receiver Status screen (see the sample status screen,
Figure 3-1, in Chapter 3, “Visual User Interface,” of this guide if
needed). Also, using :PTIMe:TCODe? query command will provide the
FFOM value.

D-4

Operating and Programming Guide

Appendix D Performance Tests
Operational Verification

Operational Verification
Introduction
The 58503B and 59551A GPS Receivers are designed to automatically
detect and acquire satellites in order to begin providing precise
frequency and time information.
Until such acquisition is complete and the unit is locked with
FFOM = 0, the signals produced on the rear panel are not precise.
However, it is possible to verify that the Receiver has been received in
good working condition by performing some simple operational
verification tests upon receipt.
Except for two tests (Time Stamp Verification and Programmable
Pulse Verification), all of the following operational verification tests do
not require usage of the GPS antenna. These tests are designed to
provide a high degree of confidence that the Receiver is functioning,
but the tests will not verify the specified performance characteristics.
Such testing requires more expensive equipment and very long test
times (over 72 hours per unit). We recommend that full or complete
Performance Testing be restricted to testing only after any repairs to
the 58503B or 59551A.
The 58503B and 59551A require no calibration.
Record the results of the Operational Verification in the
appropriate place on the appropriate (i.e., 58503B or 59551A)
Performance Test Record, which is located at the end of this
chapter.

Power-Up Procedure
NOTE

Use the HP 10100C 50Ω feedthrough on the input of the oscilloscope
for the following test.
1 Connect the Receiver to a suitable power source. The unit will perform
a self-test of internal components.
2 Verify that after 15 seconds the Power indicator is on and the Alarm
indicator is off. This ensures that all internal components and
connections are functioning. (If needed, refer to the subsection titled
“To Connect Power” in Chapter 1 of the 58503B/59551A Getting
Started Guide for assistance in connecting the Receiver to a power
source.)

Operating and Programming Guide

D-5

Appendix D Performance Tests
Operational Verification

10 MHz Verification (58503B Only)
1 Set the HP 54600B oscilloscope or equivalent sweep rate to 100 ns/div,
input amplitude to 0.2 Volts/div, and input coupling to ac.
2 Connect the oscilloscope to the rear-panel 10 MHz OUT output of the
58503B as shown in Figure 2.

HP 54600B
Oscilloscope or equivalent

58503B
GPS Receiver
(Rear Panel)

!

ANT

!

50Ω Feedthrough
(HP 10100C)

!

10 MHz
BNC Cable

Figure D-1. 58503B 10 MHz Operational Verification Setup
3 Verify that there is a 10 MHz sine wave present with approximately
1 Volt peak-to-peak into the 50 ohm load.
4 Mark Pass or Fail in Line 1 on the Operational Verification portion of
the 58503B Performance Test Record, located at the end of this
chapter.

1 PPS Verification
1 Set the oscilloscope sweep rate to 5 µs/div, input amplitude to 5 Volts,
and input coupling to dc.
2 Connect the oscilloscope to the rear-panel 1 PPS output of the Receiver
as shown in Figure D-2.

D-6

Operating and Programming Guide

Appendix D Performance Tests
Operational Verification

HP 54600B
Oscilloscope or equivalent

58503B
GPS Receiver
(Rear Panel)

!

ANT

!

!

50Ω Feedthrough
(HP 10100C)

1PPS
BNC Cable

OR
1PPS

!

!

!

!

59551A
GPS Receiver
(Rear Panel)

Figure D-2. 1 PPS Operational Verification Setup
3 Verify the presence of a TTL level pulse with approximately 20 µs pulse
width.
4 Mark Pass or Fail in Line 2 on the Operational Verification portion of
the appropriate ( 58503B or 59551A) Performance Test Record, located
at the end of this chapter.

IRIG-B Verification (59551A Only)
1 Set the oscilloscope sweep rate to 1 msec/div and input amplitude to
5 Volts/div, dc-coupled.
2 Connect the oscilloscope to the rear-panel IRIG-B output of the 59551A
GPS Receiver as shown in Figure 2.
Verify that the display shows a sine wave with a period of 1 ms,
changing in amplitude from 5 Volts peak-to-peak, to greater than
10 Volts peak-to-peak. This is the IRIG-B time code modulating a
1 kHz carrier.
3 Mark Pass or Fail in Line 3 on the Operational Verification portion of
the 59551A Performance Test Record, located at the end of this
chapter.
Operating and Programming Guide

D-7

Appendix D Performance Tests
Operational Verification

HP 54600B
Oscilloscope or equivalent

59551A
GPS Receiver
(Rear Panel)

IRIG-B

!

!

!

!

50Ω Feedthrough
(HP 10100C or equivalent)

BNC Cable

Figure D-3. 59551A IRIG-B Operational Verification Setup

Time of Day and PORT 1 RS-232C Serial Interface
Verification
1 Connect a terminal or computer (set to 9600 baud, 8 data bits, 1 stop
bit, and no parity and no pace) to the rear-panel PORT 1. If you need
assistance in setting the serial parameters, refer to the Getting Started
guide.
2 Press the Return key on the terminal.
Verify that either a SCPI > or E-xxx> prompt is returned. The xxx can
be any number for this test. If E-xxx> is returned, send the *CLS
command to clear the error.
3 Type :SYSTEM:STATUS?, then press Enter (or Return) key.
The terminal screen displays the Receiver Status screen, which is a
complete status report of the Receiver. Without a GPS antenna, most
data will be blank or indicating that the instrument is in “Power-Up”
mode. The FFOM = 3 in the upper right corner indicates that the
Receiver is in power-up mode and frequency outputs are invalid. At
this point, the data at the bottom of the screen lists the results of all
internal self-tests. The HEALTH MONITOR, SelfTest, Int Pwr,
Oven Pwr, OCXO, EFC, and GPS Rcv should all show OK.
4 From the terminal keyboard, type
:PTIME:TCODE? and press Return.

D-8

Operating and Programming Guide

Appendix D Performance Tests
Operational Verification

An alphanumeric string which starts with a “T” should be displayed as
shown in the following example:
T2199505112055233000049
Note that the value above will be different for each test, depending on
the local date and time.
5 Mark Pass or Fail in Line 4 on the Operational Verification portion of
the appropriate (58503B or 59551A) Performance Test Record, located
at the end of this chapter.

Antenna Power Verification
1 Set the DMM to read a range of 5 Volts dc.
2 Measure the dc voltage from the center pin of the antenna (Type N)
connector with respect to the threaded connector shell.
Verify that the voltage is between 4.5 and 5.0 Volts dc.
3 Mark Pass or Fail in Line 5 on the Operational Verification portion of
the appropriate (58503B or 59551A) Performance Test Record, located
at the end of this chapter.
4 If you are testing the 58503B with Option 001 Front Panel and
Keypad, perform the procedure in the following section titled “Front
Panel Display/Keypad Verification (58503B Option 001 Only)” on
page D-10.
If you are testing the standard 58503B, go to the section titled
“Operational Verification Conclusion” on page D-15 in this chapter.
If you are testing a 59551A, go to the section titled “Time Tagging
(Stamping) Verification and Programmable Verification (59551A
Only)” on page D-11.

Operating and Programming Guide

D-9

Appendix D Performance Tests
Operational Verification

Front Panel Display/Keypad Verification (58503B
Option 001 Only)
This tests the operation of the Front Panel Display/Keypad option for
the 58503B.
1 Disconnect and re-apply power to the 58503B.
2 While the letters "HP" are moving from right to left (about 2 seconds),
press Sat key and then Time key to enter the TEST/DEMO mode.
3 The words VFD DSP TEST will momentarily appear.
The display should then show a test pattern that sequentially
illuminates all 15 segments of all digits and punctuation marks in the
display.
4 Verify that all segments illuminate.
5 When the segment illumination sequence is complete, the words
DEMO MODE should then appear.
6 Press each key one at a time. Each keypress should:

NOTE

•

illuminate the LED corresponding to that key, and

•

display a simulated response to the function.

(1) The Clear Alarm (Shift , Alt) function will exit the test. (2) The
values displayed are not related to the 58503B under test. They are
displayed for demonstration only.

7 To exit the diagnostic, press Shift key, and then press Alt key.
8 The 58503B power-up sequence should then continue. No further tests
are necessary.
9 Mark Pass or Fail in Line 5 on the Operational Verification portion of
the 58503B Performance Test Record, located at the end of this
chapter.
10 Proceed to the section titled“Operational Verification Conclusion” on
page D-15 to complete the operational verification.

D-10

Operating and Programming Guide

Appendix D Performance Tests
Operational Verification

Time Tagging (Stamping) Verification and
Programmable Verification (59551A Only)
NOTE

GPS ANTENNA REQUIRED. The steps below require that a GPS
antenna be properly set up, and the 59551A is in GPS locked mode
before proceeding. For information on how to make such a setup, refer
to the antenna information provided on page D-4 in this chapter.
If you determine that these tests will not be performed for your facility,
please proceed to the next section titled “Operational Verification
Conclusion” on page D-15.

1 Connect a GPS Antenna and cable to the 59551A and allow the
Receiver to indicate it is in “GPS Lock” mode as indicated by the
illuminated GPS Lock indicator. Until GPS lock is attained, the
following tests will not be valid. Your test setup should be similar to
Figure 1.

GPS
Antenna
Terminal or Computer

!

!

!

!

59551A
GPS Receiver
(Rear Panel)

Figure D-4. 59551A Time Tagging Operational Verification Setup
2 Enter the following commands from the terminal or computer to note
the current date and time.
:PTIME:DATE?
:PTIME:TIME?
3 On the computer or terminal, type :SENSE:DATA:CLEAR and press the
Return key.

