U Blox5 Protocol Specifications

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Specification
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u-blox 5
NMEA, UBX Protocol Specification
u-blox 5 GNSS Receiver
Public Release
Title NMEA, UBX Protocol Specification
Subtitle u-blox 5 GNSS Receiver Public Release
Doc Type Specification
Doc Id GPS.G5-X-07036-D
Revision Date Author Status / Comment
29328 12 Aug 2008 EF Draft
This document and the use of any information contained therein, is subject to the acceptance of the u-blox
terms and conditions. They can be downloaded from www.u-blox.com. u-blox makes no warranties based on
the accuracy or completeness of the contents of this document and reserves the right to make changes to
specifications and product descriptions at any time without notice. u-blox reserves all rights to this document
and the information contained herein. Reproduction, use or disclosure to third parties without express
permission is strictly prohibited. Copyright © 2008, u-blox AG.
For most recent documents, please visit www.u-blox.com
NMEA, UBX Protocol Specification, u-blox 5 GNSS Receiver
GPS.G5-X-07036-D Public Release
Receiver Description
Serial Communication Ports Description
The u-blox 5 positioning technology comes with a highly flexible communication interface. It supports both the
NMEA and the proprietary UBX protocol. It is truly multi-port and multi-protocol capable. Each protocol (UBX,
NMEA) can be assigned to several ports at the same time (multi-port capability) with individual settings (e.g.
baud rate, messages enabled, etc.) for each port. It is even possible to assign more than one protocol (e.g. UBX
protocol and NMEA at the same time) to a single port (multi-protocol capability), which is particularly useful for
debugging purposes.
The UBX and/or NMEA protocol must be activated to get a message on a port using the UBX proprietary
message UBX-CFG-PRT, which also allows to change port-specific settings (baud rate, address etc.). See
CFG-MSG for a description of the mechanism of enabling and disabling messages.
UART Ports
The receivers feature one or two universal asynchronous receiver/transmitter (UART) ports that can be used to
transmit GPS measurements, monitor status information and configure the receiver. The availability of the
second port depends on the type of module or chip set (see our online product selector matrix for modules and
chip sets).
The serial ports consist of an RX and a TX line. Neither handshaking signals nor hardware flow control signals
are available. These serial ports operate in asynchronous mode. The baud rates can be configured individually
for each serial port. However, there is no support for setting different baud rates for reception and transmission
or for different protocols on the same port.
Possible UART Interface Configurations
Baud Rate Data Bits Parity Stop Bits
4800 8 none 1
9600 8 none 1
19200 8 none 1
38400 8 none 1
57600 8 none 1
115200 8 none 1
If too much data is being configured for a certain port's bandwidth (e.g. all UBX messages shall be
output on a UART port with a baud rate of 9600), the buffer will fill up. Once the buffer's space is
exceeded, the receiver will deactivate messages automatically.
Please note that for protocols such as NMEA or UBX, it does not make sense to change the default values of
word length (data bits) since these properties are defined by the protocol, not by the electrical interface.
See CFG-PRT for UART for a description on the contents of the UART port configuration message.
USB Port
The receivers feature one USB (Universal Serial Bus) port, depending on the type of module or chip set (see our
online product selector matrix for modules and chip sets). This port can be used not only for communication
purposes, but also to power the GPS receiver.
The USB interface supports two different power modes:
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•In the Self Powered Mode the receiver is powered by its own power supply. VDDUSB is used to detect the
availability of the USB port, i.e. whether the the receiver is connected to a USB host.
•In the Bus Powered Mode the device is powered by the USB bus, therefore no additional power supply is
needed. The default maximum current that can be drawn by the receiver is 120mA in that mode. See
CFG-USB for a description on how to change this maximum. Configuring the Bus Powered Mode implies
that the device enters a low power state with disabled GPS functionality when the host suspends the device,
e.g. when the host is put into stand-by mode.
The voltage range for VDDUSB is specified from 3.0V to 3.6V, which differs slightly from the
specification for VCC
DDC Port
A DDC Bus (Display Data Channel) is implemented, which is a 2-wire communication interface compatible with
the I2C standard (Inter-Integrated Circuit). Its availability is depending on the type of module or chip set (see
our online product selector matrix for modules and chip sets).
In contrast to all other interfaces, the DDC is not able to communicate in full-duplex mode, i.e. TX and RX are
mutually exclusive. u-blox 5 acts as a slave in the communication setup, therefore it cannot initiate data
transfers on its own. The master provides the data clock, therefore master and slave don't need to be
configured to use the same baud rate. Moreover, a baud rate setting is not applicable for the slave.
The baud rate clock provided by the master must not exceed 100kHz
The receiver's DDC address is set to 0x42 by default. This address can be changed by setting the mode field in
CFG-PRT for DDC accordingly.
As the receiver will be run in slave mode and the physical layer lacks a handshake mechanism to inform the
master about data availability, a layer has been inserted between the physical layer and the UBX and NMEA
layer. The DDC implements a simple streaming interface that allows the constant polling of data, discarding
everything that is not parseable. This means that the receiver returns 0xFF if no data is available.
If no data is polled for an extended period, the receiver temporarily stops writing data to the output buffer to
prevent overflowing.
Read Access
To allow both polled access to the full message stream and quick access to the key data, the register layout
depicted in Figure DDC Register Layout is provided. The data registers 0 to 252, at addresses 0x00 to 0xFC,
each 1 byte in size, contain information to be defined at a later point in time. At addresses 0xFD and 0xFE, the
currently available number of bytes in the message stream can be read. At address 0xFF, the message stream is
located. Subsequent reads from 0xFF return the messages in the transmit buffer, byte by byte. If the number of
bytes read exceeds the number of bytes indicated, the payload is padded using the value 0xFF.
The registers 0x00 to 0xFC will be defined in a later firmware release. Do not use them, as they
don't provide any meaningful data!
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DDC Register Layout
Random Read Access
Random read operations allow the master to access any register in a random manner. To perform this type of
read operation, first the register address to read from must be written to the receiver (see Figure DDC Random
Read Access). Following the start condition from the master, the 7-bit device address including the RW bit
(which is a logic low for write access) are clocked onto the bus by the master transmitter. The receiver answers
with an acknowledge (logic low) to indicate that it is responsible for the given address. Next, the 8-bit address
of the register to be read must be written to the bus. Following the receiver’s acknowledge, the master again
triggers a start condition and writes the device address, but this time the RW bit is a logic high to initiate the
read access. Now, the master can read 1 to N bytes from the receiver, generating a not-acknowledge and a
stop condition after the last byte being read. After every byte being read, the internal address counter is
incremented by one, saturating at 0xFF. This saturation means, that, after having read all registers coming after
the initially set register address, the raw message stream can be read.
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DDC Random Read Access
Current Address Read
The receiver contains an address counter that maintains the address of the last register accessed, internally
incremented by one. Therefore, if the previous read access was to address n (n is any legal address), the next
current address read operation would access data from address n+1 (see Figure DDC Current Address Read
Access). Upon receipt of the device address with the RW bit set to one, the receiver issues an acknowledge and
the master can read 1 to N bytes from the receiver, generating a not-acknowledge and a stop condition after
the last byte being read.
To allow direct access to streaming data, the internal address counter is initialized to 0xFF, meaning that
current address reads without a preceding random read access return the raw message stream. The address
counter can be set to another address at any point in time using a random read access.
DDC Current Address Read Access
Write Access
The receiver does not provide any write access except for writing UBX messages (and NMEA messages) to the
receiver, such as configuration or aiding data. Therefore, the register set mentioned in section Read Access is
not writable. Following the start condition from the master, the 7-bit device address including the RW bit (which
NMEA, UBX Protocol Specification, u-blox 5 GNSS Receiver
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is a logic low for write access) are clocked onto the bus by the master transmitter. The receiver answers with an
acknowledge (logic low) to indicate that it is responsible for the given address. Now, the master can write 2 to
N bytes to the receiver, generating stop condition after the last byte being written. The number of bytes must
exceed 2 to properly distinguish from the write access to set the address counter in random read accesses.
DDC Write Access
SPI Port
An SPI Bus (Serial Peripheral Interface is provided, depending on the type of module or chip set (see our online
product selector matrix for modules and chip sets). The SPI is a 3-wire synchronous communication interface; In
contrast to UART the master provides a clock, meaning that master and slave don't need to be configured to
use the same baud rate. Moreover, a baud rate setting is not applicable for the slave. SPI modes 0-3 are
implemented and can be configured using the field mode.spiMode in CFG-PRT for SPI (default is SPI mode 0).
The baud rate clock provided by the master must not exceed 250kHz
Read Access
As the register mode is not implemented for the SPI port, only the UBX/NMEA message stream is provided. This
stream is accessed using the Back-To-Back Read and Write Access (see section Back-To-Back Read and Write
Access). When no data is available to be written to the receiver, MOSI should be held logic high, i.e. all bytes
written to the receiver are set to 0xFF.
In order to prevent the receiver from being busy parsing the incoming data, the parsing process is stopped after
20 subsequent bytes containing 0xFF. The parsing process gets re-enabled with the first byte not equal to 0xFF.
The number of bytes to wait for deactivation (20 by default) can be adjusted using the field mode.ffCnt in
CFG-PRT for SPI.
If the receiver has no more data to send, it pulls MISO to logic high, i.e. all bytes transmitted are set to 0xFF.
This means that the master should ignore all 0xFF which are not part of a message. It can resume data
processing as soon as the first byte not equalling 0xFF is received.
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Back-To-Back Read and Write Access
The receiver does not provide any write access except for writing UBX messages (and eventually NMEA
messages) to the receiver, such as configuration or aiding data. For every byte written to the receiver, a byte
must be read from the receiver; the master writes to MOSI and, at the same time, it reads from MISO. The data
on MISO represents the results from a current address read, returning 0xFF when no more data is available.
SPI Back-To-Back Read/Write Access
How to change between protocols
Reconfiguring a port from one protocol to another is a two-step process. First of all, the preferred protocol(s)
needs to be enabled to a port using CFG-PRT. One port can handle several protocols at the same time (e.g.
NMEA and UBX). By default, all ports are configured for UBX and NMEA protocol so in most cases, it’s not
necessary to change the port settings at all. Port settings can be viewed and changed using the CFG-PRT
messages.
As a second step, activate certain messages on each port using CFG-MSG.
Despite the fact that concatenation of several configurations is still possible on receivers before
u-blox 5, the use of this feature is discouraged as it won't work on u-blox 5. u-blox 5 has 6 I/O
ports, so backwards compatibility is dropped at this point.
This message can be used to initiate receiver restart scenarios, optionally erasing information the receiver has
acquired.
Typically, in GPS receivers, one distinguishes between Cold-, Warm- and Hotstarts, depending on the type of
valid information the receiver has at the time of the restart.
•Coldstart In this startup mode, the receiver has no a-priori information on last position, time, velocity,
frequency etc. Therefore, the receiver has to search the full time- and frequency space, and also all possible
satellite numbers. If a satellite signal is found, it is being tracked to decode ephemeris (18-36 seconds under
strong signal conditions), whereas the other channels continue to search satellites. Once there are sufficient
number of satellites with valid ephemeris, the receiver can calculate position- and velocity data. Please note
that some competitors call this startup mode Factory Startup.
•Warmstart In warmstart mode, the receiver has approximate information of time, position, and coarse data
on Satellite positions (Almanac). In this mode, after power-up, the receiver basically needs to download
ephemeris until it can calculate position- and velocity data. As the ephemeris data usually is outdated after 4
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hours, the receiver will typically start with a warmstart if it was powered down for more than that amount of
time. For this scenario, several augmentations exist. See the sections on AssistNOW online and offline.
•Hotstart In Hotstart, the receiver was powered down only for a short time (4 hours or less), so that its
ephemeris is still valid. Since the receiver doesn't need to download ephemeris again, this is the fastest
startup method.
In the UBX-CFG-RST message, one can force the receiver to reset and clear data, in order to see the effects of
maintaining/losing such a-priori data between restarts. For that, the CFG-RST message offers the navBbrMask
field, where Hot-, Warm- and Coldstarts can be initiated, and also other combinations thereof.
The Reset Type can also be specified. This is not GPS-related, but the way the software restarts the system.
•Hardware Reset uses the on-chip Watchdog, in order to electrically reset the chip. This is an immediate,
asynchronous reset. No Stop events are generated. This is equivalent to pulling the Reset signal on the
receiver.
•Controlled Software Reset terminates all running processes in an orderly manner and, once the system is
idle, restarts operation, reloads its configuration and starts to acquire and track GPS satellites
•Controlled Software Reset (GPS only) only restarts the GPS tasks, without reinitializing the full system or
reloading any stored configuration.
•Controlled GPS Stop stops all GPS tasks. The receiver will not be restarted, but will stop any GPS related
processing.
•Controlled GPS Start starts all GPS tasks.
Geodetic Datum
Predefined Datum
The following, predefined Datum Values are available and can be configured using UBX message CFG-DAT.
For the ellipsoid parameters, see ellipsoid section below. For the rotation and scale parameters, see rotation and
scale section below.
The receiver defaults to WGS84 datum
Geodetic Datum Defined in Firmware
Index Description Short Ellipsoid
Index
Rotation,
Scale
dX [m] dY [m] dZ [m]
0 World Geodetic System - 84 WGS84 0 0 0.0 0.0 0.0
1 World Geodetic System - 72 WGS72 23 1 0.0 0.0 4.5
2 Earth-90 - GLONASS Coordinate system ETH90 8 0 0.0 0.0 4.0
3 Adindan - Mean Solution (Ethiopia & Sudan) ADI-M 7 0 -166.0 -15.0 204.0
4 Adindan - Burkina Faso ADI-E 7 0 -118.0 -14.0 218.0
5 Adindan - Cameroon ADI-F 7 0 -134.0 -2.0 210.0
6 Adindan - Ethiopia ADI-A 7 0 -165.0 -11.0 206.0
7 Adindan - Mali ADI-C 7 0 -123.0 -20.0 220.0
8 Adindan - Senegal ADI-D 7 0 -128.0 -18.0 224.0
9 Adindan - Sudan ADI-B 7 0 -161.0 -14.0 205.0
10 Afgooye - Somalia AFG 21 0 -43.0 -163.0 45.0
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Geodetic Datum Defined in Firmware continued
Index Description Short Ellipsoid
Index
Rotation,
Scale
dX [m] dY [m] dZ [m]
11 ARC 1950 - Mean (Botswana, Lesotho, Malawi,
Swaziland, Zaire, Zambia, Zimbabwe)
ARF-M 7 0 -143.0 -90.0 -294.0
12 ARC 1950 - Botswana ARF-A 7 0 -138.0 -105.0 -289.0
13 ARC 1950 - Burundi ARF-H 7 0 -153.0 -5.0 -292.0
14 ARC 1950 - Lesotho ARF-B 7 0 -125.0 -108.0 -295.0
15 ARC 1950 - Malawi ARF-C 7 0 -161.0 -73.0 -317.0
16 ARC 1950 - Swaziland ARF-D 7 0 -134.0 -105.0 -295.0
17 ARC 1950 - Zaire ARF-E 7 0 -169.0 -19.0 -278.0
18 ARC 1950 - Zambia ARF-F 7 0 -147.0 -74.0 -283.0
19 ARC 1950 - Zimbabwe ARF-G 7 0 -142.0 -96.0 -293.0
20 ARC 1960 - Mean (Kenya, Tanzania) ARS 7 0 -160.0 -6.0 -302.0
21 Ayabelle Lighthouse - Djibouti PHA 7 0 -79.0 -129.0 145.0
22 Bissau - Guinea-Bissau BID 20 0 -173.0 253.0 27.0
23 Cape - South Africa CAP 7 0 -136.0 -108.0 -292.0
24 Carthage - Tunisia CGE 7 0 -263.0 6.0 431.0
25 Dabola - Guinea DAL 7 0 -83.0 37.0 124.0
26 Leigon - Ghana LEH 7 0 -130.0 29.0 364.0
27 Liberia 1964 LIB 7 0 -90.0 40.0 88.0
28 Massawa - Eritrea (Ethiopia) MAS 5 0 639.0 405.0 60.0
29 Merchich - Morocco MER 7 0 31.0 146.0 47.0
30 Minna - Cameroon MIN-A 7 0 -81.0 -84.0 115.0
31 Minna - Nigeria MIN-B 7 0 -92.0 -93.0 122.0
32 M'Poraloko - Gabon MPO 7 0 -74.0 -130.0 42.0
33 North Sahara 1959 - Algeria NSD 7 0 -186.0 -93.0 310.0
34 Old Egyptian 1907 - Egypt OEG 17 0 -130.0 110.0 -13.0
35 Point 58 - Mean Solution (Burkina Faso & Niger) PTB 7 0 -106.0 -129.0 165.0
36 Pointe Noire 1948 - Congo PTN 7 0 -148.0 51.0 -291.0
37 Schwarzeck - Namibia SCK 5 0 616.0 97.0 -251.0
38 Voirol 1960 - Algeria VOR 7 0 -123.0 -206.0 219.0
39 Ain El Abd 1970 - Bahrain Island AIN-A 20 0 -150.0 -250.0 -1.0
40 Ain El Abd 1970 - Saudi Arabia AIN-B 20 0 -143.0 -236.0 7.0
41 Djakarta (Batavia)- Sumatra (Indonesia) BAT 5 0 -377.0 681.0 -50.0
42 Hong Kong 1963 - Hong Kong HKD 20 0 -156.0 -271.0 -189.0
43 Hu-Tzu-Shan - Taiwan HTN 20 0 -637.0 -549.0 -203.0
44 Indian - Bangladesh IND-B 9 0 282.0 726.0 254.0
45 Indian - India & Nepal IND-I 11 0 295.0 736.0 257.0
46 Indian 1954 - Thailand INF-A 9 0 217.0 823.0 299.0
47 Indian 1960 - Vietnam (near 16N) ING-A 9 0 198.0 881.0 317.0
48 Indian 1960 - Con Son Island (Vietnam) ING-B 9 0 182.0 915.0 344.0
49 Indian 1975 - Thailand INH-A 9 0 209.0 818.0 290.0
50 Indonesian 1974 IDN 19 0 -24.0 -15.0 5.0
51 Kandawala - Sri Lanka KAN 9 0 -97.0 787.0 86.0
52 Kertau 1948 - West Malaysia & Singapore KEA 13 0 -11.0 851.0 5.0
53 Nahrwan - Masirah Island (Oman) NAH-A 7 0 -247.0 -148.0 369.0
54 Nahrwan - United Arab Emirates NAH-B 7 0 -249.0 -156.0 381.0
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Geodetic Datum Defined in Firmware continued
Index Description Short Ellipsoid
Index
Rotation,
Scale
dX [m] dY [m] dZ [m]
55 Nahrwan - Saudi Arabia NAH-C 7 0 -243.0 -192.0 477.0
56 Oman FAH 7 0 -346.0 -1.0 224.0
57 Qatar National - Qatar QAT 20 0 -128.0 -283.0 22.0
58 South Asia - Singapore SOA 15 0 7.0 -10.0 -26.0
59 Timbalai 1948 - Brunei & East Malaysia
(Sarawak & Sabah)
TIL 10 0 -679.0 669.0 -48.0
60 Tokyo - Mean Solution (Japan,Okinawa &
South Korea)
TOY-M 5 0 -148.0 507.0 685.0
61 Tokyo - Japan TOY-A 5 0 -148.0 507.0 685.0
62 Tokyo - Okinawa TOY-C 5 0 -158.0 507.0 676.0
63 Tokyo - South Korea TOY-B 5 0 -146.0 507.0 687.0
64 Australian Geodetic 1966 - Australia &
Tasmania
AUA 3 0 -133.0 -48.0 148.0
65 Australian Geodetic 1984 - Australia &
Tasmania
AUG 3 0 -134.0 -48.0 149.0
66 European 1950 - Mean (AU, B, DK, FN, F, G,
GR, I, LUX, NL, N, P, E, S, CH)
EUR-M 20 0 -87.0 -98.0 -121.0
67 European 1950 - Western Europe (AU, DK, FR,
G, NL, CH)
EUR-A 20 0 -87.0 -96.0 -120.0
68 European 1950 - Cyprus EUR-E 20 0 -104.0 -101.0 -140.0
69 European 1950 - Egypt EUR-F 20 0 -130.0 -117.0 -151.0
70 European 1950 - England, Wales, Scotland &
Channel Islands
EUR-G 20 0 -86.0 - 96.0 -120.0
71 European 1950 - England, Wales, Scotland &
Ireland
EUR-K 20 0 -86.0 - 96.0 -120.0
72 European 1950 - Greece EUR-B 20 0 -84.0 -95.0 -130.0
73 European 1950 - Iran EUR-H 20 0 -117.0 -132.0 -164.0
74 European 1950 - Italy - Sardinia EUR-I 20 0 -97.0 -103.0 -120.0
75 European 1950 - Italy - Sicily EUR-J 20 0 -97.0 -88.0 -135.0
76 European 1950 - Malta EUR-L 20 0 -107.0 -88.0 -149.0
77 European 1950 - Norway & Finland EUR-C 20 0 -87.0 -95.0 -120.0
78 European 1950 - Portugal & Spain EUR-D 20 0 -84.0 -107.0 -120.0
79 European 1950 - Tunisia EUR-T 20 0 -112.0 -77.0 -145.0
80 European 1979 - Mean Solution (AU, FN, NL, N,
E, S, CH)
EUS 20 0 -86.0 -98.0 -119.0
81 Hjorsey 1955 - Iceland HJO 20 0 -73.0 46.0 -86.0
82 Ireland 1965 IRL 2 0 506.0 -122.0 611.0
83 Ordnance Survey of GB 1936 - Mean (E, IoM, S,
ShI, W)
OGB-M 1 0 375.0 -111.0 431.0
84 Ordnance Survey of GB 1936 - England OGB-A 1 0 371.0 -112.0 434.0
85 Ordnance Survey of GB 1936 - England, Isle of
Man & Wales
OGB-B 1 0 371.0 -111.0 434.0
86 Ordnance Survey of GB 1936 - Scotland &
Shetland Isles
OGB-C 1 0 384.0 -111.0 425.0
87 Ordnance Survey of GB 1936 - Wales OGB-D 1 0 370.0 -108.0 434.0
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Geodetic Datum Defined in Firmware continued
Index Description Short Ellipsoid
Index
Rotation,
Scale
dX [m] dY [m] dZ [m]
88 Rome 1940 - Sardinia Island MOD 20 0 -225.0 -65.0 9.0
89 S-42 (Pulkovo 1942) - Hungary SPK 21 0 28.0 -121.0 -77.0
90 S-JTSK Czechoslavakia (prior to 1 Jan 1993) CCD 5 0 589.0 76.0 480.0
91 Cape Canaveral - Mean Solution (Florida &
Bahamas)
CAC 6 0 -2.0 151.0 181.0
92 N. American 1927 - Mean Solution (CONUS) NAS-C 6 0 -8.0 160.0 176.0
93 N. American 1927 - Western US NAS-B 6 0 -8.0 159.0 175.0
94 N. American 1927 - Eastern US NAS-A 6 0 -9.0 161.0 179.0
95 N. American 1927 - Alaska (excluding Aleutian
Islands)
NAS-D 6 0 -5.0 135.0 172.0
96 N. American 1927 - Aleutian Islands, East of
180W
NAS-V 6 0 -2.0 152.0 149.0
97 N. American 1927 - Aleutian Islands, West of
180W
NAS-W 6 0 2.0 204.0 105.0
98 N. American 1927 - Bahamas (excluding San
Salvador Island)
NAS-Q 6 0 -4.0 154.0 178.0
99 N. American 1927 - San Salvador Island NAS-R 6 0 1.0 140.0 165.0
100 N. American 1927 - Canada Mean Solution
(including Newfoundland)
NAS-E 6 0 -10.0 158.0 187.0
101 N. American 1927 - Alberta & British Columbia NAS-F 6 0 -7.0 162.0 188.0
102 N. American 1927 - Eastern Canada
(Newfoundland, New Brunswick, Nova Scotia &
Quebec)
NAS-G 6 0 -22.0 160.0 190.0
103 N. American 1927 - Manitoba & Ontario NAS-H 6 0 -9.0 157.0 184.0