Operating and Programming Guide

D-11

Appendix D Performance Tests
Operational Verification

This clears the Time Tagging event registers of any data prior to the
next step.
4 On the computer or terminal, type :FORMAT:DATA ASCII and press the
Return key.
This sets the output format of the Time Tagging Data to an ASCII
string for easier interpretation.
5 Refer to Chapter 2, “Features and Functions,” in the 58503B/59951A
Getting Started Guide to identify types of stimulus equipment that
could be used for this test.
A suggested general-purpose device could be a pulse generator, set to
output a TTL level pulse.
6 Use this signal to send an event to each of the three Time Tagging
inputs.
7 From the terminal or computer, send the following query commands to
verify that an event was recorded in each of the Time Tagging event
registers. Note that there is a space between the question mark (?) and
the quotation mark (“) in the following commands.
:SENSE:DATA? “TSTAMP 1”
:SENSE:DATA? “TSTAMP 2”
:SENSE:DATA? “TSTAMP 3”

Note that the actual date and time of the record is not being tested.
8 Verify that each response is the following format:
yyyy,mm,dd,hh,mm,ssssssss,xxxxxxxxxx
9 On the terminal, type :SENSE:DATA:CLEAR and press the Return key.
10 This again clears the Time Tagging event registers of any data from
this test.
11 Mark Pass or Fail in Line 6 on the Operational Verification portion of
the 59551A Performance Test Record, located at the end of this
chapter.

D-12

Operating and Programming Guide

Appendix D Performance Tests
Operational Verification

Programmable Pulse Verification (59551A Only)
1 Enter the following commands from the terminal or computer:
:PULSE:CONTINUOUS:PERIOD 1
This sets the period to 1 second.
:PULSE:CONTINUOUS:STATE ON
This sets the programmable pulse output to provide a continuous
stream of pulses.
:PULSE:START:DATE , , 
2 Set the year, month, and day to the same values read in step 2 in the
previous procedure “Time Tagging Verification.”
Example:
:PULSE:START:DATE 1995, 7, 25 is July 25, 1995.
:PULSE:START:TIME , , 
3 Set the hours, minutes, and seconds to the same values observed in
step 2 of the previous procedure “Time Tagging Verification.”
Example:
:PULSE:START:TIME 13, 1, 5 is 13:01:05 in 24-hour format.
NOTE

Setting the time to a value earlier than the present time will start the
pulse stream immediately. If a time is input with a value some time in
the future, the pulse stream will not start until that time is attained.

4 Set the oscilloscope sweep rate to 5 msec/div, input amplitude to
5 Volts/div, and input coupling to dc.
5 Connect the oscilloscope to the rear-panel Programmable Pulse output
as shown in Figure 5.

Operating and Programming Guide

D-13

Appendix D Performance Tests
Operational Verification

GPS
Antenna

HP 54600B
Oscilloscope or equivalent

Programmable Pulse

!

!

!

!

50Ω Feedthrough
(HP 10100C)

Terminal or Computer

BNC Cable

59551A
GPS Receiver
(Rear Panel)

Figure D-5. 59551A Programmable Pulse Operational Verification
Setup
6 Verify that a continuous stream of TTL-compatible pulses are
occurring at a 1 second rate.
7 Mark Pass or Fail in Line 7 on the Operational Verification portion of
the 59551A Performance Test Record, located at the end of this
chapter.

D-14

Operating and Programming Guide

Appendix D Performance Tests
Operational Verification

Operational Verification Conclusion
NOTE

Perform the following step only if you wish to restore memory of the
58503B or 59551A Receiver to the factory default states. Doing this can
change several parameters that have been stored by a previous user. If
you have any questions or concerns, refer to Table 5-2 under the
description of the :SYSTEM:PRESET command on page 5-111 of
Chapter 5 in this guide for information on the type of information that
is stored.

On the terminal or computer, type:
:SYSTEM:PRESET and press the Return key.
This will ensure that your Receiver has been restored to the factory
defaults as originally received.
This completes the operational verification.

Operating and Programming Guide

D-15

Appendix D Performance Tests
In Case of Difficulty

In Case of Difficulty
If any of the above tests fail it should be re-checked before assuming
that the unit is defective. Return any defective unit.

D-16

Operating and Programming Guide

Appendix D Performance Tests
Complete Performance Tests

Complete Performance Tests
The specifications of the 58503B and 59551A can be verified by
performing the Performance Tests provided in this section. Table D-2
lists a summary of the 58503B/59551A Complete Performance Tests.
Table D-2. The 58503B/59551A Complete Performance Tests
Page
Number

Time and Frequency Output Tests

D-18

Preliminary Test Setup

D-19

Test 1: 10 MHz Frequency Accuracy and 1 PPS Jitter
(Locked to GPS)

D-22

Test 2: 10 MHz Holdover Aging and 1 PPS Accumulated
Time Error (Unlocked)

D-24

Test 3: 1 PPS Time Accuracy (Locked)

D-24

Test 4: 10 MHz Frequency Stability (Time Domain) and
Phase Noise (Frequency Domain) Measurements

The following tests will ensure that the 58503B GPS Time and
Frequency Reference Receiver and 59551A GPS Measurements
Synchronization Module are meeting the published specifications.
Some of these tests will require that the Receiver be operating
continuously for at least 3 days, others require that the Receiver be
disconnected from GPS, and others will require further investigation in
order to produce a satisfactory setup and measurement.
The critical specifications to be tested are the 10 MHz Frequency
Accuracy (1 day) and the 1 PPS Jitter (1 day) specifications. As long as
the Receiver is locked, the proper performance of these two
specifications will imply that the other specifications are in
conformance.
The following tests do not test “typical” or “nominal” specifications, or
“supplemental characteristics,” “supplemental information,” or
“features.”
Record the results of the Performance Test in the appropriate
place on the appropriate (i.e., 58503B or 59551A) Performance
Test Record, which is located at the end of this chapter.

Operating and Programming Guide

D-17

Appendix D Performance Tests
Complete Performance Tests

Preliminary Test Setup
If you have not connected the GPS antenna to the Receiver, perform
the following preliminary procedure in this section.
If you have already connected the GPS antenna to the Receiver, go to
the next subsection titled “Test 1: 10 MHz Frequency Accuracy and
1 PPS Jitter (Locked to GPS).”
1 Connect the antenna system to the rear-panel ANTENNA Type-N
connector of the Receiver as described in the instructions given in the
section titled “Preparing the GPS Receiver for Use” in Chapter 1, of the
58503B/59551A Getting Started Guide.
NOTE

Do not apply power to the Receiver unless a fully operational antenna
system is connected to the ANTENNA input connector. Power applied
with no antenna input or a non-functioning antenna will initiate an
extended search process that may increase time to reach GPS lock. You
can halt the extended search by disconnecting and reconnecting
(cycling) the external supply voltage to the Receiver (you may need to
leave power disconnected for greater than five seconds).
2 Connect the Receiver to a suitable power source. (If needed, refer to the
subsection titled “To Connect Power” in Chapter 1 of the
58503B/59551A Getting Started Guide.)
3 The Receiver will perform a self-test of internal components. Verify
that after 15 seconds the Power indicator illuminates and the Alarm
indicator is off. This ensures that all internal components and
connections are functioning.

D-18

Operating and Programming Guide

Appendix D Performance Tests
Complete Performance Tests

Test 1: 10 MHz Frequency Accuracy and 1 PPS Jitter
(Locked to GPS)
This test measures the relative change in the 1 PPS pulses between
the unit under test and a known accurate source. A time interval is
measured and the data is stored to be compared with a second
measurement, 24 hours later. The 1 PPS source is derived from the
internal 10 MHz, and the relative accuracy of 1 PPS is directly related
to the accuracy of the 10 MHz.

Specifications Tested
Frequency Accuracy (locked): Better than 1 x 10-12 for a one day
average, 0 degrees to 50 degrees C.
1 PPS Jitter of leading edge: <750 ps with at least one satellite in
view, Selective Availability on.

Procedure
1 Connect the terminal or computer to the Receiver using the cable
recommended in the Getting Started Guide and ensure that they are
both communicating.
2 Ensure that the Receiver is in “GPS Lock” mode as indicated by the
illuminated GPS Lock indicator, and that FFOM = 0. The current
value of FFOM and many other characteristics of the unit can be
determined by typing :SYSTEM:STATUS? on the terminal.
3 Connect the 10 MHz reference output from the reference 1 PPS source
(HP 5071A or another stable, traceable house standard) to the
rear-panel Ref In of the Universal Counter, as shown in Figure D-6, to
provide an external timebase for the Counter.
GPS
Antenna

Ref. In (rear panel)
50Ω Feedthrough (HP 10100C)

58503B or
59551A
GPS Receiver
(Rear Panel)

HP 53132A
Universal
Counter
or equivalent

1PPS
(rear panel)

Port1
10 MHz External
Reference Out
(rear panel)

5071A
PRIMARY FREQUENCY STANDARD

Continuous
Operation

!

ANT

!

1PPS
Output

!

Channel 1

Channel 2

HP 5071A
Primary Frequency Standard or
House Standard

Figure D-6. 10 MHz Frequency Accuracy and 1 PPS Jitter Test Setup
(58503B GPS Receiver shown)
Operating and Programming Guide

D-19

Appendix D Performance Tests
Complete Performance Tests

4 Connect the rear-panel 1 PPS from Receiver under test to Channel 1 of
the Universal Counter.
5 Connect the 1 PPS from the reference standard (5071A) to Channel 2.
6 On the terminal or computer, enter the following command to clear all
entries in the Diagnostic (status) Log:
:DIAG:LOG:CLEAR and press the Enter (or Return) key.
7 Set the Universal Counter function to take 100 samples of Time
Interval and compute the Mean value. Ensure that the inputs are set
to DC-coupled, 50 Ohms, and rising edge. Set the trigger level for both
inputs to 1Volt dc.
8 Record the average time interval for later comparison.
_______________________________________ seconds.
9 Disconnect the reference 1 PPS from input 2 and set the counter to
“COMMON” mode so the 1 PPS from the Receiver is input to both
channels. For this step, be sure the trigger levels are both set to 1 Volt
dc.
10 Set the counter to compute the Standard Deviation for the same 100
samples.
This is the RMS Jitter of the 1 PPS.