104 N. American 1927 - Northwest Territories &
Saskatchewan
NAS-I 6 0 4.0 159.0 188.0
105 N. American 1927 - Yukon NAS-J 6 0 -7.0 139.0 181.0
106 N. American 1927 - Canal Zone NAS-O 6 0 0.0 125.0 201.0
107 N. American 1927 - Caribbean NAS-P 6 0 -3.0 142.0 183.0
108 N. American 1927 - Central America NAS-N 6 0 0.0 125.0 194.0
109 N. American 1927 - Cuba NAS-T 6 0 -9.0 152.0 178.0
110 N. American 1927 - Greenland (Hayes
Peninsula)
NAS-U 6 0 11.0 114.0 195.0
111 N. American 1927 - Mexico NAS-L 6 0 -12.0 130.0 190.0
112 N. American 1983 - Alaska (excluding Aleutian
Islands)
NAR-A 16 0 0.0 0.0 0.0
113 N. American 1983 - Aleutian Islands NAR-E 16 0 -2.0 0.0 4.0
114 N. American 1983 - Canada NAR-B 16 0 0.0 0.0 0.0
115 N. American 1983 - Mean Solution (CONUS) NAR-C 16 0 0.0 0.0 0.0
116 N. American 1983 - Hawaii NAR-H 16 0 1.0 1.0 -1.0
117 N. American 1983 - Mexico & Central America NAR-D 16 0 0.0 0.0 0.0
118 Bogota Observatory - Colombia BOO 20 0 307.0 304.0 -318.0
119 Campo Inchauspe 1969 - Argentina CAI 20 0 -148.0 136.0 90.0
120 Chua Astro - Paraguay CHU 20 0 -134.0 229.0 -29.0
121 Corrego Alegre - Brazil COA 20 0 -206.0 172.0 -6.0
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Geodetic Datum Defined in Firmware continued
Index Description Short Ellipsoid
Index
Rotation,
Scale
dX [m] dY [m] dZ [m]
122 Prov S. American 1956 - Mean Solution (Bol,
Col, Ecu, Guy, Per & Ven)
PRP-M 20 0 -288.0 175.0 -376.0
123 Prov S. American 1956 - Bolivia PRP-A 20 0 -270.0 188.0 -388.0
124 Prov S. American 1956 - Northern Chile (near
19S)
PRP-B 20 0 -270.0 183.0 -390.0
125 Prov S. American 1956 - Southern Chile (near
43S)
PRP-C 20 0 -305.0 243.0 -442.0
126 Prov S. American 1956 - Colombia PRP-D 20 0 -282.0 169.0 -371.0
127 Prov S. American 1956 - Ecuador PRP-E 20 0 -278.0 171.0 -367.0
128 Prov S. American 1956 - Guyana PRP-F 20 0 -298.0 159.0 -369.0
129 Prov S. American 1956 - Peru PRP-G 20 0 -279.0 175.0 -379.0
130 Prov S. American 1956 - Venezuela PRP-H 20 0 -295.0 173.0 -371.0
131 Prov South Chilean 1963 HIT 20 0 16.0 196.0 93.0
132 South American 1969 - Mean Solution (Arg,
Bol, Bra, Chi, Col, Ecu, Guy, Par, Per, Tri & Tob,
Ven)
SAN-M 22 0 -57.0 1.0 -41.0
133 South American 1969 - Argentina SAN-A 22 0 -62.0 -1.0 -37.0
134 South American 1969 - Bolivia SAN-B 22 0 -61.0 2.0 -48.0
135 South American 1969 - Brazil SAN-C 22 0 -60.0 -2.0 -41.0
136 South American 1969 - Chile SAN-D 22 0 -75.0 -1.0 -44.0
137 South American 1969 - Colombia SAN-E 22 0 -44.0 6.0 -36.0
138 South American 1969 - Ecuador (excluding
Galapagos Islands)
SAN-F 22 0 -48.0 3.0 -44.0
139 South American 1969 - Baltra, Galapagos
Islands
SAN-J 22 0 -47.0 26.0 -42.0
140 South American 1969 - Guyana SAN-G 22 0 -53.0 3.0 -47.0
141 South American 1969 - Paraguay SAN-H 22 0 -61.0 2.0 -33.0
142 South American 1969 - Peru SAN-I 22 0 -58.0 0.0 -44.0
143 South American 1969 - Trinidad & Tobago SAN-K 22 0 -45.0 12.0 -33.0
144 South American 1969 - Venezuela SAN-L 22 0 -45.0 8.0 -33.0
145 Zanderij - Suriname ZAN 20 0 -265.0 120.0 -358.0
146 Antigua Island Astro 1943 - Antigua, Leeward
Islands
AIA 7 0 -270.0 13.0 62.0
147 Ascension Island 1958 ASC 20 0 -205.0 107.0 53.0
148 Astro Dos 71/4 - St Helena Island SHB 20 0 -320.0 550.0 -494.0
149 Bermuda 1957 - Bermuda Islands BER 6 0 -73.0 213.0 296.0
150 Deception Island, Antarctica DID 7 0 260.0 12.0 -147.0
151 Fort Thomas 1955 - Nevis, St Kitts, Leeward
Islands
FOT 7 0 -7.0 215.0 225.0
152 Graciosa Base SW 1948 - Faial, Graciosa, Pico,
Sao Jorge, Terceira Islands (Azores)
GRA 20 0 -104.0 167.0 -38.0
153 ISTS 061 Astro 1968 - South Georgia Islands ISG 20 0 -794.0 119.0 -298.0
154 L.C. 5 Astro 1961 - Cayman Brac Island LCF 6 0 42.0 124.0 147.0
155 Montserrat Island Astro 1958 - Montserrat
Leeward Islands
ASM 7 0 174.0 359.0 365.0
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Geodetic Datum Defined in Firmware continued
Index Description Short Ellipsoid
Index
Rotation,
Scale
dX [m] dY [m] dZ [m]
156 Naparima, BWI - Trinidad & Tobago NAP 20 0 -10.0 375.0 165.0
157 Observatorio Meteorologico 1939 - Corvo and
Flores Islands (Azores)
FLO 20 0 -425.0 -169.0 81.0
158 Pico De Las Nieves - Canary Islands PLN 20 0 -307.0 -92.0 127.0
159 Porto Santo 1936 - Porto Santo and Madeira
Islands
POS 20 0 -499.0 -249.0 314.0
160 Puerto Rico - Puerto Rico & Virgin Islands PUR 6 0 11.0 72.0 -101.0
161 Qornoq - South Greenland QUO 20 0 164.0 138.0 -189.0
162 Sao Braz - Soa Miguel, Santa Maria Islands
(Azores)
SAO 20 0 -203.0 141.0 53.0
163 Sapper Hill 1943 - East Falkland Island SAP 20 0 -355.0 21.0 72.0
164 Selvagem Grande 1938 - Salvage Islands SGM 20 0 -289.0 -124.0 60.0
165 Tristan Astro 1968 - Tristan du Cunha TDC 20 0 -632.0 438.0 -609.0
166 Anna 1 Astro 1965 - Cocos Islands ANO 3 0 -491.0 -22.0 435.0
167 Gandajika Base 1970 - Republic of Maldives GAA 20 0 -133.0 -321.0 50.0
168 ISTS 073 Astro 1969 - Diego Garcia IST 20 0 208.0 -435.0 -229.0
169 Kerguelen Island 1949 - Kerguelen Island KEG 20 0 145.0 -187.0 103.0
170 Mahe 1971 - Mahe Island MIK 7 0 41.0 -220.0 -134.0
171 Reunion - Mascarene Islands RUE 20 0 94.0 -948.0 -1262.0
172 American Samoa 1962 - American Samoa
Islands
AMA 6 0 -115.0 118.0 426.0
173 Astro Beacon E 1945 - Iwo Jima ATF 20 0 145.0 75.0 -272.0
174 Astro Tern Island (Frig) 1961 - Tern Island TRN 20 0 114.0 -116.0 -333.0
175 Astronomical Station 1952 - Marcus Island ASQ 20 0 124.0 -234.0 -25.0
176 Bellevue (IGN) - Efate and Erromango Islands IBE 20 0 -127.0 -769.0 472.0
177 Canton Astro 1966 - Phoenix Islands CAO 20 0 298.0 -304.0 -375.0
178 Chatham Island Astro 1971 - Chatham Island
(New Zeland)
CHI 20 0 175.0 -38.0 113.0
179 DOS 1968 - Gizo Island (New Georgia Islands) GIZ 20 0 230.0 -199.0 -752.0
180 Easter Island 1967 - Easter Island EAS 20 0 211.0 147.0 111.0
181 Geodetic Datum 1949 - New Zealand GEO 20 0 84.0 -22.0 209.0
182 Guam 1963 - Guam Island GUA 6 0 -100.0 -248.0 259.0
183 GUX 1 Astro - Guadalcanal Island DOB 20 0 252.0 -209.0 -751.0
184 Indonesian 1974 - Indonesia IDN 19 0 -24.0 -15.0 5.0
185 Johnston Island 1961 - Johnston Island JOH 20 0 189.0 -79.0 -202.0
186 Kusaie Astro 1951 - Caroline Islands, Fed.
States of Micronesia
KUS 20 0 647.0 1777.0 -1124.0
187 Luzon - Philippines (excluding Mindanao Island) LUZ-A 6 0 -133.0 -77.0 -51.0
188 Luzon - Mindanao Island (Philippines) LUZ-B 6 0 -133.0 -79.0 -72.0
189 Midway Astro 1961 - Midway Islands MID 20 0 912.0 -58.0 1227.0
190 Old Hawaiian - Mean Solution OHA-M 6 0 61.0 -285.0 -181.0
191 Old Hawaiian - Hawaii OHA-A 6 0 89.0 -279.0 -183.0
192 Old Hawaiian - Kauai OHA-B 6 0 45.0 -290.0 -172.0
193 Old Hawaiian - Maui OHA-C 6 0 65.0 -290.0 -190.0
194 Old Hawaiian - Oahu OHA-D 6 0 58.0 -283.0 -182.0
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Geodetic Datum Defined in Firmware continued
Index Description Short Ellipsoid
Index
Rotation,
Scale
dX [m] dY [m] dZ [m]
195 Pitcairn Astro 1967 - Pitcairn Island PIT 20 0 185.0 165.0 42.0
196 Santo (Dos) 1965 - Espirito Santo Island SAE 20 0 170.0 42.0 84.0
197 Viti Levu 1916 - Viti Levu Island (Fiji Islands) MVS 7 0 51.0 391.0 -36.0
198 Wake-Eniwetok 1960 - Marshall Islands ENW 18 0 102.0 52.0 -38.0
199 Wake Island Astro 1952 - Wake Atoll WAK 20 0 276.0 -57.0 149.0
200 Bukit Rimpah - Bangka and Belitung Islands
(Indonesia)
BUR 5 0 -384.0 664.0 -48.0
201 Camp Area Astro - Camp McMurdo Area,
Antarctica
CAZ 20 0 -104.0 -129.0 239.0
202 European 1950 - Iraq, Israel, Jordan, Kuwait,
Lebanon, Saudi Arabia & Syria
EUR-S 20 0 -103.0 -106.0 -141.0
203 Gunung Segara - Kalimantan (Indonesia) GSE 5 0 -403.0 684.0 41.0
204 Herat North - Afghanistan HEN 20 0 -333.0 -222.0 114.0
205 Indian - Pakistan IND-P 9 0 283.0 682.0 231.0
206 Pulkovo 1942 - Russia PUK 21 0 28.0 -130.0 -95.0
207 Tananarive Observatory 1925 - Madagascar TAN 20 0 -189.0 -242.0 -91.0
208 Yacare - Uruguay YAC 20 0 -155.0 171.0 37.0
209 Krassovsky 1942 - Russia KRA42 21 0 26.0 -139.0 -80.0
210 Lommel Datum 1950 - Belgium & Luxembourg BLG50 20 0 -55.0 49.0 -158.0
211 Reseau National Belge 1972 - Belgium RNB72 20 0 -104.0 80.0 -75.0
212 NTF - Nouvelle Triangulation de la France NTF 7 0 -168.0 -60.0 320.0
213 Netherlands 1921 - Netherlands NL21 5 0 719.0 47.0 640.0
214 European Datum 1987, IAG RETrig
Subcommision.
ED87 20 2 -82.5 -91.7 -117.7
215 Swiss Datum 1903+ (LV95) CH95 5 0 674.374 15.056 405.346
Ellipsoids
Ellipsoids
Index Description Semi Major Axis [m] Flattening
0 WGS 84 6378137.000 298.257223563
1 Airy 1830 6377563.396 299.3249646
2 Modified Airy 6377340.189 299.3249646
3 Australian National 6378160.000 298.25
4 Bessel 1841 (Namibia) 6377483.865 299.1528128
5 Bessel 1841 6377397.155 299.1528128
6 Clarke 1866 6378206.400 294.9786982
7 Clarke 1880 6378249.145 293.465
8 Earth-90 6378136.000 298.257839303
9 Everest (India 1830) 6377276.345 300.8017
10 Everest (Sabah Sarawak) 6377298.556 300.8017
11 Everest (India 1956) 6377301.243 300.8017
12 Everest (Malaysia 1969) 6377295.664 300.8017
13 Everest (Malay. & Singapore 1948) 6377304.063 300.8017
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Ellipsoids continued
Index Description Semi Major Axis [m] Flattening
14 Everest (Pakistan) 6377309.613 300.8017
15 Modified Fischer 1960 6378155.000 298.3
16 GRS 80 6378137.000 298.257222101
17 Helmert 1906 6378200.000 298.3
18 Hough 1960 6378270.000 297.0
19 Indonesian 1974 6378160.000 298.247
20 International 1924 6378388.000 297.0
21 Krassovsky 1940 6378245.000 298.3
22 South American 1969 6378160.000 298.25
23 WGS 72 6378135.000 298.26
Rotation and Scale
Rotation and Scale
Index Description Rot X
[seconds]
Rot Y
[seconds]
Rot Z
[seconds]
Scale
0 +0.0000 +0.0000 +0.0000 0.000
1 +0.0000 +0.0000 -0.5540 0.220
2 European Datum 1987 IAG RETrig Subcommision. +0.1338 -0.0625 -0.0470 0.045
Timepulse Configuration
The receiver provides a hardware-synchronized timepulse (Pin 29) with a time pulse (TP) period of 1 ms to 60 s.
The polarity (rising or falling edge) and the pulse duration can be configured. Use the UBX proprietary message
CFG-TP to change the timepulse settings. The UBX-TIM-TP message provides the time information for the next
timepulse, time source and a quantization error.
The CFG-TP message comprises the following parameters defining the hardware-synchronized timepulse:
•pulse interval - time interval between timepulses
•pulse length - duration of the timepulse (time period between rising and falling edge)
•pulse mode - if not disabled the synchronization of timepulse can be configured to be done on rising or
falling edge
•time reference - the reference time source (time base) used for timepulse synchronization and timepulse
time given in TIM-TP output message
•synchronization mode - the timepulse can be configured to be always synchronized and will be available
only in this case. If the timepulse is allowed to be asynchronized it will be available at any time even when
the time is not valid.
•antenna cable delay - the signal delay due to the cable between antenna and receiver
•RF group delay - delay of the signal in the RF module of the u-blox 5 receiver (hard coded)
•user delay - the cable delay from u-blox 5 receiver to the user device plus signal delay of any user
application
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Notes:
• The pulse period must be an integer multiple of 60 seconds.
• The maximum pulse length can’t exceed the pulse period minus 1 microsecond.
• A timepulse is only output when the receiver has determined the time with sufficent accuracy and reliability.
Recommendations:
• When using the timepulse for a timing application it is recommended to calibrate the
RF signal delay against a reference-timing source.
•In order to get the best timing accuracy with the antenna, a fixed accurate position is needed. Once the
receiver is in timing mode, the dynamic model does not influence the timing accuracy.
Example:
The example shows the 1PPS timepulse signal generated according the specific parameters of the CFG-TP
message.
NMEA, UBX Protocol Specification, u-blox 5 GNSS Receiver
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Receiver Configuration
Configuration Concept
u-blox 5 positioning technology is fully configurable with UBX protocol configuration messages (message class
UBX-CFG). The configuration used by the u-blox 5 GPS core during normal operation is termed "Current
Configuration". The Current Configuration can be changed during normal operation by sending any
UBX-CFG-XXX message to the receiver over an I/O port. The receiver will change its Current Configuration
immediately after receiving the configuration message. The u-blox 5 GPS core always uses only the Current
Configuration.
Unless the Current Configuration is made permanent by using UBX-CFG-CFG as described below, the Current
Configuration will be lost in case of (see message CFG-RST)
• a power cycle
• a hardware reset
• a (complete) controlled software reset
The Current Configuration can be made permanent (stored in a non-volatile memory) by saving it to the
"Permanent Configuration". This is done by sending a UBX-CFG-CFG message with an appropriate saveMask
(UBX-CFG-CFG/save).
The Permanent Configurations are copied to the Current Configuration after start-up or when a UBX-CFG-CFG
message with an appropriate loadMask (UBX-CFG-CFG/load) is sent to the receiver.
The Permanent Configuration can be restored to the receiver's Default Configuration by sending a
UBX-CFG-CFG message with an appropriate clearMask (UBX-CFG-CFG/clear) to the receiver.
This only replaces the Permanent Configuration, not the Current Configuration. To make the receiver operate
with the Default Configuration which was restored to the Permanent Configuration, a UBX-CFG-CFG/load
command must be sent or the receiver must be reset.
The mentioned masks (saveMask, loadMask, clearMask) are 4 byte bit fields . Every bit represents one
configuration sub-section. These sub-sections are defined in section "Organization of the Configuration
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Sections"). All three masks are part of every UBX-CFG-CFG message. Save, load and clear commands can be
combined in the same message. Order of execution is save, load, clear.
The following diagram illustrates the process:
Organization of the Configuration Sections
The configuration is divided into several sub-sections. Each of these sub-sections corresponds to one or several
UBX-CFG-XXX messages. The sub-section numbers in the following table correspond to the bit position in the
masks mentioned above.
Configuration sub-sections
sub-section CFG messages Description
0 UBX-CFG-PRT
UBX-CFG-USB
Port and USB settings
1 UBX-CFG-MSG Message settings (enable/disable, update rate)
2 UBX-CFG-INF Information output settings (Errors, Warnings, Notice, Test etc.)
3 UBX-CFG-NAV5
UBX-CFG-DAT
UBX-CFG-RATE
UBX-CFG-SBAS
UBX-CFG-NMEA
UBX-CFG-TMODE
Navigation Parameter, Receiver Datum, Measurement and Navigation Rate
setting, Timemode settings, SBAS settings, NMEA protocol settings
4 UBX-CFG-TP Timepulse Settings
5 N/A Reserved for future low power modes
6-9 N/A Reserved for EKF (Dead Reckoning) Receivers
10 UBX-CFG-ANT Antenna configuration
11-31 N/A Reserved
Permanent Configuration Storage Media
The Current Configuration is stored in the receiver's volatile RAM. Hence, any changes made to the Current
Configuration without saving will be lost in the events listed in the section above. By using UBX-CFG-CFG/save,
the selected configuration sub-sections are saved to all non-volatile memories available:
•On-chip BBR (battery backup RAM). In order for the BBR to work, a backup battery must be applied to the
receiver.
• External FLASH memory, where available.
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•External EEPROM (Electrically Erasable Programmable Read-Only Memory), where available via DDC (I2C
compatible).
Receiver Default Configuration
Permanent Configurations can be reset to Default Configurations through a UBX-CFG-CFG/clear message. The
receiver's Default Configuration is determined at system startup. The Default Configuration depends on various
information such as system clock frequency and others. The receiver searches for this information in various
places (memories and configuration pins). Refer to the receiver's data sheet for details.
Power modi for search engine
The receiver determines how and if to search for satellites depending on power configuration (low-level config),
number of satellites tracked and if a valid position could be calculated.
Max. Performance mode
In max. performance mode, the receiver searches for all satellites which are currently not tracked on a channel
and not invisible (as far as information from satellite pre-positioning is available). If no information is available,
the unknown and known-visible satellites are be searched continuously.
Eco mode
In eco mode, if no valid fix could be calculated before, the receiver searches for all satellites with the search
engine as then no assumptions about visibility can be made. After a fix could be calculated, the receiver no
more uses the search engine to search for satellites without pre-positioning information. Pre-positioning
information is available for satellites if orbits for this special SV, and position and time are known at the
receiver. If a confirmed position and time are determined and a sufficient number (more or equal to 4) of
satellites are tracked, the search engine is completely powered off.
Remark that even if the search engine is powered off, satellites can be found and tracked due to
pre-positioning information (slightly slower) or without information at all (significantly slower).
Additionally to these strategic changes, the search engine does not use all resources available in the search
engine, saving computational load and therefore reducing power consumption, but increasing mean time to
find the satellites.
SBAS Configuration Settings Description
SBAS (Satellite Based Augmentation Systems)
SBAS (Satellite Based Augmentation System) is an augmentation technology for GPS, which calculates GPS
integrity and correction data with RIMS (Ranging and Integrity Monitoring Stations) on the ground and uses
geostationary satellites (GEOs) to broadcast GPS integrity and correction data to GPS users. The correction data
is transmitted on the GPS L1 frequency (1575.42 MHz), and therefore no additional receiver is required to
make use of the correction- and integrity data.
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SBAS Principle
There are several compatible SBAS systems available or in development all around the world:
• WAAS (Wide Area Augmentation System) for North America has been in operation since 2003.
• MSAS (Multi-Functional Satellite Augmentation System) for Asia has been in operation since 2007.
•EGNOS (European Geostationary Navigation Overlay Service) is in test mode ESTB (EGNOS satellite test bed).
EGNOS has passed the ORR (Operational Readiness Review) in Q2/2005. Full operation of EGNOS is planned
for 2008.
•GAGAN (GPS Aided Geo Augmented Navigation), developed by the Indian government is in test mode and
expected to be operational by 2010.
Other systems are planned for Canada (CSAS), Africa (EGNOS) and South America.
SBAS support allows u-blox 5 technology to take full advantage of the augmentation systems that are currently
available (WAAS, EGNOS, MSAS), as well as those being tested and planned (such as GAGAN).
With SBAS enabled the user benefits from additional satellites for ranging (navigation). u-blox 5 technology
uses the available SBAS Satellites for navigation just like GPS satellites, if the SBAS satellites offer this service.
To improve position accuracy SBAS uses different types of correction data:
•Fast Corrections for short-term disturbances in GPS signals (due to clock problems, etc).
•Long-term corrections for GPS clock problems, broadcast orbit errors etc.
•Ionosphere corrections for Ionosphere activity
Another benefit is the use of GPS integrity information. In this way SBAS Control stations can ‘disable’ usage of
GPS satellites in case of major GPS satellite problems within a 6 second alarm time. If integrity monitoring is
enabled, u-blox 5 GPS technology will only use satellites, for which integrity information is available.
For more information on SBAS and associated services please refer to
• RTCA/DO-229C (MOPS). Available from www.rtca.org
•gps.faa.gov for information on WAAS and the NSTB
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•www.esa.int for information on EGNOS and the ESTB
•www.essp.be for information about European Satellite Services Provider EEIG is the EGNOS operations
manager.
•www.kasc.go.jp for information on MSAS
SBAS GEO PRN Numbers
GEO identification Stationed over GPS PRN SBAS Provider
Inmarsat AOR-E Eastern Africa 120 EGNOS
Inmarsat AOR-W Western Africa 122 WAAS
ESA Artemis Africa (Congo) 124 EGNOS
Inmarsat IND-W Africa (Congo) 126 EGNOS
Insat-NAV (tbd) 127 GAGAN
Insat-NAV (tbd) 128 GAGAN
MTSAT-1R (or MTSAT-2) Pacific 129 MSAS
Inmarsat IOR Indian Ocean 131 EGNOS
Inmarsat POR Pacific 134 WAAS
PanAmSat Galaxy XV 133° West 135 WAAS
MTSAT-2 (or MTSAT-1R) (tbd) 137 MSAS
Telesat Anik F1R 107° West 138 WAAS
SBAS Features
This u-blox 5 SBAS implementation is, in accordance with standard RTCA/DO-229C, a class Beta-1
equipment. All timeouts etc. are chosen for the En Route Case. Do not use this equipment under
any circumstances for safety of life applications!
u-blox 5 is capable of receiving multiple SBAS satellites in parallel, even from different SBAS systems (WAAS,
EGNOS, MSAS, etc.). They can be tracked and used for navigation simultaneously. At least three SBAS satellites
can be tracked in parallel. Every SBAS satellite tracked utilizes one vacant GPS receiver tracking channel. Only
the number of receiver channels limits the total number of satellites used. Each SBAS satellite, which broadcasts
ephemeris or almanac information, can be used for navigation, just like a normal GPS satellite.