D-20

Operating and Programming Guide

Appendix D Performance Tests
Complete Performance Tests

11 Again, allow the counter to accumulate 100 samples of time interval.
12 Note the largest deviation (greater or less) from exactly 1 second.
This the worst-case 1 PPS leading edge jitter.
13 Record the results of 1 PPS Jitter on Line 2 of Test 1 of the
Performance Test Record.
14 Wait 24 hours to complete the Frequency Accuracy test.
15 On the terminal or computer, enter the following command:
:DIAG:LOG:READ:ALL? and press the Enter (or Return) key.
Observe the messages (if any) that appear and verify that none of the
messages indicate that the 58503B/59551A has entered holdover mode.
If it has, the entire test must be re-started from step 2 above.
16 Repeat steps 2 through 8 above after the 24-hour period.
17 Compute the Frequency Accuracy using the following formula:

( t1 – t2 ) sec onds
---------------------------------------------- = Accuracy (unitless)
∆t sec onds

Where,
t1 is the average time interval first measured
t2 is the average time interval last measured

∆t is the time between measurements (86,400 seconds = 24 hours)
18 Record the results of Frequency Accuracy in Line 1 of Test 1 of the
Performance Test Record.

Operating and Programming Guide

D-21

Appendix D Performance Tests
Complete Performance Tests

Test 2: 10 MHz Holdover Aging and 1 PPS
Accumulated Time Error (Unlocked)
The following tests are identical to the previous tests, with the
exception that during the actual test, the Receiver is not locked to the
GPS. However, the test must adhere to the restrictions noted below
with the specification in order for the results to be valid.

Specifications Tested
Holdover aging: < 1 x 10-10/day average frequency change in 24 hours
unlocked after 3 days locked operation for any 10 degrees C range
between 10 degrees C and 40 degrees C.
Accumulated time error: <8.6 us accumulated in 24 hours unlocked
after 3 days of locked operation with a fixed antenna location, any
10 degrees C range between 10 degrees and 40 degrees C.

Procedure
1 Ensure that the Receiver has been in GPS Lock mode for at least three
(3) days without entering holdover mode by typing the following
command on the terminal or computer:
:DIAG:LOG:READ:ALL? and press the Enter (or Return) key.
Verify that there are no messages to indicate that holdover mode was
started during the last 72 hours of operation.
2 Ensure that the temperature restrictions described above will be met
for the next 24 hours.
3 Connect the 10 MHz reference output from the reference 1 PPS source
(5071A or another stable, traceable house standard) to the rear-panel
Ref In of the Universal Counter, as shown in Figure D-6, to provide an
external timebase for the Counter.
4 Connect the rear-panel 1 PPS from Receiver under test to Channel 1 of
the Universal Counter.
5 Connect the 1 PPS from the reference standard (5071A) to Channel 2.
Ensure that the inputs are set to DC-coupled, 50 Ohms, and rising
edge. Set the trigger level for both inputs to 1 Volt dc.
6 Disconnect the antenna cable (N-type connector) at the rear of the
Receiver to force it into Holdover Mode.
7 Ensure that the Holdover indicator is illuminated and the GPS Lock is
not illuminated.
D-22

Operating and Programming Guide

Appendix D Performance Tests
Complete Performance Tests

8 Note the time interval average for 100 samples, either positive or
negative.
NOTE

Do not re-connect the antenna at this time. It must remain
disconnected for the entire 24-hour period.
9 Wait 24 hours to complete the Holdover Aging test. During this
24-hour period, ensure that the temperature restrictions are
maintained. If the temperature does exceed the range, the Receiver
will have to be re-connected to the antenna, allowed to lock, run for at
least 3 days, and re-tested with this procedure.
10 Repeat steps 3, 4, 5, and 8 above after the 24 hour period.
11 If desired, re-connect the antenna cable at this time.
12 Compute the Holdover Aging rate using the following formula:

( t1 – t2 ) sec onds
---------------------------------------------- = Aging rate (unitless)
∆t sec onds

Where,
t1 is the average time interval first measured
t2 is theaverage time interval last measured

∆t is the time between measurements (86,400 seconds = 24 hours)
13 Compute the Accumulated Time Error using the following formula:
(t1 - t2) seconds = Error (seconds)
Where t1 and t2 are defined as in the previous step.
14 Record the results of Holdover Aging and 1 PPS Accumulated Time
Error in the Test 2 row of the Performance Test Record.

Operating and Programming Guide

D-23

Appendix D Performance Tests
Complete Performance Tests

Test 3: 1 PPS Time Accuracy (Locked)
This specification is a statistical probability that the Receiver will
conform to the standard as described. This cannot be tested with any
degree of confidence except at NIST or an equivalent National
Standards Laboratory. Actual accuracy obtained depends on the exact
knowledge of the geophysical location, characteristics and delay in the
antenna, calibration of all measurement delays, and calibration of
antenna cable delay. Calibration of both ionospheric and tropospheric
delay use the standard algorithms provided in the GPS data messages.
At the 95% confidence level, time errors associated with the Receiver,
GPS system, and ionospheric and tropospheric effects will be less than
110 ns.

Test 4: 10 MHz Frequency Stability (Time Domain)
and Phase Noise (Frequency Domain) Measurements
NOTE

High accuracy precision measurements of both time and frequency
domain stability are available through the National Institute of
Standards and Technology (NIST) in the USA, and at other equivalent
National Standards Laboratories. NIST can completely characterize
and verify all major specifications of the 58503B or 59551A. For
information regarding the various tests available, contact:
National Institute of Standards and Technology,
Measurements Services Office
325 Broadway, Boulder CO 80303-3328 USA,
Telephone: (303) 497-3753

Frequency Stability (Time Domain)
This is an engineering-level measurement requiring a special test
setup. The test setup must be carefully designed to eliminate all
sources of noise. For more information on how to make this
measurement, see Application Note 358-12. Also, see NIST Technical
Note 1337 (available from US Government Printing Office,
Washington DC., USA). This is an excellent theoretical as well as
technical reference for this measurement.

Phase Noise (Frequency Domain)
This measurement requires the HP 3048A Phase Noise Measurement
System or equivalent, a highly specialized test system. In order to
perform properly, this system must contain a reference oscillator with
phase noise characteristics that are equal to or better than the 58503B
or 59551A.
This completes the performance tests.
D-24

Operating and Programming Guide

Appendix D Performance Tests
Complete Performance Tests

Operating and Programming Guide

D-25

Appendix D Performance Tests
58503B Performance Test Record

58503B Performance Test Record
Model 58503B GPS Time and Frequency Reference Receiver
Serial Number: __________________________ Repair/Work Order No. _______________________
Test Performed By:_______________________ Temperature: ________________________________
Date: ___________________________________ Relative Humidity: ___________________________
Notes: ________________________________________________________________________________
Line Number

Operational Verification

Test Results
Pass

Fail

1

10 MHz Verification

____

____

2

1 PPS Verification

____

____

3

Time of Day RS-232 Serial Interface Verification

____

____

4

Antenna Power Verification

____

____

5

Front Panel Display/Keypad Verification
(Option 001 Only)

____

____

58503B Complete Performance Tests
Test Number

Test Description

Results

Limits

1

10 MHz Frequency Accuracy

1. ______________

Better than 1 x 10−12 for a
one day average, 0° to
50° C.

and

2

1 PPS Jitter (Locked to GPS)

2. _____________

10 MHz Holdover Aging

1. ______________

and
1 PPS Accumulated Time error
(Unlocked)

2. _____________

<750 ps with at least one
satellite in view, Selective
Availability on.
<1 x 10−10/day average
frequency change in
24 hours unlocked after
3 days locked operation
for any 10° C range
between 10° C and 40° C.
<8.6 us accumulated in
24 hours unlocked after
3 days of locked operation
with a fixed antenna
location, any 10° C range
between 10° C and 40° C.

3

1 PPS Time Accuracy (Locked)

_____________

4

10 MHz Frequency Stability
(Time Domain) and Phase Noise
(Frequency Domain)
Measurement

_____________

D-26

Operating and Programming Guide

Appendix D Performance Tests
59551A Performance Test Record

59551A Performance Test Record
Model 59551A GPS Measurements Synchronization Module
Serial Number: __________________________ Repair/Work Order No. _______________________
Test Performed By:_______________________ Temperature: ________________________________
Date: ___________________________________ Relative Humidity: ___________________________
Notes: ________________________________________________________________________________
Line Number

Operational Verification

Test Results
Pass

Fail

1

10 MHz Verification

____

____

2

1 PPS Verification

____

____

3

IRIG-B Verification

____

____

4

Time of Day RS-232 Serial Interface Verification

____

____

5

Antenna Power Verification

____

____

6

Time Tagging (Stamping) Verification

____

____

7

Programmable Pulse Verification

____

____

59551A Complete Performance Tests
Test Number

Test Description

Results

Limits

1

10 MHz Frequency Accuracy

1. ______________

Better than 1 x 10−12 for a
one day average, 0° to
50° C.

and

2

1 PPS Jitter (Locked to GPS)

2. _____________

10 MHz Holdover Aging

1. ______________

and
1 PPS Accumulated Time error
(Unlocked)

2. _____________

<750 ps with at least one
satellite in view, Selective
Availability on.
<1 x 10−10/day average
frequency change in
24 hours unlocked after
3 days locked operation
for any 10° C range
between 10° C and 40° C.
<8.6 us accumulated in
24 hours unlocked after
3 days of locked operation
with a fixed antenna
location, any 10° C range
between 10° C and 40° C.

3

1 PPS Time Accuracy (Locked)

_____________

4

10 MHz Frequency Stability
(Time Domain) and Phase Noise
(Frequency Domain)
Measurement

_____________

Operating and Programming Guide

D-27

Appendix D Performance Tests
59551A Performance Test Record

D-28

Operating and Programming Guide

E

58503B Specifications

Appendix E 58503B Specifications
Specifications and Characteristics

Specifications and Characteristics
The specifications and characteristics of the 58503B GPS Time and
Frequency Reference Receiver are provided in this chapter.