For receiving correction data, the u-blox 5 GPS receiver automatically chooses the best SBAS satellite as its
primary source. It will select only one since the information received from other SBAS GEOs is redundant and/or
could be inconsistent. The selection strategy is determined by the proximity of the GEOs, the services offered by
the GEO, the configuration of the receiver (Testmode allowed/disallowed, Integrity enabled/disabled) and the
signal link quality to the GEO.
In case corrections are available from the chosen GEO and used in the navigation calculation, the DGPS flag is
set in the receiver’s output protocol messages (see NAV-SOL, NAV-STATUS, NAV-SVINFO, NMEA Position
Fix Flags description).
The most important SBAS feature for accuracy improvement is Ionosphere correction. The measured data from
RIMS stations of a region are combined to a TEC (Total Electron Content) Map. This map is transferred to the
GPS devices via the GEOs to allow a correction of the ionosphere error on each received satellite.
Supported SBAS messages
Message Type Message Content Used from GEO
0(0/2) Test Mode All
1 PRN Mask Assignment Primary
2, 3, 4, 5 Fast Corrections Primary
6 Integrity Primary
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Supported SBAS messages continued
Message Type Message Content Used from GEO
7 Fast Correction Degradation Primary
9 GEO Navigation (Ephemeris) All
10 Degradation Primary
12 Time Offset Primary
17 GEO Almanacs All
18 Ionosphere Grid Point Assignment Primary
24 Mixed Fast / Long term Corrections Primary
25 Long term Corrections Primary
26 Ionosphere Delays Primary
As each GEO services a specific region, the correction signal is only useful within that region. Therefore, mission
planning is crucial to determine the best possible configuration. The different stages (Testmode vs. Operational)
of the various SBAS systems further complicate this task. The following examples show possible scenarios:
Example 1: SBAS Receiver in North America
At the time of writing, the WAAS system is in operational stage, whereas the EGNOS system is still in test mode
(ESTB). Therefore, and especially in the eastern parts of the US, care must be taken in order not to have EGNOS
satellites taking preference over WAAS satellites. This can be achieved by disallowing Test Mode use (this
inhibits EGNOS satellites from being used as a correction data source), but keeping the PRN Mask to have all
SBAS GEOs enabled (which allows EGNOS GEOs to be used for navigation).
Example 2: SBAS Receiver in Europe
At the time of writing, the EGNOS system is still in test mode. To try out EGNOS operation, Testmode usage
must be enabled. Since the WAAS GEO #122 can be received in the western parts of Europe, but since this
GEO does not carry correction data for the European continent, the GEOs from all but the EGNOS system
should be disallowed, using the PRN Mask. It is important to understand that while EGNOS is in test mode,
anything can happen to the EGNOS signals, such as sudden interruption of service or broadcast of invalid or
inconsistent data.
The u-blox 5 GPS receiver always makes use of the best available SBAS correction data.
SBAS Configuration
To configure the SBAS functionalities use the UBX proprietary message UBX–CFG–SBAS (SBAS
Configuration).
SBAS Configuration parameters
Parameter Description
Mode - SBAS Subsystem Enables or disables the SBAS subsystem
Mode - Allow test mode usage Allow / Disallow SBAS usage from satellites in Test Mode (Message 0)
Services/Usage - Ranging Use the SBAS satellites for navigation
Services/Usage - Apply SBAS
correction data
Combined enable/disable switch for Fast-, Long-Term and Ionosphere
Corrections
Services/Usage - Apply integrity
information
Use integrity data
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SBAS Configuration parameters continued
Parameter Description
Number of tracking channels Sets how many channels are reserved for SBAS tracking (if that many
SBAS signals were acquired). E.g., if this is set to three and five SBAS
SVs are acquired, only three of them will prioritized over available GPS
signals.
PRN Mask Allows to selectively enable/disable SBAS satellite. With this parameter,
for example, one can restrict SBAS usage to WAAS-only
By default SBAS is enabled with three prioritized SBAS channels and it will use any received SBAS satellites
(except for those in test mode) for navigation, ionosphere parameters and corrections.
NMEA Protocol Configuration
The NMEA protocol on u-blox receivers can be configured to the need of customer applications using
CFG-NMEA. As default all invalid positions out of the defined accuracy range are not reported.
There are two NMEA standards supported. The default NMEA protocol version is 2.3. Alternatively also
Specification version 2.1 can be enabled (for details on how this affect the output refer to section Position Fix
Flags in NMEA Mode ).
NMEA filtering flags
Parameter Description
Position filtering If disabled, invalid or old position output is being communicated, but the valid flag
indicates that the data is not current.
Masked position
filtering
If disabled, Masked position data is still being output, but the valid flag will indicate that
the defined accuracy range has been exceeded.
Time filtering If disabled, the receiver's best knowledge of time is output, even though it might be
wrong.
Date filtering If disabled, the receiver's best knowledge of date is output, even though it might be
wrong.
SBAS filtering If enabled, SBAS satellites are reported according to the NMEA standard.
Track filtering If disabled, an unfiltered course over ground (COG) output is being output.
NMEA flags
Parameter Description
Compatibility Mode Some NMEA applications only work with a fixed number of digits behind the decimal
comma. Therefore u-blox receivers offer a compatibility mode to communicate with the
most popular map applications.
Consideration Mode u-blox receivers use a sophisticated signal quality detection scheme, in order to produce
the best possible position output. This algorithm considers all SV measurements, and
eventually decides to only use a subset thereof, if it improves the overall position
accuracy. If Consideration mode is enabled, all Satellites, which were considered for
navigation, are being communicated as being used for the position determination. If
Consideration Mode is disabled, only those satellites are marked as being used, which
after the consideration step remained in the position output.
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Time Mode Configuration
Introduction
Time Mode is a special stationary GPS receiver mode where the position of the receiver is known and fixed and
only the time is calculated using all available satellites. This mode allows for maximum time accuracy as well as
for single-SV solutions.
Fixed Position
In order to use the Time Mode, the receiver's position must be known as exactly as possible. Either the user
already knows and enters the position, or it is determined using a Survey-in. Errors in the fixed position will
translate into time errors depending on the satellite constellation. Using the TDOP value (see UBX-NAV-DOP)
and assuming a symmetrical 3D position error , the expected time error can be estimated as
time error = tdop * position error
As a rule of thumb the position should be known better than 1m for a time accuracy on the order of
nanoseconds. If only microseconds accuracy is required, a position accuracy of roughly 300m is sufficient.
Survey-in
Survey-in is the procedure of determining a stationary receiver's position prior to using Time Mode by
averaging. The current implementation builds a weighted mean of all valid 3D position solutions. Two stop
criteria can be specified:
•The minimum observation time defines a minimum amount of observation time regardless of the actual
number of valid fixes that were used for the position calculation. Reasonable values range from one day for
high accuracy requirements to a few minutes for coarse position determination.
•The required 3D position standard deviation forces the calculated position to be of at least the given
accuracy. As the position error translates into a time error when using Time Mode (see above), one should
carefully evaluate the time accuracy requirements and the choose an appropriate position accuracy
requirement.
Survey-In ends, when both requirements are met. After Survey-In has finished successfully, the receiver will
automatically enter fixed position Time Mode. The Survey-In status can queried using the UBX-TIM-SVIN
message.
Navigation Configuration Settings Description
Platform settings
u-blox 5 positioning technology supports different dynamic platform models to adjust the navigation engine to
the expected environment. These platform settings can be changed dynamically without doing a power cycle or
reset. It allows a better interpretation of the measurements and hence provides a more accurate position
output. Setting the receiver to an unsuitable platform model for the application environment may reduce the
receiver performance and position accuracy significantly.
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Dynamic Platform Model
Platform Description
Portable Default setting. Applications with low accelerations, as any portable devices. Suitable for
most situations.
Stationary Used in timing applications (antenna must be stationary) or other stationary applications.
Velocity is constrained to 0 m/s. Zero dynamics assumed.
Pedestrian Applications with low accelerations and low speed, as a pedestrian would move. Assuming
low accelerations.
Automotive Used for applications that can be compared with the dynamics of a passenger car.
Assuming low vertical acceleration.
At sea Recommended for applications at sea, with zero vertical velocity. Assuming zero vertical
velocity.
Airborne <1g Used for applications that have to handle a higher dynamic range than a car and higher
vertical accelerations. No 2D position fixes supported.
Airborne <2g Recommended for typical airborne environment. No 2D position fixes supported.
Airborne <4g Only recommended for an extreme dynamic environment. No 2D position fixes supported.
Dynamic platforms designed for high acceleration systems (e.g. airborne <2g) may result in a
greater standard deviation in the reported position.
Navigation Input Filters
The navigation input filters mask the input data of the navigation engine.
These settings are already optimized. It is not recommended that changes to any parameters be
made unless advised by u-blox support engineers.
Navigation Input Filter parameters
Parameter Description
fixMode By default, the receiver calculates a 3D position fix if possible but reverts to a 2D position if
necessary (Auto 2D/3D). It is possible to force the receiver to permanently calculate 2D (2D
only) or 3D (3D only) positions.
fixedAlt and
fixedAltVar
The fixed altitude is used if fixMode is set to 2D only. A variance greater than zero must be
supplied as well.
minElev Minimum elevation of a satellite above the horizon in order to be used in the navigation
solution. Low elevation satellites may provide degraded accuracy, because of the long
signal path through the atmosphere.
drLimit Dead Reckoning limit: The time during which the receiver provides an extrapolated
solution. After the DR timeout has expired, no GPS solution is provided at all.
Navigation Output Filters
The navigation output filters adjust the valid flag of the relevant NMEA and UBX output messages. Users of the
UBX protocol have additional access to messages containing an accuracy indicator, along with the position,
time and velocity solutions.
•The pDop and pAcc values: The PDOP and Position Accuracy Mask are used to determine if a position
solution is marked valid in the NMEA sentences or if the UBX PosLimit flag is set. A solution is considered
valid, when both PDOP and Accuracy lie below the respective limits.
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•The tDop and tAcc values: The TDOP and Time Accuracy Mask are used to determine when a time pulse
should be allowed. The time pulse is disabled if either TDOP or the time accuracy exceeds its respective limit.
See also the TIM-TP message description.
Static Hold
The Static Hold mode allows the navigation algorithms to decrease the noise in the position output when the
velocity is below a pre-defined ‘Static Hold Threshold’. This reduces the position wander caused by
environmental issues such as multi-path and improves position accuracy especially in stationary applications. By
default, static hold mode is disabled.
If the speed goes below the defined ‘Static Hold Threshold’, the position is kept constant. Once the static hold
mode has been entered, the position and velocity output will be kept constant, until there is evidence of
movement. Such evidence can be velocity, acceleration, changes of the valid flag (e.g. position accuracy
estimate exceeding the Position Accuracy Mask, see also section Navigation Output Filters), position
displacement, etc.
Degraded Navigation
Degraded navigation describes all navigation modes, which use less than 4 satellites.
2D Navigation
If the receiver only has 3 satellites to calculate a position, the navigation algorithm uses a constant altitude to
make up for the missing fourth satellite. When losing a satellite after a successful 3D fix (min. 4 SV available),
the altitude is kept constant to the last known altitude. This is called a 2D fix.
The u-blox 5 positioning technology does not calculate any solution with a number of SVs less than
3. Only u-blox 5 Timing Receivers can calculate timing solution with only one SV when stationary.
Dead Reckoning, Extrapolating Positioning
The implemented extrapolation algorithm kicks in as soon as the receiver no longer achieves a position fix with
a sufficient position accuracy or DOP value (see section Navigation Output Filters). It keeps a fix track (heading
is equal to the last calculated heading) until the Dead Reckoning Timeout is reached. The position is
extrapolated but it’s indicated as “NoFix” (except for NMEA V2.1).
For sensor based Dead Reckoning GPS solutions, u-blox offers Dead Reckoning enabled GPS modules. They
allow high accuracy position solutions for automotive applications at places with poor or no GPS coverage. This
technology relies on additional inputs like a turn rate sensor (gyro) or a speed sensor (odometer or wheel tick).
Receiver Status Monitoring
Messages in this class are used to report the status of the non-GPS-specific parts of the embedded computer
system.
The main purposes are
• Stack- and CPU load (Antaris 4, only)
• Hard- and Software Versions, using MON-VER
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• Status of the Communications Input/Output system
• Status of various Hardware Sections with MON-HW
Input/Output system
The I/O system is a GPS-internal layer where all data input- and output capabilities (such as UART, DDC, SPI,
USB) of the GPS receiver are combined. Each communications task has buffers assigned, where data is queued.
For data originating at the receiver, to be communicated over one or multiple communications queues, the
message MON-TXBUF can be used. This message shows the current and maximum buffer usage, as well as
error conditions.
If too much data is being configured for a certain port's bandwidth (e.g. all UBX messages shall be
output on a UART port with a baud rate of 9600), the buffer will fill up. Once the buffer's space is
exceeded, the receiver will deactivate messages automatically.
Inbound data to the GPS receiver is placed in buffers. These buffers' usage are shown with the message
MON-RXBUF. Further, as data is then decoded within the receiver (e.g. to separate UBX- and NMEA data), the
MON-MSGPP can be used. This message shows, for each port and protocol, how many messages were
successfully received. It also shows, for each port, how many bytes were discarded because they were not in
any of the supported protocol framings.
A target in the context of the I/O system is a I/O protocol. The following table shows the target numbers
used
Target Number assignment
Target # Electrical Interface
0 DDC (I2C compatible)
1 UART 1
2 UART 2
3 USB
4 SPI
5 reserved
Protocol Number assignment
Protocol # Protocol Name
0 UBX Protocol
1 NMEA Protocol
2 RTCM Protocol (not supported on u-blox 5)
3 RAW Protocol (not supported on u-blox 5)
4..7 Reserved for future use
Aiding
Introduction
The UBX Message Class AID provides all mechanisms for providing Assiste GPS Data to u-blox GPS receivers,
including AssistNow Online and AssistNow Offline.
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Aiding Data
Following aiding data can be submitted to the receiver:
•Position Position information can be submitted to the receiver using the UBX-AID-INI message. Both,
ECEF X/Y/Z and latitude/longitude/height formats are supported.
•Time The time can either be supplied as an inexact value via the standard communication interfaces,
suffering from latency depending on the baud rate, or using hardware time synchronization where an
accurate time pulse is connected to an external interrupt. Both methods are supported in the UBX-AID-INI
message.
•Frequency It is possible to supply hardware frequency aiding by connecting a continuous signal to an
external interrupt using the UBX-AID-INI message.
•Orbit data Orbit data can be submitted using UBX-AID-ALM and UBX-AID-EPH.
•Additional information UBX-AID-HUI can be used to supply health information, UTC parameters and
ionospheric data to the receiver.
Aiding Sequence
A typical aiding sequence would comprise following steps:
• Power-up the GPS receiver
• Send UBX-AID-INI (time, clock and position) message.
• Send UBX-AID-EPH (ephemeris) message.
•Apply optional hardware time synchronization pulse within 0.5s after (or before, depending on the
configuration in UBX-AID-INI) sending the UBX-AID-INI message if hardware time synchronization is
required. When sending the message before applying the pulse, make sure to allow the GPS receiver to
parse and process the aiding message. The time for parsing depends on the baud rate. The processing time
is 100ms maximum.
• Send optional UBX-AID-HUI (health, UTC and ionosphere parameters) message.
• Send optional UBX-AID-ALM (almanac) message.
AssistNow Online
AssistNow Online is u-blox' end-to-end Assisted GPS (A-GPS) solution that boosts GPS acquisition performance,
bringing Time To First Fix (TTFF) down to seconds. The system works by accessing assistance data such as
Ephemeris, Almanac and accurate time from our Global Reference Network of globally placed GPS receivers.
With A-GPS, the receiver can acquire satellites and provide accurate position data instantly on demand, even
under poor signal conditions.
AssistNow Online makes use of User Plane communication and open standards such as TCP/IP. Therefore, it
works on all standard mobile communication networks that support Internet access, including GPRS, UMTS and
Wireless LAN. No special arrangements need to be made with mobile network operators to enable AssistNow
Online.
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Messaging wise, AssistNow Online consists of Aiding data which deliver Position and Time UBX-AID-INI,
Ephemerides UBX-AID-EPH, Almanac UBX-AID-ALM and Health/UTC/Iono information UBX-AID-HUI
AssistNow Offline
AssistNow Offline is an A-GPS service that boosts GPS acquisition performance, bringing Time To First Fix (TTFF)
down to seconds. Unlike AssistNow Online, this solution enables instant positioning without the need for
connectivity at start-up. The system works by using AlmanacPlus (ALP) differential almanac correction data to
speed up acquisition, enabling a position fix within seconds. Users access the data by means of occasional
Internet downloads, at the user's convenience.
u-blox provides AlmanacPlus data files in different sizes, which contain differential almanac corrections that are
valid for a period of between 1 and 14 days thereafter. Users can download correction data anytime they have
an Internet connection. The GPS receiver stores the downloaded data in the non-volatile Flash EPROM. As an
alternative, a host CPU may store the file, but deliver the data in pieces when requested.
AssistNow Offline works in locations without any wireless connectivity as the correction data files reside in the
receiver or the host. This makes them immediately available upon start-up, eliminating connection set-up
delays, download waiting times and call charges.
The simplest set-up is for GPS receivers including an internal Flash Memory where ALP data can be stored. In
this case, the UBX-AID-ALP message is used.
When the GPS receiver does not contain a Flash Memory, the ALP file must be stored to the host CPU. The GPS
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receiver can the request data from the host when needed. This arrangement is implemented using the
UBX-AID-ALPSRV message.
In both cases, status reporting on ALP data currently available to the GPS receiver can be taken from message
AID-ALP_STAT
AssistNow Offline data are published at http://alp.u-blox.com
Please note that this functionality is only supported on u-blox 5 Firmware 4.0 and above.
Host-based AlmanacPlus Overview
All three versions of AID-ALPSRV messages are used for the case where the storage of an ALP file is not within
the receiver's Flash memory, but on the host, and where the host needs to deliver data to the GPS receiver
repeatedly. This allows support of the AlmanacPlus functionality for GPS receivers which do not have a Flash
memory. For messaging details of an implementation where the data is to reside in the receiver's Flash
memory, see UBX-AID-ALP-DESC
In the following, the GPS receiver is called the client, as it primarily requests data, and the host CPU where the
ALP file is located in its entirety is called the server.
The operation is such that the client sends periodic data requests (the ALP client requests ALPSRV-REQ ) to the
host, and the host should answer them accordingly, as described below at ALPSRV-SRV
For this mechanism to work, the AID-ALPSRV message needs to be activated using the normal
CFG-MSG commands. If it is not activated, no requests are sent out.
The client may attempt to modify the data which is stored on the server, using the ALPSRV-CLI message. The
server may safely ignore such a request, in case the ALP file can not be modified. However, for improved
performance for consecutive receiver restarts, it is recommended to modify the data.
Overview of the three versions of AID-ALPSRV messages
Short Name Content Direction
ALPSRV-REQ ALP client requests AlmanacPlus data from server Client -> Server
ALPSRV-SRV ALP server sends AlmanacPlus data to client Server -> Client
ALPSRV-CLI ALP client sends AlmanacPlus data to server. Client -> Server
Message specifics
The three variants of this message always have a header and variable-size data appended within the same
message. The very first field, idSize gives the number of bytes where the header within the UBX payload
ends and data starts.
In case of the ALP client request, the server must assemble a new message according to the
AID-ALPSRV-SRV variant. The header needs to be duplicated for as many as idSize bytes. Additionally, the
server needs to fill in the fileId and dataSize fields. Appended to the idSize-sized header, data must be
added as requested by the client (from offset ofs, for size number of values).
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Range checks
The server needs to perform an out-of-bounds check on the ofs and size fields, as the client may request
data beyond the actually available data. If the client request is within the bounds of available data, the
dataSize field needs to be filled in with 2 x the content of the size field (the size field is in units of 16 bits,
whereas the dataSize field expects number of bytes). If the client request would request data beyond the
limits of the buffer, the data should be reduced accordingly, and this actual number of bytes sent shall be
indicated in the dataSize field
Changing ALP files
The server function would periodically attempt to receive new ALP data from an upstream server, as the result
of an HTTP request or other means of file transfer.
In case a new file becomes available, then the server shall indicate this to the Client. This is the function of the
fileId field.
The server should number ALP files it serves arbitrarily. The only requirement is that the fileId actually is
changed when a new file is being served, and that it does not change as long as the same file is being
changed.
If the client, as a result of a client request, receives a fileId different from the one in earlier requests' replies, it
will reinitialize the ALP engine and request data anew.
Further, if the client attempts to send data to the server, using the ALPSRV-CLI method, it indicates, which
fileId needs to be written. The server shall ignore that request in case the fileId numbers do not match.
Sample Code
u-blox makes available sample code, written in C language, showing a server implementation, serving ALP data
from its file system to a client. Please contact your nearest u-blox Field Application engineer to receive a copy.
Please note that this functionality is only supported on u-blox 5 Firmware 4.0 and above and with
special versions of Antaris 4 receivers.
Flash-based AlmanacPlus Overview
Flash-based AlmanacPlus functionality means that AlmanacPlus data is stored in the program flash memory
connected to the u-blox 5 chip. The task of a server is simply to download the data from an Internet server or
other sources, and then deliver the full file piece by piece to the GPS receiver. This is different to the method
described in UBX-AID-ALPSRV where the file would remain within the host and the GPS receiver would request
chunks from that file when needed.
The message AID-ALP exists in several variants, combining all functionality needed to download data and report
status within one Class/Message ID.
Download Procedure
The following steps are a typical sequence for downloading an ALP file to the receiver:
• The server downloads a copy of a current ALP file, and stores it locally
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• It sends the first N bytes from that file, using the AID-ALP-TX message
• The server awaits a AID-ALP-ACK or AID-ALP-NAK message.
• If can then continue, sending the next N bytes if the message was acknowledged.
•Once all data has been transferred, or a NAK has been received, the server sends an AID-ALP-STOP
message
Please note that
•N should not be larger than ~700 bytes (due to the input buffers on the RS232/USB lines). Smaller values of
N might improve reliability
•N must be a multiple of 2.
•There is no re-send mechanism. If a NAK message is received, the full downloading process must be
restarted.
•There is no explicit checksum, but an implicit one, as the ALP file already includes a checksum to verify
consistency
Overview of the different versions of AID-ALP messages
Short Name Content Direction
AID-ALP-TX ALP server sends Data to client Server -> Client
AID-ALP-STOP ALP server terminates a transfer sequence Server -> Client
AID-ALP-ACK ALP client acknowledges successful receipt of data. Client -> Server
AID-ALP-NAK ALP client indicates a failed reception of data Client -> Server
AID-ALP-STAT ALP client reports status of the ALP data stored in flash memory Client -> Server
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NMEA Protocol
Protocol Overview
NMEA messages sent by the GPS receiver are based on NMEA 0183 Version 2.3. The following picture shows
the structure of a NMEA protocol message.
For further information on the NMEA Standard please refer to NMEA 0183 Standard For Interfacing Marine
Electronic Devices, Version 2.30, March 1, 1998. See http://www.nmea.org/ for ordering instructions.
The NMEA standard allows for proprietary, manufacturer-specific messages to be added. These shall be marked
with a manufacturer mnemonic. The mnemonic assigned to u-blox is UBX and is used for all non-standard
messages. These proprietary NMEA messages therefore have the address field set to PUBX. The first data field
in a PUBX message identifies the message number with two digits.