GPS Receiver Features
Eight-channel, parallel tracking GPS engine
C/A Code, L1 Carrier
SmartClock™ technology
Enhanced GPS technology

E-2

Operating and Programming Guide

Appendix E 58503B Specifications
Specifications and Characteristics

10 MHz Output

Note 2

Specifications
Locked:
Frequency Accuracy: Better than
1 × 10−12, for a one-day average,
0° C to 50° C.
Unlocked:
Holdover aging:
<1 × 10−10 per day average
frequency change in 24 hours of
unlocked operation. (See Note 1.)
Phase Noise: (Locked)
Offset From
Signal (Hz)
1
10
100
1000
10000

SSB Phase
Noise (dBc)
−85
−125
−135
−140
−145

Time Domain Stability: (Locked)
(See graph on next page.)
Averaging
Time Seconds
0.01
0.1
1
10
100
1000

Root Allan
Variance
1.5 × 10−10
1.5 × 10−11
5 × 10−12
5 × 10−12
5 × 10−11
5 × 10−11

Supplemental Information
• Waveform: Sine wave
• Amplitude: >1 volt p-p into a
50Ω load
• Harmonic Distortion:
<−25 dBc (Typical)
• Non-harmonic signals:
<−60 dBc (Typical)
• Source impedance:
50Ω (nominal)
• Coupling: ac
• Connector: BNC
Note 1
This specification has a 95% probability,
and is based on the availability of four or
more GPS satellites during three days of
locked operation with a fixed antenna
location. The temperature must remain
within a 10° C range between 10° C and
40° C.

When a quartz crystal oscillator has not
been operated for a period of time, or if it
has been subjected to severe thermal or
mechanical shock, as might be
encountered during product shipment, the
oscillator may take some time to stabilize.
In most cases, the oscillator will drift and
then stabilize at or below its specified rate
within a few days after being turned on.
In isolated cases, depending upon the
amount of time the oscillator has been off
and the environmental conditions it has
experienced, the oscillator may take up to
one week to reach its specified aging rate
and to operate without significant
frequency “jumps.”
When a GPS Receiver is initially turned
on and locked to the GPS satellite
system, it will achieve GPS lock within
30 minutes of operation. It has a 95%
probability of meeting unlocked (holdover)
specifications after 24 hours of warmup,
followed by GPS lock for 48 hours. The
longer GPS Receiver (and its quartz
oscillator) operates, the better its stability
and unlocked (holdover) performance
becomes.

1 PPS Output
Specifications
Locked:
Jitter of leading edge: <750 ps
rms with at least one satellite in
view, SA on.

Additional Features
Alarm Output: TTL open collector
with internal pull-up resistor.
Circuit can sink up to 10 ma.
Provides a logic output to allow
monitoring of normal (H) and
abnormal (L) operation
externally and remotely.
BNC connector.
Front Panel Indicators (LEDs):
Power
GPS Lock
Holdover Mode
Alarm
Remote Interface:
RS-232-C DTE configuration:
Complete remote control and
interrogation of all instrument
functions and parameters.
Factory defaults: baud rate 9600,
8 data bits, 1 start bit, 1 stop bit,
no parity. Other settings are
programmable.
Connector: 25-pin female
rectangular D subminiature on
rear panel.
Time code output is available to a
computer immediately preceding
the 1 PPS signal for the current
second.

Time Accuracy:
<110 ns with respect to UTC
(USNO MC)—95% probability
when unit is properly installed,
calibrated, and locked to GPS.

Environmental
Specifications

Unlocked:
Accumulated time error: <8.6 µs
accumulated in 24 hours of
unlocked operation. (See Note 1.)

Operating: 0° C to +50° C
Storage: −40° C to +80° C

Supplemental Information
• Pulse Width: 26 µsec
• Amplitude: >2.4 volts into
50Ω load. (TTL compatible)
• Connector: BNC
• Rise time: <25 ns

Operating and Programming Guide

Time and Frequency Reference
Receiver (58503B)

Antenna (58532A)
Operating: −30° C to +80° C
Storage: −40° C to +85° C

E-3

Appendix E 58503B Specifications
Specifications and Characteristics

Power Requirements
AC Power (standard):
90 to 132 Vac or 198 to 264 Vac,
automatically selected;
50 to 60 Hz.
Option AWQ:
Unit accepts:
+24 Vdc or + 48 Vdc nominal.
Actual operating range:
+19 to +60 Vdc operating range.
Greater than
+23 Vdc required to start.
Input Power (all options):
<35 watts (nominal).

Weight and Size

10 MHz Root Allan Variance

Dimensions:
88.5 mm H ×
212.6 mm W × 348.3 mm D.
Half-Rack Module
Weight: 3.6 kg (8 lbs).

E-4

Operating and Programming Guide

Appendix E 58503B Specifications
Specifications and Characteristics

Other Information
The standard 58503B does not include a display or a keypad. While not
necessary, it may be convenient to track the Receiver’s progress during
installation and startup by monitoring the satellites being tracked,
location (position), time and other parameters. The 58503B, however,
is supplied with a small Windows 3.1 program named SatStat (5955113401), which can serve to display important parameters. SatStat
operates on any PC that can run Windows 3.1, and that has an
available serial interface.
SatStat provides several useful functions. It continuously polls the
RS-232C interface and displays Receiver information most likely to be
of interest. This includes satellites being tracked along with their
elevation and azimuth, SmartClock State (locked, holdover, etc.),
antenna coordinates, time and frequency figures of merit and other
data. In addition, a clock window is provided to display time of day in
real time. Finally, SatStat allows you to easily change many receiver
parameters, such as antenna delay, by simply picking the item from a
pop-up menu and entering a new value. With SatStat and a PC,
you can monitor and control many aspects of the Receiver status
without developing software.
Achieving accurate time of day requires care in determining cable
delays, Receiver bias, position (Lat, Lon, Alt), atmospheric conditions
and other parameters which are dependent on each individual
installation.

Options and Accessories
Available options and accessories include an antenna, an antenna
environmental cover and ground plane, pre-configured cables,
a lightning arrester, an antenna line amplifier, a built-in display and
dc power.

Operating and Programming Guide

E-5

Appendix E 58503B Specifications
Specifications and Characteristics

This page intentionally left blank.

E-6

Operating and Programming Guide

F

59551A Specifications

Appendix F 59551A Specifications
Specifications and Characteristics

Specifications and Characteristics
The specifications and characteristics of the 59551A GPS
Measurements Synchronization Module are provided in this chapter.

GPS Receiver Features
Eight-channel, parallel tracking GPS engine
C/A Code, L1 Carrier
SmartClock™ technology
Enhanced GPS technology

Operating and Programming Guide

F-2

Appendix F 59551A Specifications
Specifications and Characteristics

1 PPS Output
Specifications
Locked:
Jitter of leading edge: <750 ps
rms with at least one satellite in
view.
Time Accuracy:
<110 ns with respect to UTC
(USNO MC)—95% probability
when unit is properly installed,
calibrated, and locked to GPS.
Unlocked:
Accumulated time error: <8.6 µs
accumulated in 24 hours of
unlocked operation. (See Note 1.)
Supplemental Information
• Pulse Width: 26 µsec
• Amplitude: >2.4 volts into
50Ω load. (TTL compatible)
• Connector: BNC
• Rise time: <5 ns

Additional Features
Alarm BITE Output:
Basic unit output: solid state relay
(normally open); closed contact
indicates system fault or loss of
satellite lock. Contact rating
200 Vdc @ 0.5 amps.
Connector: Twin BNC
IRIG-B123 Output Port
BNC connector
Note 1
This specification has a 95% probability,
and is based on availability of four or more
GPS satellites during three days locked
operation with a fixed antenna location.
The temperature must remain within a
10° C range between 10° C and 40° C.

Note 2
When a quartz crystal oscillator has not
been operated for a period of time, or if it
has been subjected to severe thermal or
mechanical shock, as might be
encountered during product shipment, the
oscillator may take some time to stabilize.
In most cases, the oscillator will drift and
then stabilize at or below its specified rate
within a few days after being turned on.
In isolated cases, depending upon the

amount of time the oscillator has been off
and the environmental conditions it has
experienced, the oscillator may take up to
one week to reach its specified aging rate
and to operate without significant
frequency “jumps.”
When a GPS Receiver is initially turned
on and locked to the GPS satellite
system, it will achieve GPS lock within
30 minutes of operation. It has a 95%
probability of meeting unlocked (holdover)
specifications after 24 hours of warmup,
followed by GPS lock for 48 hours. The
longer GPS Receiver (and its quartz
oscillator) operates, the better its stability
and unlocked (holdover) performance
becomes.

Three Time-tag Inputs
Received signal: TTL, 50Ω.
Time-tag accuracy: same as the
accuracy of the 59551A.
Quantization: 100 ns
Input Interface: BNC
Minimum Pos/Neg pulse width:
200 ns
Three time-tag buffers: 256 events
each, retrievable via RS-232C.
Minimum time between events:
1 ms
Maximum stamp rate:
1 measurement per ms

Remote Interface:
(Two RS-232C Ports)
RS-232-C DTE configuration:
PRIMARY PORT
Complete remote control and
interrogation of all instrument
functions and parameters.
SECONDARY PORT
Interrogation of all instrument
functions and parameters.
Factory defaults: baud rate 9600—
8 data bits, 1 start bit, 1 stop bit,
no parity. Other settings are
programmable.
Connectors: 9-pin female
rectangular D subminiature
(DB-9) on front panel, 25-pin
female rectangular D
subminiature (DB-25) on rear
panel.
Time code output is available to a
computer immediately preceding
the 1 PPS signal for the current
second.

Timer/Clock Output
Programmable Pulse Output:
Single pulse at the time
programmed via RS-232C port,
or repetitive output pulse at a
programmable repetition period
from 1 second to 1 year.
Quantization: 100 ns
Accuracy: same as the time
accuracy of the 59551A.
Front Panel Indicators (LEDs):
Power
GPS Lock
Holdover Mode
Alarm

Operating and Programming Guide

F-3

Appendix F 59551A Specifications
Specifications and Characteristics

Environmental Specifications
Measurements Synchronization Module (59551A)
Operating: 0° C to +50° C
Storage: −40° C to +80° C
Antenna (58532A)
Operating: −40° C to +80° C
Storage: −40° C to +85° C

Power Requirements
AC Power:
90 to 132 Vac or 198 to 264 Vac, automatically selected;
50 to 60 Hz.
or
DC Power:
129 Vdc nominal (115 to 140 Vdc operating range).
Input Power (all options):
<35 watts (nominal).

Weight and Size
Dimensions:
88.5 mm H × 212.6 mm W × 348.3 mm D. Half-Rack Module
Weight: 3.6 kg (8 lbs).
Surge Withstand:
Meets IEEE/ANSI C37.90, C37.90.1

Operating and Programming Guide

F-4

Appendix F 59551A Specifications
Specifications and Characteristics

Other Information
The standard 59551A does not include a display or a keypad. While not
necessary, it may be convenient to track the Receiver’s progress during
installation and startup by monitoring the satellites being tracked,
location (position), time and other parameters. The 59551A, however,
is supplied with a small Windows 3.1 program named SatStat (5955113401), which can serve to display important parameters. SatStat
operates on any PC that can run Windows 3.1, and that has an
available serial interface.
SatStat provides several useful functions. It continuously polls the
RS-232C interface and displays Receiver information most likely to be
of interest. This includes satellites being tracked along with their
elevation and azimuth, SmartClock State (locked, holdover, etc.),
antenna coordinates, time and frequency figures of merit and other
data. In addition, a clock window is provided to display time of day in
real time. Finally, SatStat allows you to easily change many receiver
parameters, such as antenna delay, by simply picking the item from a
pop-up menu and entering a new value. With SatStat and a PC,
you can monitor and control many aspects of the Receiver status
without developing software.
Achieving accurate time of day requires care in determining cable
delays, Receiver bias, position (Lat, Lon, Alt), atmospheric conditions
and other parameters which are dependent on each individual
installation.

Options and Accessories
Available options and accessories include an antenna, an antenna
environmental cover and ground plane, pre-configured cables,
a lightning arrester, an antenna line amplifier, a built-in display and
ac power.

F-5

Operating and Programming Guide

Appendix F 59551A Specifications
Specifications and Characteristics

This page intentionally left blank.

Operating and Programming Guide

F-6

Command Index
*CLS, 5-54, 5-115
*ESE, 5-66
*ESE?, 5-67
*ESR?, 5-67
*IDN?, 5-114
*SRE, 5-57
*SRE?, 5-57
*STB?, 5-58
*TST?, 5-70
:DIAGnostic:DOWNload, 5-115
:DIAGnostic:ERASe, 5-115
:DIAGnostic:ERASe?, 5-116
:DIAGnostic:LIFetime:COUNt?, 5-71
:DIAGnostic:LOG:CLEar, 5-45
:DIAGnostic:LOG:CLEar , 5-45
:DIAGnostic:LOG:COUNt?, 5-46
:DIAGnostic:LOG:READ:ALL?, 5-45
:DIAGnostic:LOG:READ?, 5-46
:DIAGnostic:LOG:READ? , 5-47
:DIAGnostic:QUERy:RESPonse?, 5-108
:DIAGnostic:ROSCillator:EFControl:RELative?, 5-28
:DIAGnostic:TEST:RESult?, 5-72
:DIAGnostic:TEST?, 5-71
:FORMat:DATA, 5-93
:FORMat:DATA?, 5-93
:GPS:INITial:DATE, 5-9
:GPS:INITial:POSition, 5-10
:GPS:INITial:TIME, 5-11
:GPS:POSition, 5-12
:GPS:POSition:ACTual?, 5-14
:GPS:POSition:HOLD:LAST?, 5-14
:GPS:POSition:HOLD:STATe?, 5-15
:GPS:POSition:SURVey:PROGress?, 5-15
:GPS:POSition:SURVey:STATe, 5-15
:GPS:POSition:SURVey:STATe:POWerup, 5-16
:GPS:POSition:SURVey:STATe:POWerup?, 5-16
:GPS:POSition:SURVey:STATe?, 5-16
:GPS:POSition?, 5-13
:GPS:REFerence:ADELay, 5-22
:GPS:REFerence:ADELay?, 5-23

Operating and Programming Guide

Command Index-1

Command Index

:GPS:REFerence:VALid?, 5-24
:GPS:SATellite:TRACking:COUNt?, 5-25
:GPS:SATellite:TRACking:EMANgle, 5-17
:GPS:SATellite:TRACking:EMANgle?, 5-17
:GPS:SATellite:TRACking:IGNore, 5-18
:GPS:SATellite:TRACking:IGNore:ALL, 5-18
:GPS:SATellite:TRACking:IGNore:COUNt?, 5-20
:GPS:SATellite:TRACking:IGNore:NONE, 5-18
:GPS:SATellite:TRACking:IGNore:STATe?, 5-21
:GPS:SATellite:TRACking:IGNore?, 5-18
:GPS:SATellite:TRACking:INCLude, 5-19
:GPS:SATellite:TRACking:INCLude:ALL, 5-19
:GPS:SATellite:TRACking:INClude:COUNt?, 5-20
:GPS:SATellite:TRACking:INCLude:NONE, 5-19
:GPS:SATellite:TRACking:INClude:STATe?, 5-21
:GPS:SATellite:TRACking:INCLude?, 5-19
:GPS:SATellite:TRACking?, 5-24
:GPS:SATellite:VISible:PREDicted:COUNt?, 5-26
:GPS:SATellite:VISible:PREDicted?, 5-25
:LED:ALARm?, 5-56
:LED:GPSLock?, 5-29
:LED:HOLDover?, 5-29
:PTIMe:DATE?, 5-75
:PTIMe:LEAPsecond:ACCumulated?, 5-79
:PTIMe:LEAPsecond:DATE?, 5-80
:PTIMe:LEAPsecond:DURation?, 5-81
:PTIMe:LEAPsecond:STATe?, 5-82
:PTIMe:PPS:EDGE, 5-78
:PTIMe:PPS:EDGE?, 5-78
:PTIMe:TIME:STRing?, 5-76
:PTIMe:TIME?, 5-75
:PTIMe:TZONe, 5-77
:PTIMe:TZONe?, 5-77
:PULSe:CONTinuous:PERiod, 5-84
:PULSe:CONTinuous:PERiod?, 5-84
:PULSe:CONTinuous:STATe, 5-85
:PULSe:CONTinuous:STATe?, 5-85
:PULSe:REFerence:EDGE, 5-86
:PULSe:REFerence:EDGE?, 5-86
:PULSe:STARt:DATE, 5-87
:PULSe:STARt:DATE?, 5-87
:PULSe:STARt:TIME, 5-88
:PULSe:STARt:TIME?, 5-88

Command Index-2

Operating and Programming Guide

Command Index

:SENSe:DATA:CLEar, 5-90
:SENSe:DATA:CLEar , 5-91
:SENSe:DATA:MEMory:OVERflow:COUNt?, 5-97
:SENSe:DATA:MEMory:OVERflow:COUNt? , 5-98
:SENSe:DATA:MEMory:SAVE, 5-98
:SENSe:DATA:MEMory:SAVE?, 5-99
:SENSe:DATA:POINts?, 5-94
:SENSe:DATA:POINts? , 5-94
:SENSe:DATA:TSTamp?, 5-95
:SENSe:DATA?, 5-92
:SENSe:TSTamp :EDGE, 5-90
:SENSe:TSTamp :EDGE?, 5-90
:STATus::CONDition?, 5-60
:STATus::ENABle, 5-62
:STATus::ENABle?, 5-63
:STATus::EVENt?, 5-61
:STATus::NTRansition, 5-64
:STATus::NTRansition?, 5-65
:STATus::PTRansition, 5-64
:STATus::PTRansition?, 5-65
:STATus:PRESet:ALARm, 5-55
:STATus:QUEStionable:CONDition:USER, 5-68
:STATus:QUEStionable:EVENt:USER, 5-69
:SYNChronization:FFOMerit?, 5-30
:SYNChronization:HOLDover:DURation:THReshold, 5-34
:SYNChronization:HOLDover:DURation:THReshold:EXCeeded?, 5-35
:SYNChronization:HOLDover:DURation:THReshold?, 5-34
:SYNChronization:HOLDover:DURation?, 5-33
:SYNChronization:HOLDover:INITiate, 5-36
:SYNChronization:HOLDover:RECovery:INITiate, 5-37
:SYNChronization:HOLDover:RECovery:LIMit:IGNore, 5-38
:SYNChronization:HOLDover:TUNCertainty:PREDicted?, 5-31
:SYNChronization:HOLDover:TUNCertainty:PRESent?, 5-31
:SYNChronization:HOLDover:WAITing?, 5-37
:SYNChronization:IMMediate, 5-38
:SYNChronization:STATe?, 5-28
:SYNChronization:TFOMerit?, 5-32
:SYNChronization:TINTerval?, 5-32

Operating and Programming Guide

Command Index-3

Command Index

:SYSTem:COMMunicate::BAUD, 5-101
:SYSTem:COMMunicate::BAUD?, 5-102
:SYSTem:COMMunicate::BITS?, 5-103
:SYSTem:COMMunicate::FDUPlex, 5-103
:SYSTem:COMMunicate::FDUPlex?, 5-104
:SYSTem:COMMunicate::PACE, 5-104
:SYSTem:COMMunicate::PACE?, 5-105
:SYSTem:COMMunicate::PARity, 5-105
:SYSTem:COMMunicate::PARity?, 5-106
:SYSTem:COMMunicate::PRESet, 5-110
:SYSTem:COMMunicate::SBITs?, 5-107
:SYSTem:COMMunicate:SERial1:BITS, 5-102
:SYSTem:COMMunicate:SERial1:SBITs, 5-106
:SYSTem:COMMunicate?, 5-101
:SYSTem:DATE?, 5-75
:SYSTem:ERRor?, 5-42, 5-116
:SYSTem:LANGuage?, 5-118
:SYSTem:PRESet, 5-110
:SYSTem:STATus:LENGth?, 5-41
:SYSTem:STATus?, 5-41
:SYSTem:TIME?, 5-75