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Latitude and Longitude Format
According to the NMEA Standard, Latitude and Longitude are output in the format Degrees, Minutes and
(Decimal) Fractions of Minutes. To convert to Degrees and Fractions of Degrees, or Degrees, Minutes, Seconds
and Fractions of seconds, the 'Minutes' and 'Fractional Minutes' parts need to be converted. In other words: If
the GPS Receiver reports a Latitude of 4717.112671 North and Longitude of 00833.914843 East, this is
Latitude 47 Degrees, 17.112671 Minutes
Longitude 8 Degrees, 33.914843 Minutes
or
Latitude 47 Degrees, 17 Minutes, 6.76026 Seconds
Longitude 8 Degrees, 33 Minutes, 54.89058 Seconds
or
Latitude 47.28521118 Degrees
Longitude 8.56524738 Degrees
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Position Fix Flags in NMEA Mode
The following list shows how u-blox implements the NMEA protocol, and the conditions determining how flags
are set in version 2.3 and above.
NMEA Message: Field No position fix (at
power-up, after
losing satellite lock)
Valid position fix,
but user limits
exceeded
Dead reckoning
(linear
extrapolation)
EKF (only on DR
receivers)
2D position fix 3D position fix combined GPS/EKF
position fix (only on DR
receivers)
GLL, RMC: Status V V V A A A A
A=Data VALID, V=Data Invalid (Navigation Receiver Warning)
GGA: Quality Indicator 0 0 6 6 1 / 2 1 / 2 1 / 2
0=Fix not available/invalid, 1=GPS SPS Mode, Fix valid, 2=Differential GPS, SPS Mode, Fix Valid, 6=Estimated/Dead Reckoning
GSA: Nav Mode 1 1 2 2 2 3 3
1=Fix Not available, 2=2D Fix, 3=3D Fix
GLL, RMC, VTG: Mode
Indicator
N N E E A / D A / D A / D
N=No Fix, A=Autonomous GNSS Fix, D=Differential GNSS Fix, E=Estimated/Dead Reckoning Fix
UBX GPSFixOK 0 0 0 1 1 1 1
UBX GPSFix 0 >1 1 1 2 3 4
The following list shows how u-blox implements the NMEA protocol, and the conditions determining how flags
are set in version 2.2 and below.
NMEA Message: Field No position fix (at
power-up, after
losing satellite lock
Valid position fix,
but user limits
exceeded
Dead reckoning
(linear
extrapolation)
EKF (only on DR
receivers)
2D position fix 3D position fix combined GPS/EKF
position fix (only on DR
receivers)
GLL, RMC: Status V V A A A A A
A=Data VALID, V=Data Invalid (Navigation Receiver Warning)
GGA: Quality Indicator 0 0 1 1 1 / 2 1 / 2 1 / 2
0=Fix not available/invalid, 1=GPS SPS Mode, Fix valid, 2=Differential GPS, SPS Mode, Fix Valid
GSA: Nav Mode 1 1 2 2 2 3 3
1=Fix Not available, 2=2D Fix, 3=3D Fix
GLL, RMC, VTG: Mode Indicator. This field is not output by this NMEA version.
UBX GPSFixOK 0 0 0 1 1 1 1
UBX GPSFix 0 >1 1 1 2 3 4
By default the receiver will not output invalid data. In such cases, it will output empty fields.
• A valid position fix is reported as follows:
$GPGLL,4717.11634,N,00833.91297,E,124923.00,A,A*6E
• An invalid position fix (but time valid) is reported as follows:
$GPGLL,,,,,124924.00,V,N*42
• If Time is unknown (e.g. during a cold-start):
$GPGLL,,,,,,V,N*64
In Antaris firmware versions older than 3.0, the receiver did output invalid data and marked it with
the 'Invalid/Valid' Flags. If required, this function can still be enabled in later firmware versions,
using the UBX protocol message CFG-NMEA.
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NMEA Messages Overview
When configuring NMEA messages using the UBX protocol message CFG-MSG, the Class/Ids shown in the
table shall be used.
Page Mnemonic Cls/ID Description
NMEA Proprietary Messages Proprietary Messages
52 UBX,00 0xF1 0x00 Lat/Long Position Data
54 UBX,03 0xF1 0x03 Satellite Status
56 UBX,04 0xF1 0x04 Time of Day and Clock Information
58 UBX,40 0xF1 0x40 Set NMEA message output rate
59 UBX,41 0xF1 0x41 Set Protocols and Baudrate
57 UBX 0xF1 0x40 Poll a PUBX message
NMEA Standard Messages Standard Messages
49 DTM 0xF0 0x0A Datum Reference
48 GBS 0xF0 0x09 GNSS Satellite Fault Detection
38 GGA 0xF0 0x00 Global positioning system fix data
40 GLL 0xF0 0x01 Latitude and longitude, with time of position fix and status
50 GPQ 0xF0 0x40 Poll message
45 GRS 0xF0 0x06 GNSS Range Residuals
41 GSA 0xF0 0x02 GPS DOP and Active Satellites
46 GST 0xF0 0x07 GNSS Pseudo Range Error Statistics
42 GSV 0xF0 0x03 GPS Satellites in View
43 RMC 0xF0 0x04 Recommended Minimum data
51 TXT 0xF0 0x41 Text Transmission
44 VTG 0xF0 0x05 Course over ground and Ground speed
47 ZDA 0xF0 0x08 Time and Date
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Standard Messages
Standard Messages : i.e. Messages as defined in the NMEA Standard.
GGA
Message GGA
Description Global positioning system fix data
Type Output Message
Comment The output of this message is dependent on the currently selected datum (Default:
WGS84)
Time and position, together with GPS fixing related data (number of satellites in use, and
the resulting HDOP, age of differential data if in use, etc.).
ID for CFG-MSG Number of fields
Message Info 0xF0 0x00 17
Message Structure:
$GPGGA,hhmmss.ss,Latitude,N,Longitude,E,FS,NoSV,HDOP,msl,m,Altref,m,DiffAge,DiffStation*cs<CR><LF>
Example:
$GPGGA,092725.00,4717.11399,N,00833.91590,E,1,8,1.01,499.6,M,48.0,M,,0*5B
Field
No.
Example Format Name Unit Description
0 $GPGGA string $GPGGA - Message ID, GGA protocol header
1 092725.00 hhmmss.sss hhmmss.
ss
- UTC Time, Current time
2 4717.11399 ddmm.mmmm Latitude - Latitude, Degrees + minutes, see Format description
3 N character N- N/S Indicator, N=north or S=south
4 00833.91590 dddmm.
mmmm
Longitud
e
- Longitude, Degrees + minutes, see Format
description
5 E character E- E/W indicator, E=east or W=west
6 1 digit FS - Position Fix Status Indicator, See Table below and
Position Fix Flags description
7 8 numeric NoSV - Satellites Used, Range 0 to 12
8 1.01 numeric HDOP - HDOP, Horizontal Dilution of Precision
9 499.6 numeric msl m MSL Altitude
10 M character uMsl - Units, Meters (fixed field)
11 48.0 numeric Altref m Geoid Separation
12 M character uSep - Units, Meters (fixed field)
13 - numeric DiffAge s Age of Differential Corrections, Blank (Null) fields
when DGPS is not used
14 0 numeric DiffStat
ion
- Diff. Reference Station ID
15 *5B hexadecimal cs - Checksum
16 - character <CR><LF> - Carriage Return and Line Feed
NMEA, UBX Protocol Specification, u-blox 5 GNSS Receiver
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NMEA Protocol
Page 38
Table Fix Status
Fix Status Description, see also Position Fix Flags description
0 No Fix / Invalid
1 Standard GPS (2D/3D)
2 Differential GPS
6 Estimated (DR) Fix
NMEA, UBX Protocol Specification, u-blox 5 GNSS Receiver
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NMEA Protocol
Page 39
GLL
Message GLL
Description Latitude and longitude, with time of position fix and status
Type Output Message
Comment The output of this message is dependent on the currently selected datum (Default:
WGS84)
-
ID for CFG-MSG Number of fields
Message Info 0xF0 0x01 (9) or (10)
Message Structure:
$GPGLL,Latitude,N,Longitude,E,hhmmss.ss,Valid,Mode*cs<CR><LF>
Example:
$GPGLL,4717.11364,N,00833.91565,E,092321.00,A,A*60
Field
No.
Example Format Name Unit Description
0 $GPGLL string $GPGLL - Message ID, GLL protocol header
1 4717.11364 ddmm.mmmm Latitude - Latitude, Degrees + minutes, see Format description
2 N character N- N/S Indicator, hemisphere N=north or S=south
3 00833.91565 dddmm.
mmmm
Longitud
e
- Longitude, Degrees + minutes, see Format
description
4 E character E- E/W indicator, E=east or W=west
5 092321.00 hhmmss.sss hhmmss.
ss
- UTC Time, Current time
6 A character Valid - V = Data invalid or receiver warning, A = Data valid.
See Position Fix Flags description
Start of optional block
7 A character Mode - Positioning Mode, see Position Fix Flags description
End of optional block
7 *60 hexadecimal cs - Checksum
8 - character <CR><LF> - Carriage Return and Line Feed
NMEA, UBX Protocol Specification, u-blox 5 GNSS Receiver
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NMEA Protocol
Page 40
GSA
Message GSA
Description GPS DOP and Active Satellites
Type Output Message
Comment •If less than 12 SVs are used for navigation, the remaining fields are left empty. If more
than 12 SVs are used for navigation, only the IDs of the first 12 are output.
•The SV Numbers (Fields 'Sv') are in the range of 1 to 32 for GPS satellites, and 33 to 64
for SBAS satellites (33 = SBAS PRN 120, 34 = SBAS PRN 121, and so on)
ID for CFG-MSG Number of fields
Message Info 0xF0 0x02 20
Message Structure:
$GPGSA,Smode,FS{,sv},PDOP,HDOP,VDOP*cs<CR><LF>
Example:
$GPGSA,A,3,23,29,07,08,09,18,26,28,,,,,1.94,1.18,1.54*0D
Field
No.
Example Format Name Unit Description
0 $GPGSA string $GPGSA - Message ID, GSA protocol header
1 A character Smode - Smode, see first table below
2 3 digit FS - Fix status, see second table below and Position Fix
Flags description
Start of repeated block (12 times)
3 +
1*N
29 numeric sv - Satellite number
End of repeated block
15 1.94 numeric PDOP - Position dilution of precision
16 1.18 numeric HDOP - Horizontal dilution of precision
17 1.54 numeric VDOP - Vertical dilution of precision
18 *0D hexadecimal cs - Checksum
19 - character <CR><LF> - Carriage Return and Line Feed
Table Smode
Smode Description
M Manual - forced to operate in 2D or 3D mode
A Allowed to automatically switch 2D/3D mode
Table Fix Status
Fix Status Description, see also Position Fix Flags description
1 Fix not available
2 2D Fix
3 3D Fix
NMEA, UBX Protocol Specification, u-blox 5 GNSS Receiver
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NMEA Protocol
Page 41
GSV
Message GSV
Description GPS Satellites in View
Type Output Message
Comment The number of satellites in view, together with each PRN (SV ID), elevation and azimuth,
and C/No (Signal/Noise Ratio) value. Only four satellite details are transmitted in one
message. There are up to 4 messages used as indicated in the first field NoMsg.
ID for CFG-MSG Number of fields
Message Info 0xF0 0x03 7..16
Message Structure:
$GPGSV,NoMsg,MsgNo,NoSv,{,sv,elv,az,cno}*cs<CR><LF>
Example:
$GPGSV,3,1,10,23,38,230,44,29,71,156,47,07,29,116,41,08,09,081,36*7F
$GPGSV,3,2,10,10,07,189,,05,05,220,,09,34,274,42,18,25,309,44*72
$GPGSV,3,3,10,26,82,187,47,28,43,056,46*77
Field
No.
Example Format Name Unit Description
0 $GPGSV string $GPGSV - Message ID, GSV protocol header
1 3 digit NoMsg - Number of messages, total number of GPGSV
messages being output
2 1 digit MsgNo - Number of this message
3 10 numeric NoSv - Satellites in View
Start of repeated block (1..4 times)
4 +
4*N
23 numeric sv - Satellite ID
5 +
4*N
38 numeric elv degr
ees
Elevation, range 0..90
6 +
4*N
230 numeric az degr
ees
Azimuth, range 0..359
7 +
4*N
44 numeric cno dBH
z
C/N0, range 0..99, null when not tracking
End of repeated block
5..
16
*7F hexadecimal cs - Checksum
6..