Command Index-4

Operating and Programming Guide

General Index
SYMBOLS
*CLS, 5-54, 5-115
*ESE, 5-66
*ESE?, 5-67
*ESR?, 5-67
*IDN?, 5-114
*SRE, 5-57
*SRE?, 5-57
*STB?, 5-58
*TST?, 5-70
:DIAGnostic:DOWNload, 5-115
:DIAGnostic:ERASe, 5-115
:DIAGnostic:ERASe?, 5-116
:DIAGnostic:LIFetime:COUNt?, 5-71
:DIAGnostic:LOG:CLEar, 5-45
:DIAGnostic:LOG:CLEar , 5-45
:DIAGnostic:LOG:COUNt?, 5-46
:DIAGnostic:LOG:READ:ALL?, 5-45
:DIAGnostic:LOG:READ?, 5-46
:DIAGnostic:LOG:READ? , 5-47
:DIAGnostic:QUERy:RESPonse?, 5-108
:DIAGnostic:ROSCillator:EFControl:REL
ative?, 5-28
:DIAGnostic:TEST:RESult?, 5-72
:DIAGnostic:TEST?, 5-71
:FORMat:DATA, 5-93
:FORMat:DATA?, 5-93
:GPS:INITial:DATE, 5-9
:GPS:INITial:POSition, 5-10
:GPS:INITial:TIME, 5-11
:GPS:POSition, 5-12
:GPS:POSition:ACTual?, 5-14
:GPS:POSition:HOLD:LAST?, 5-14
:GPS:POSition:HOLD:STATe?, 5-15
:GPS:POSition:SURVey:PROGress?, 5-15
:GPS:POSition:SURVey:STATe, 5-15
:GPS:POSition:SURVey:STATe:POWerup
, 5-16
:GPS:POSition:SURVey:STATe:POWerup
?, 5-16
:GPS:POSition:SURVey:STATe?, 5-16
:GPS:POSition?, 5-13
:GPS:REFerence:ADELay, 5-22
:GPS:REFerence:ADELay?, 5-23
:GPS:REFerence:VALid?, 5-24
:GPS:SATellite:TRACking:COUNt?, 5-25
:GPS:SATellite:TRACking:EMANgle,
5-17
:GPS:SATellite:TRACking:EMANgle?,
5-17
:GPS:SATellite:TRACking:IGNore, 5-18

Operating and Programming Guide

:GPS:SATellite:TRACking:IGNore:ALL,
5-18
:GPS:SATellite:TRACking:IGNore:
COUNt?, 5-20
:GPS:SATellite:TRACking:IGNore:NONE
, 5-18
:GPS:SATellite:TRACking:IGNore:
STATe?, 5-21
:GPS:SATellite:TRACking:IGNore?, 5-18
:GPS:SATellite:TRACking:INCLude,
5-19
:GPS:SATellite:TRACking:INCLude:ALL,
5-19
:GPS:SATellite:TRACking:INClude:
COUNt?, 5-20
:GPS:SATellite:TRACking:INCLude:
NONE, 5-19
:GPS:SATellite:TRACking:INClude:
STATe?, 5-21
:GPS:SATellite:TRACking:INCLude?,
5-19
:GPS:SATellite:TRACking?, 5-24
:GPS:SATellite:VISible:PREDicted:
COUNt?, 5-26
:GPS:SATellite:VISible:PREDicted?, 5-25
:LED:ALARm?, 5-56
:LED:GPSLock?, 5-29
:LED:HOLDover?, 5-29
:PTIMe:DATE?, 5-75
:PTIMe:LEAPsecond:ACCumulated?,
5-79
:PTIMe:LEAPsecond:DATE?, 5-80
:PTIMe:LEAPsecond:DURation?, 5-81
:PTIMe:LEAPsecond:STATe?, 5-82
:PTIMe:PPS:EDGE, 5-78
:PTIMe:PPS:EDGE?, 5-78
:PTIMe:TIME:STRing?, 5-76
:PTIMe:TIME?, 5-75
:PTIMe:TZONe, 5-77
:PTIMe:TZONe?, 5-77
:PULSe:CONTinuous:PERiod, 5-84
:PULSe:CONTinuous:PERiod?, 5-84
:PULSe:CONTinuous:STATe, 5-85
:PULSe:CONTinuous:STATe?, 5-85
:PULSe:REFerence:EDGE, 5-86
:PULSe:REFerence:EDGE?, 5-86
:PULSe:STARt:DATE, 5-87
:PULSe:STARt:DATE?, 5-87
:PULSe:STARt:TIME, 5-88
:PULSe:STARt:TIME?, 5-88
:SENSe:DATA:CLEar, 5-90
:SENSe:DATA:CLEar , 5-91

General Index-1

General Index

:SENSe:DATA:MEMory:OVERflow:COU
Nt?, 5-97
:SENSe:DATA:MEMory:OVERflow:COU
Nt? , 5-98
:SENSe:DATA:MEMory:SAVE, 5-98
:SENSe:DATA:MEMory:SAVE?, 5-99
:SENSe:DATA:POINts?, 5-94
:SENSe:DATA:POINts? , 5-94
:SENSe:DATA:TSTamp?, 5-95
:SENSe:DATA?, 5-92
:SENSe:TSTamp :EDGE, 5-90
:SENSe:TSTamp :EDGE?, 5-90
:STATus::CONDition?, 5-60
:STATus::ENABle, 5-62
:STATus::ENABle?, 5-63
:STATus::EVENt?, 5-61
:STATus::NTRansition, 5-64
:STATus::NTRansition?, 5-65
:STATus::PTRansition, 5-64
:STATus::PTRansition?, 5-65
:STATus:PRESet:ALARm, 5-55
:STATus:QUEStionable:CONDition:
USER, 5-68
:STATus:QUEStionable:EVENt:USER,
5-69
:SYNChronization:FFOMerit?, 5-30
:SYNChronization:HOLDover:DURation:
THReshold, 5-34
:SYNChronization:HOLDover:DURation:
THReshold:EXCeeded?, 5-35
:SYNChronization:HOLDover:DURation:
THReshold?, 5-34
:SYNChronization:HOLDover:DURation?
, 5-33
:SYNChronization:HOLDover:INITiate,
5-36
:SYNChronization:HOLDover:RECovery:
INITiate, 5-37
:SYNChronization:HOLDover:RECovery:
LIMit:IGNore, 5-38
:SYNChronization:HOLDover:TUNCertai
nty:PREDicted?, 5-31
:SYNChronization:HOLDover:TUNCertai
nty:PRESent?, 5-31
:SYNChronization:HOLDover:WAITing?,
5-37
:SYNChronization:IMMediate, 5-38
:SYNChronization:STATe?, 5-28
:SYNChronization:TFOMerit?, 5-32
:SYNChronization:TINTerval?, 5-32
:SYSTem:COMMunicate::BAUD,
5-101
:SYSTem:COMMunicate::BAUD?,
5-102
:SYSTem:COMMunicate::BITS?,
5-103

General Index-2

:SYSTem:COMMunicate::FDUPlex
, 5-103
:SYSTem:COMMunicate::FDUPlex
?, 5-104
:SYSTem:COMMunicate::PACE,
5-104
:SYSTem:COMMunicate::PACE?,
5-105
:SYSTem:COMMunicate::PARity,
5-105
:SYSTem:COMMunicate::PARity?,
5-106
:SYSTem:COMMunicate::PRESet,
5-110
:SYSTem:COMMunicate::SBITs?,
5-107
:SYSTem:COMMunicate:SERial1:BITS,
5-102
:SYSTem:COMMunicate:SERial1:SBITs,
5-106
:SYSTem:COMMunicate?, 5-101
:SYSTem:DATE?, 5-75
:SYSTem:ERRor?, 5-42, 5-116
:SYSTem:LANGuage?, 5-118
:SYSTem:PRESet, 5-110
:SYSTem:STATus:LENGth?, 5-41
:SYSTem:STATus?, 5-41
:SYSTem:TIME?, 5-75

NUMERICS
1 PPS, 1-4
1 PPS error estimation, 5-31
1 PPS output, 5-27
1 PPS output quality, 4-7, 4-10, 5-27,
5-28, 5-29, 5-30, 5-31, 5-32, 5-33, 5-34,
5-35
1 PPS polarity, 4-10, 5-78
1 PPS reference edge, 4-10
1 PPS reference synchronization, 4-7
1 PPS output, 1-6
1 PP2S connector (optional), 1-4
1 PP2S output, 1-4
1 PPS signal is locked to valid GPS
reference, 5-24
1 PPS signal is valid, 5-24
10 MHz OUT, 1-4
10 MHz output, 5-27
10 MHz output quality, 4-7, 4-10, 5-27,
5-28, 5-29, 5-30, 5-31, 5-32, 5-33, 5-34,
5-35

A
abbreviated commands, B-5
ac power, 1-6
ACQUISITION, 3-11, 3-14
acquisition of satellites, 4-5, 4-6, 5-7, 5-8
Alarm, 1-2, 1-4

Operating and Programming Guide

General Index

alarm analysis, 4-8, 5-39, 5-40, 5-48, 5-49,
5-50, 5-51, 5-52, 5-53, 5-54, 5-55, 5-56,
5-57, 5-58, 5-59, 5-60, 5-61, 5-62, 5-63,
5-64, 5-65, 5-66, 5-67, 5-68, 5-69
Alarm BITE, 1-6
alarm BITE, 4-8, 5-39, 5-48, 5-49, 5-50,
5-51, 5-52, 5-53, 5-54, 5-56, 5-57, 5-58,
5-59, 5-60, 5-61, 5-62, 5-63, 5-64, 5-65,
5-66, 5-67, 5-68, 5-69
alarm clear, 4-8, 5-39, 5-54, 5-55, 5-56,
5-57, 5-58
Alarm condition, 1-2, 1-4, 1-5
Alarm indicator, 1-6, 4-8, 5-39, 5-56
Alarm LED, 1-3
alarm relay, 4-8, 5-39, 5-48, 5-49, 5-50,
5-51, 5-52, 5-53, 5-54, 5-55, 5-56, 5-57,
5-58, 5-59, 5-60, 5-61, 5-62, 5-63, 5-64,
5-65, 5-66, 5-67, 5-68, 5-69
alarm setup, 4-8, 5-39, 5-48, 5-49, 5-50,
5-51, 5-52, 5-53, 5-54, 5-56, 5-57, 5-58,
5-59, 5-60, 5-61, 5-62, 5-63, 5-64, 5-65,
5-66, 5-67, 5-68, 5-69
alarm status, 5-50
alarm test, 4-8, 5-39, 5-40, 5-68, 5-69,
5-70, 5-71, 5-72
antenna
delay values, 5-22
antenna connection, 5-22
ANTENNA connector, 1-4, 1-6
antenna delay, 3-17
antenna delay compensation, 4-6, 5-8
antenna placement, 4-6, 5-8, 5-22
ASCII Data, B-11
azimuth angle, 3-15

B
baud, 2-9, 5-101, 5-102, 5-110
baud rate, 2-9
BINARY Data, 5-93, B-11
Boolean, B-5

C
C/N, 3-15
cable delay compensation, 4-6, 5-8
cables, 5-22
crossover, 2-5
HP 24542G interface, 2-6
HP 24542U, 2-8
HP 40242M interface, 2-6
modem-eliminator, 2-5
null-modem, 2-5
carrier-to-noise ratio, 3-15
characteristics
58503B, E-2
59551A, F-2
clear, 5-90, 5-91
alarm, 4-8, 5-39, 5-54

Operating and Programming Guide

errors, 4-8, 5-39, 5-42, 5-115
clear time stamp memory, 5-89
comma, B-4, B-6, B-9
command
abbreviated, B-5
common, B-3
format, 5-5
parameter, B-5
SCPI, B-3
syntax, B-2, B-5
terminator, B-7
terminators, B-4
command error, 4-9, 5-40, 5-48, 5-53
Command Error status, 5-48
command syntax conventions, 4-4, 5-4
commands
introduction, 4-4
Commands at a Glance, 4-16, 4-17
commands summary, 4-16, 4-17
common command
syntax, B-4
Common Command Format, B-3
common commands
description, B-3
communication
serial interface port, 2-3, 2-4, 5-100,
5-101, 5-103, 5-104, 5-105, 5-106
compensating for antenna delay, 5-22
configuration
PORT 1, 2-11, 5-100
PORT 2, 2-11, 5-100
configuration factory-default
values, 5-110
configuring PORT 1, 2-10, 4-13
configuring PORT 2, 2-10, 4-13
configuring serial interface port(s), 5-100
configuring the RS-232C ports, 2-9
conformance Information
SCPI, 4-4
connecting a computer, 2-5
connecting a laptop, 2-6
connecting a modem, 2-5, 2-6
connecting a PC, 2-6
connecting antenna system, 4-6, 5-8, 5-22
conventions
command syntax, 4-4, 5-4
Coordinated Universal Time, 5-7
CPU, 5-70
crossover cable, 2-5
current time, 4-10

D
d.dEe, B-10
d.dEe, ..., B-10
d.dEed.dEe, B-10
data, 5-92

General Index-3

General Index

data bits, 2-9, 5-102, 5-103, 5-110
date and time outputs, 4-6, 4-10, 5-8
DB-25 connector, 2-5
DB-9 connector, 2-5
dc power, 1-6
DCE, 2-5
dd, ..., B-10
dddd, B-10
decimal point, B-5, B-10
defaults, factory settings, 2-9, 4-14, 5-110,
5-111
delay value, 5-22
delay values, 5-22
delay values, antenna cables, 4-6, 5-8
diagnostic log, 4-8, 5-39, 5-43, 5-44, 5-45,
5-46, 5-47
diagnostic log messages, 5-43
diagnostic tests, 4-9, 5-40, 5-70, 5-71, 5-72
result, 5-72
diagnostics
internal self-test, 5-70
documents
list, B-12
related, B-12
download, 5-115
downloading
Using SatStat, C-2
downloading new firmware, C-2
DTE, 2-5
duplex state, 5-103, 5-104

E
echoing of the characters you type, 5-103,
5-104, 5-110
EEPROM, 5-70, 5-115
elevation angle, 3-15
elevation mask angle, 3-15
EPROM, 5-70
erasing
EEPROM, 5-116
error
hardware/firmware, A-5
query, A-5
semantic, A-5
syntactic, A-4
error analysis, 4-8, 5-39, 5-40, 5-42, 5-116
error behavior, A-6
error log, 4-8, 5-39, 5-40, 5-42, 5-116
error messages, 4-8, 5-39, A-7
error queue, 4-8, 5-39, 5-42, 5-116, A-3
error recovery, serial port, 4-8, 4-13, 5-39,
5-108
error types, A-4
error, command, 5-48, 5-53
error, reading, A-2

General Index-4

F
factory default settings, 2-9, 4-14, 5-109,
5-110
failure protection, satellite loss, 4-7, 5-27,
5-33, 5-34, 5-35
FFOM, 4-7, 5-30
FFOM value, 3-14
Figure
command list, 4-16, 4-17
factory instrument settings, 5-111
factory serial port settings, 5-111
status reporting system, 5-49
figure of merit, 5-30, 5-32, 5-74
firmware error, A-5
firmware installation, 2-3, 4-15, 5-113,
5-115, 5-116, 5-117, 5-118
firmware revision code, 2-3, 4-15, 5-114
firmware upgrade, 2-3, 5-115
flash EEPROM, 5-115
flow control state, 5-104, 5-105
format
ASCii, 5-93
INTeger, 5-93
FPGA logic, 5-70
front panel
59551A, 1-5
PORT 2, 2-4
full duplex, 2-9, 5-104, 5-110

G
GPS engine, 5-70
GPS Lock, 1-2
GPS lock, 4-5, 4-6, 5-7, 5-33, 5-34, 5-35
GPS Lock indicator, 4-7, 5-29
GPS Lock LED, 1-3, 1-5
GPS position, 4-5, 5-7, 5-13, 5-14, 5-15
GPS satellite acquisition, 4-5, 4-6, 5-7,
5-33, 5-34, 5-35
GPS time, 3-16
GPS timeline, 5-73

H
Hardware status, 5-48, 5-51, 5-60, 5-61,
5-62, 5-63, 5-64, 5-65
hardware/firmware error, A-5
HEALTH MONITOR, 3-11
health monitor screen, 3-11
Hold position mode, 3-17
Holdover, 1-2, 3-12
holdover
process, 5-27
recovery, 5-27, 5-37
status, 5-48, 5-52
tutorial, 3-8
Holdover indicator, 4-7, 5-29
Holdover LED, 1-3, 1-5
holdover loss of satellites, 4-7

Operating and Programming Guide

General Index

holdover mode, 1-2, 1-5
holdover operation, 3-8
holdover recovery, 4-7, 5-37
holdover status, 4-9
holdover threshold, 3-14
How to use the Status Screen, 3-3
58518A/519A cable, 5-22
58518AA/519AA cable, 5-22
58520A/521A cable, 5-23
58520AA/521AA cable, 5-23
59551A Receiver, 1-6
SatStat, 3-3, C-2
SmartClock, 3-11
HP 24542G interface cable, 2-6
HP 24542U cable, 2-8
HP 40242M interface cable, 2-6

I
I/O
PORT 1, 59551A, 1-6
PORT 2, 59551A, 1-5
I/O PORT 1, 4-13
identification of Receiver, 4-15, 5-114
IEEE Standard 488.2
obtaining copy of standard, B-12
IEEE 488.2
description, B-3
syntax, B-4
In This Guide, 1-ix
indicator
Alarm, 1-2, 1-5, 1-6
GPS Lock, 1-2, 1-5
Holdover, 1-2, 1-5
Power, 1-2, 1-5
indicators
Alarm, 1-3
GPS Lock, 1-3
Holdover, 1-3
Power, 1-3
initialization, 5-109
initializing the Receiver, 4-14
initiating manual Holdover, 5-27, 5-36
input
antenna, 1-6, 4-6, 5-8, 5-22
Power, 1-4
Time Tag, 1-6, 4-12
input jack, 1-6
inputs
Time tag, 1-6
install
firmware, 2-3, 4-15, 5-113, 5-115
Receiver, 5-9, 5-17, 5-22
install firmware, 5-115
INSTALL language, 5-115, 5-117
installation, 4-15

Operating and Programming Guide

interface RS-232C, 2-3
internal reference oscillator, 5-7, 5-27
internal self-test diagnostics, 5-70
interpolators, 5-70
introduction commands, 4-4
IRIG-B output, 1-6

K
keyword
separator, B-5

L
latitude, 4-5, 5-7, 5-12, 5-13, 5-14
leap second, 4-10
leap second status, 5-73
LED
Alarm, 1-2, 1-3, 1-5, 1-6, 4-8, 5-39
GPS Lock, 1-2, 1-3, 1-5, 4-7
Holdover, 1-3, 1-5, 4-7
Power, 1-2, 1-3, 1-5
lifetime count, 5-71
list of
commands, 4-16, 4-17
configuration factory-default
values, 5-110
error messages, A-7
error types, A-4
factory-default values, 5-110
response format, B-10
system preset, 5-111
literal, B-5
local time, 4-10
local time zone, 3-16
locking to GPS satellites, 4-5, 4-6, 5-7,
5-8, 5-9, 5-10, 5-11, 5-12, 5-13, 5-14, 5-15,
5-16, 5-17, 5-18, 5-19, 5-20, 5-21, 5-22,
5-23, 5-24, 5-25, 5-26, 5-33, 5-34, 5-35,
5-36, 5-37, 5-38, 5-39
log, diagnostic, 4-8, 5-39, 5-43, 5-44, 5-45,
5-46, 5-47
log, error, 4-8, 5-39, 5-40, 5-42, 5-116
longitude, 4-5, 5-7, 5-12, 5-13, 5-14

M
MAXimum, B-6
memory overflow, 4-12, 5-89
messages
program, B-7
response, B-9
messages, error, A-7
MINimum, B-6
modem-eliminator cable, 2-5
multipliers, B-7

N
new line, B-11
not tracking., 3-14

General Index-5

General Index

NRf, B-5
null-modem cable, 2-5

O
OHM, B-6
Operation status, 5-39, 5-48, 5-50, 5-60,
5-61, 5-62, 5-63, 5-64, 5-65
operational verification, D-2
output
1 PPS, 1-4, 1-6, 4-7, 4-10, 5-27, 5-28,
5-29, 5-30, 5-31, 5-32, 5-33, 5-34, 5-35,
5-78
10 MHz, 4-7, 4-10, 5-27, 5-28, 5-29,
5-30, 5-31, 5-32, 5-33, 5-34, 5-35
10 MHz OUT, 1-4
Alarm, 1-4
alarm, 4-7
Alarm BITE, 1-6
IRIG-B, 1-6
Programmable Pulse, 1-6, 4-11, 5-83,
5-84, 5-85, 5-86, 5-87, 5-88
synchronization, 5-28, 5-29, 5-30, 5-31,
5-32, 5-33, 5-34, 5-35
output pulse, 4-11, 5-83, 5-84, 5-85, 5-86,
5-87, 5-88
output synchronization, 4-7
outputs
1 PP2S (optional), 1-4
1 PPS, 1-6
IRIG-B, 1-6
Programmable Pulse, 1-6

P
pace, 2-9, 5-104, 5-105, 5-110
pacing, 5-110
parameter separator, B-6
parameter types, B-5
Boolean, B-5
literal, B-5
string, B-5
parity, 2-9, 5-105, 5-106, 5-110
performance tests, D-2
pin assignment
PORT 1, 2-3
PORT 2, 2-4
polarity of edges
1 PPS, 4-10, 5-78
programmable pulse, 4-11
time stamp, 4-12, 5-89, 5-90
PORT, 1-6
PORT 1, 2-6, 4-13, 5-100, 5-101, 5-102,
5-103, 5-104, 5-105, 5-106, 5-107, 5-110
factory-default values, 2-9
PORT 1 configuration, 2-11
PORT 1 rear panel, 2-3
PORT 1, 58503B, 1-4

General Index-6

PORT 2, 1-5, 4-13, 5-100, 5-101, 5-102,
5-103, 5-104, 5-105, 5-106, 5-107, 5-110
factory-default values, 2-9
PORT 2 configuration, 2-11
PORT 2 front panel, 2-4
Position, 3-17
position, 4-5, 5-7, 5-12, 5-13, 5-14, 5-15
position at powerup, 5-16
position hold, 5-15
Power, 1-2
power
ac, 1-6
dc, 1-6
POWER input, 1-4
power input jack, 1-6
Power input jack, 58503A, 1-4
Power LED, 1-3, 1-5
power outages, 5-89
power supply, 1-6
Power supply levels, 5-70
power surges, 5-89
Powerup status, 5-48, 5-52
predicted visible satellites, 5-25
preface, 1-ix
preset, 5-109
preset to factory defaults, 2-9, 4-14, 5-109,
5-110
product identification, 4-15, 5-114
program messages
definition, B-7
syntax, B-7
programmable pulse, 4-11, 5-83, 5-84,
5-85, 5-86, 5-87, 5-88
Programmable Pulse output, 1-6
pseudorandom noise, 3-15
pulse generator, 4-11, 5-83, 5-84, 5-85,
5-86, 5-87, 5-88
pulse output, 4-11, 5-83, 5-84, 5-85, 5-86,
5-87, 5-88

Q
QSPI, 5-70
quality
FFOM, 3-14
signal, 3-13, 3-14
TFOM, 3-13
query, B-6, B-9
query error, A-5
query parameters
, B-6
MAXimum, B-6
MINimum, B-6
querying instrument identification, 5-113
Questionable status, 5-48, 5-52
queue overflows, A-3
queue, error, 4-8, 5-39, 5-116

Operating and Programming Guide

General Index

quick reference
command list, 4-16, 4-17
factory instrument settings, 5-111
factory serial port settings, 5-110
status reporting system, 4-18

R
RAM, 5-70
rear panel
58503A, 1-4
59551A, 1-6
PORT 1, 2-3
Receiver Commands at a Glance, 4-16,
4-17
Receiver identification, 4-15, 5-113, 5-114
Receiver initialization, 4-14
Receiver Status Screen, 3-3
Receiver status screen, 5-41
recovering from holdover, 4-7, 5-27, 5-37
recovering the last query response, 4-13,
5-100
Recovery, 3-12
Reference oscillator, 5-70
related ocumentation, B-12
relay, alarm, 4-8, 5-39, 5-48, 5-49, 5-50,
5-51, 5-52, 5-53, 5-54, 5-55, 5-56, 5-57,
5-58, 5-59, 5-60, 5-61, 5-62, 5-63, 5-64,
5-65, 5-66, 5-67, 5-68, 5-69
removes error from error queue, 5-116
reset to factory defaults, 2-9, 4-14, 5-109,
5-110
response message syntax, B-9
response messages, B-9
data types, B-10
restore to factory defaults, 2-9, 4-14,
5-109, 5-110
revision code, 4-15, 5-114
RS-232C, 1-4, 1-5, 1-6
RS-232C interface, 4-13, 5-100, 5-101,
5-102, 5-103, 5-104, 5-105, 5-106, 5-107
RS-232C ports, 2-3

S
satellite acquisition, 4-5, 4-6, 5-7, 5-33,
5-34, 5-35
satellite failure protection, 4-7, 5-27, 5-33,
5-34, 5-35
satellite loss, 4-7, 5-33, 5-34, 5-35
satellite management, 4-5, 4-6, 5-7, 5-9,
5-10, 5-11, 5-12, 5-13, 5-14, 5-15, 5-16,
5-17, 5-18, 5-19, 5-20, 5-21, 5-22, 5-23,
5-24, 5-25, 5-26, 5-33, 5-34, 5-35, 5-36,
5-37, 5-38, 5-39
satellite reacquisition, 4-7
satellite selection, 4-6, 5-7
Satellite Status, 3-14

Operating and Programming Guide

satellite tracking at installation, 4-5, 5-7,
5-9
SCPI, B-2
description, B-3
version, 4-4
SCPI Command and Query Format, B-3
SCPI conformance Information, 4-4
SCPI standard, B-12
Self Test, 3-18
self test, 4-9, 5-40, 5-70, 5-71, 5-72
semantic error, A-5
separator
keyword, B-5
parameter, B-6
serial interface, 1-4, 1-5, 1-6
serial interface communication, 4-13
serial interface port, 2-3, 2-4
preset, 5-109
serial number, 5-114
serial port error recovery, 4-8, 4-13, 5-39,
5-108
serial port I/O, 4-13, 5-110
serial port settings, 2-11
setting up the Receiver, 4-15, 5-9, 5-17
settings, serial port, 2-11
signal
quality, 3-13, 3-14
signal loss, 4-7, 5-27, 5-33, 5-34, 5-35,
5-36, 5-37, 5-38
signal strength, 3-15
SmartClock Mode, 3-12
SmartClock PLL, 3-14
software pacing, 2-9
specifications
58503B, E-2
59551A, F-2
SS, 3-15
status
alarm, 5-50, 5-56
command error, 5-53, 5-66
hardware, 5-51, 5-60, 5-61, 5-62, 5-63,
5-64, 5-65
holdover, 5-52, 5-60, 5-61, 5-62, 5-63,
5-64, 5-65
operation, 5-50, 5-60, 5-61, 5-62, 5-63,
5-64, 5-65
powerup, 5-52, 5-60, 5-61, 5-62, 5-63,
5-64, 5-65
questionable, 5-52, 5-60, 5-61, 5-62,
5-63, 5-64, 5-65, 5-68
status information, 5-39
status registers, 5-48
status reporting, 4-8, 4-9, 5-39, 5-40, 5-48,
5-49, 5-50, 5-51, 5-52, 5-53, 5-54, 5-56,
5-57, 5-58, 5-59, 5-60, 5-61, 5-62, 5-63,
5-64, 5-65, 5-66, 5-67, 5-68, 5-69

General Index-7

General Index

status reporting system, 5-48
Status Reporting System Diagram, 5-49
status screen, 4-8, 5-41
status/alarm reporting system, 5-48
stop bits, 2-9, 5-106, 5-107, 5-110
strength of the signal, 3-15
string, B-5
subsystem command
syntax, B-4
suffix
elements, B-6
multipliers, B-7
suffix, multiplier, B-7
suffixes, B-6
summary
commands, 4-16, 4-17
survey mode, 5-15
Survey position mode, 3-17
SYNCHRONIZATION, 3-11
synchronization of output signals, 4-7,
5-28, 5-29, 5-30, 5-31, 5-32, 5-33, 5-34,
5-35
synchronizing to reference, 4-7, 5-27
syntactic error, A-4
syntax, 4-4, 5-4
program messages, B-7
response messages, B-9
syntax, SCPI, B-2
SYSTEM
STATUS? query, 3-3
system preset, 5-111
system time, 4-10, 5-73

time tag, 4-12, 5-89, 5-90, 5-91, 5-92, 5-93,
5-94, 5-95, 5-96, 5-97, 5-98, 5-99
Time Tag inputs, 4-12
Time tag inputs, 1-6
time transfer information, 5-7
time zone setting, 4-10, 5-73, 5-77
Time-stamped Edge, 4-12, 5-90
time-stamped edge, 5-90
timing outputs, 4-7, 5-28, 5-29, 5-30, 5-31,
5-32, 5-33, 5-34, 5-35
timing shift, 3-14
tutorial, 3-3
using the Status Screen, 3-3

U
UART, 5-70
units, B-6
upgrading firmware, 2-3, 4-15, 5-113
UTC, 5-7
UTC time, 3-16
UTC timeline, 5-73

V
visible satellites, 5-25

W
Windows program
Receiver Status screen, C-2

X
XON, 5-104
XYZ, B-11

T
Table
command list, 4-16, 4-17
factory instrument settings, 5-110,
5-111
factory serial port settings, 5-110
status reporting system, 5-49
terminator
command, B-7
test record, D-2
test result, 5-72
TFOM, 4-7, 5-32, 5-74
TFOM value, 3-13
time and date outputs, 4-6, 4-10, 5-8,
5-73, 5-74, 5-75, 5-76, 5-77
time of day outputs, 4-6, 4-10, 5-8, 5-73,
5-74, 5-75, 5-76, 5-77
Time Stamp memory, 4-12
time stamp polarity, 4-12, 5-89, 5-90
time stamping, 4-12, 5-89, 5-90, 5-91,
5-92, 5-93, 5-94, 5-95, 5-96, 5-97, 5-98,
5-99

General Index-8

Operating and Programming Guide



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