16
- character <CR><LF> - Carriage Return and Line Feed
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NMEA Protocol
Page 42
RMC
Message RMC
Description Recommended Minimum data
Type Output Message
Comment The output of this message is dependent on the currently selected datum (Default:
WGS84)
The Recommended Minimum sentence defined by NMEA for GPS/Transit system data.
ID for CFG-MSG Number of fields
Message Info 0xF0 0x04 15
Message Structure:
$GPRMC,hhmmss,status,latitude,N,longitude,E,spd,cog,ddmmyy,mv,mvE,mode*cs<CR><LF>
Example:
$GPRMC,083559.00,A,4717.11437,N,00833.91522,E,0.004,77.52,091202,,,A*57
Field
No.
Example Format Name Unit Description
0 $GPRMC string $GPRMC - Message ID, RMC protocol header
1 083559.00 hhmmss.sss hhmmss.
ss
- UTC Time, Time of position fix
2 A character Status - Status, V = Navigation receiver warning, A = Data
valid, see Position Fix Flags description
3 4717.11437 ddmm.mmmm Latitude - Latitude, Degrees + minutes, see Format description
4 N character N- N/S Indicator, hemisphere N=north or S=south
5 00833.91522 dddmm.
mmmm
Longitud
e
- Longitude, Degrees + minutes, see Format
description
6 E character E- E/W indicator, E=east or W=west
7 0.004 numeric Spd knot
s
Speed over ground
8 77.52 numeric Cog degr
ees
Course over ground
9 091202 ddmmyy date - Date in day, month, year format
10 - numeric mv degr
ees
Magnetic variation value, not being output by
receiver
11 - character mvE - Magnetic variation E/W indicator, not being output
by receiver
12 - character mode - Mode Indicator, see Position Fix Flags description
13 *57 hexadecimal cs - Checksum
14 - character <CR><LF> - Carriage Return and Line Feed
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Page 43
VTG
Message VTG
Description Course over ground and Ground speed
Type Output Message
Comment Velocity is given as Course over Ground (COG) and Speed over Ground (SOG).
ID for CFG-MSG Number of fields
Message Info 0xF0 0x05 12
Message Structure:
$GPVTG,cogt,T,cogm,M,sog,N,kph,K,mode*cs<CR><LF>
Example:
$GPVTG,77.52,T,,M,0.004,N,0.008,K,A*06
Field
No.
Example Format Name Unit Description
0 $GPVTG string $GPVTG - Message ID, VTG protocol header
1 77.52 numeric cogt degr
ees
Course over ground (true)
2 T character T- Fixed field: true
3 - numeric cogm degr
ees
Course over ground (magnetic), not output
4 M character M- Fixed field: magnetic
5 0.004 numeric sog knot
s
Speed over ground
6 N character N- Fixed field: knots
7 0.008 numeric kph km/
h
Speed over ground
8 K character K- Fixed field: kilometers per hour
9 A character mode - Mode Indicator, see Position Fix Flags description
10 *06 hexadecimal cs - Checksum
11 - character <CR><LF> - Carriage Return and Line Feed
NMEA, UBX Protocol Specification, u-blox 5 GNSS Receiver
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NMEA Protocol
Page 44
GRS
Message GRS
Description GNSS Range Residuals
Type Output Message
Comment This messages relates to associated GGA and GSA messages.
If less than 12 SVs are available, the remaining fields are output empty. If more than 12 SVs
are used, only the residuals of the first 12 SVs are output, in order to remain consistent
with the NMEA standard.
ID for CFG-MSG Number of fields
Message Info 0xF0 0x06 17
Message Structure:
$GPGRS,hhmmss.ss, mode {,residual}*cs<CR><LF>
Example:
$GPGRS,082632.00,1,0.54,0.83,1.00,1.02,-2.12,2.64,-0.71,-1.18,0.25,,,*70
Field
No.
Example Format Name Unit Description
0 $GPGRS string $GPGRS - Message ID, GRS protocol header
1 082632.00 hhmmss.sss hhmmss.
ss
- UTC Time, Time of associated position fix
2 1 digit mode - Mode (see table below), u-blox receivers will always
output Mode 1 residuals
Start of repeated block (12 times)
3 +
1*N
0.54 numeric residual m Range residuals for SVs used in navigation. The SV
order matches the order from the GSA sentence.
End of repeated block
15 *70 hexadecimal cs - Checksum
16 - character <CR><LF> - Carriage Return and Line Feed
Table Mode
Mode Description
0 Residuals were used to calculate the position given in the matching GGA sentence.
1 Residuals were recomputed after the GGA position was computed.
NMEA, UBX Protocol Specification, u-blox 5 GNSS Receiver
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NMEA Protocol
Page 45
GST
Message GST
Description GNSS Pseudo Range Error Statistics
Type Output Message
Comment -
ID for CFG-MSG Number of fields
Message Info 0xF0 0x07 11
Message Structure:
$GPGST,hhmmss.ss,range_rms,std_major,std_minor,hdg,std_lat,std_long,std_alt*cs<CR><LF>
Example:
$GPGST,082356.00,1.8,,,,1.7,1.3,2.2*7E
Field
No.
Example Format Name Unit Description
0 $GPGST string $GPGST - Message ID, GST protocol header
1 082356.00 hhmmss.sss hhmmss.
ss
- UTC Time, Time of associated position fix
2 1.8 numeric range_rm
s
m RMS value of the standard deviation of the ranges
3 - numeric std_majo
r
m Standard deviation of semi-major axis, not
supported (empty)
4 - numeric std_mino
r
m Standard deviation of semi-minor axis, not
supported (empty)
5 - numeric hdg degr
ees
Orientation of semi-major axis, not supported
(empty)
6 1.7 numeric std_lat m Standard deviation of latitude, error in meters
7 1.3 numeric std_long m Standard deviation of longitude, error in meters
8 2.2 numeric std_alt m Standard deviation of altitude, error in meters
9 *7E hexadecimal cs - Checksum
10 - character <CR><LF> - Carriage Return and Line Feed
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Page 46
ZDA
Message ZDA
Description Time and Date
Type Output Message
Comment -
ID for CFG-MSG Number of fields
Message Info 0xF0 0x08 9
Message Structure:
$GPZDA,hhmmss.ss,day,month,year,ltzh,ltzn*cs<CR><LF>
Example:
$GPZDA,082710.00,16,09,2002,00,00*64
Field
No.
Example Format Name Unit Description
0 $GPZDA string $GPZDA - Message ID, ZDA protocol header
1 082710.00 hhmmss.sss hhmmss.
ss
- UTC Time
2 16 dd day day UTC time: day, 01..31
3 09 mm month mon
th
UTC time: month, 01..12
4 2002 yyyy year year UTC time: 4 digit year
5 00 -xx ltzh - Local zone hours, not supported (fixed to 00)
6 00 zz ltzn - Local zone minutes, not supported (fixed to 00)
7 *64 hexadecimal cs - Checksum
8 - character <CR><LF> - Carriage Return and Line Feed
NMEA, UBX Protocol Specification, u-blox 5 GNSS Receiver
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NMEA Protocol
Page 47
GBS
Message GBS
Description GNSS Satellite Fault Detection
Type Output Message
Comment This message outputs the results of the Receiver Autonomous Integrity Monitoring
Algorithm (RAIM).
•The fields errlat, errlon and erralt output the standard deviation of the position
calculation, using all satellites which pass the RAIM test successfully.
•The fields errlat, errlon and erralt are only output if the RAIM process passed
successfully (i.e. no or successful Edits happened). These fields are never output if 4 or
fewer satellites are used for the navigation calculation (because - in this case - integrity
can not be determined by the receiver autonomously)
•The fields prob, bias and stdev are only output if at least one satellite failed in the
RAIM test. If more than one satellites fail the RAIM test, only the information for the
worst satellite is output in this message.
ID for CFG-MSG Number of fields
Message Info 0xF0 0x09 11
Message Structure:
$GPGBS,hhmmss.ss,errlat,errlon,erralt,svid,prob,bias,stddev*cs<CR><LF>
Example:
$GPGBS,235503.00,1.6,1.4,3.2,,,,*40
$GPGBS,235458.00,1.4,1.3,3.1,03,,-21.4,3.8*5B
Field
No.
Example Format Name Unit Description
0 $GPGBS string $GPGBS - Message ID, GBS protocol header
1 235503.00 hhmmss.sss hhmmss.
ss
- UTC Time, Time to which this RAIM sentence
belongs
2 1.6 numeric errlat m Expected error in latitude
3 1.4 numeric errlon m Expected error in longitude
4 3.2 numeric erralt m Expected error in altitude
5 03 numeric svid - Satellite ID of most likely failed satellite
6 - numeric prob - Probability of missed detection, no supported
(empty)
7 -21.4 numeric bias m Estimate on most likely failed satellite (a priori
residual)
8 3.8 numeric stddev m Standard deviation of estimated bias
9 *40 hexadecimal cs - Checksum
10 - character <CR><LF> - Carriage Return and Line Feed
NMEA, UBX Protocol Specification, u-blox 5 GNSS Receiver
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NMEA Protocol
Page 48
DTM
Message DTM
Description Datum Reference
Type Output Message
Comment This message gives the difference between the currently selected Datum, and the reference
Datum.
If the currently configured Datum is not WGS84 or WGS72, then the field LLL will be set to
999, and the field LSD is set to a variable-lenght string, representing the Name of the
Datum. The list of supported datums can be found in CFG-DAT.
The reference Datum can not be changed and is always set to WGS84.
ID for CFG-MSG Number of fields
Message Info 0xF0 0x0A 11
Message Structure:
$GPDTM,LLL,LSD,lat,N/S,lon,E/W,alt,RRR*cs<CR><LF>
Example:
$GPDTM,W84,,0.0,N,0.0,E,0.0,W84*6F
$GPDTM,W72,,0.00,S,0.01,W,-2.8,W84*4F
$GPDTM,999,CH95,0.08,N,0.07,E,-47.7,W84*1C
Field
No.
Example Format Name Unit Description
0 $GPDTM string $GPDTM - Message ID, DTM protocol header
1 W72 string LLL - Local Datum Code, W84 = WGS84, W72 = WGS72,
999 = user defined
2 - string LSD - Local Datum Subdivision Code, This field outputs
the currently selected Datum as a string (see also
note above).
3 0.08 numeric lat min
utes
Offset in Latitude
4 S character NS - North/South indicator
5 0.07 numeric lon min
utes
Offset in Longitude
6 E character EW - East/West indicator
7 -2.8 numeric alt m Offset in altitude
8 W84 string RRR - Reference Datum Code, W84 = WGS 84. This is the
only supported Reference datum.
9 *67 hexadecimal cs - Checksum
10 - character <CR><LF> - Carriage Return and Line Feed
NMEA, UBX Protocol Specification, u-blox 5 GNSS Receiver
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NMEA Protocol
Page 49
GPQ
Message GPQ
Description Poll message
Type Input Message
Comment Polls a standard NMEA message.
ID for CFG-MSG Number of fields
Message Info 0xF0 0x40 4
Message Structure:
$xxGPQ,sid*cs<CR><LF>
Example:
$EIGPQ,RMC*3A
Field
No.
Example Format Name Unit Description
0 $EIGPQ string $xxGPQ - Message ID, GPQ protocol header, xx = talker
identifier
1 RMC string sid - Sentence identifier
2 *3A hexadecimal cs - Checksum
3 - character <CR><LF> - Carriage Return and Line Feed
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Page 50
TXT
Message TXT
Description Text Transmission
Type Output Message
Comment This message is not configured through CFG-MSG, but instead through CFG-INF.
This message outputs various information on the receiver, such as power-up screen,
software version etc. This message can be configured using UBX Protocol message CFG-INF
ID for CFG-MSG Number of fields
Message Info 0xF0 0x41 7
Message Structure:
$GPTXT,xx,yy,zz,ascii data*cs<CR><LF>
Example:
$GPTXT,01,01,02,u-blox ag - www.u-blox.com*50
$GPTXT,01,01,02,ANTARIS ATR0620 HW 00000040*67
Field
No.
Example Format Name Unit Description
0 $GPTXT string $GPTXT - Message ID, TXT protocol header
1 01 numeric xx - Total number of messages in this transmission, 01..
99
2 01 numeric yy - Message number in this transmission, range 01..xx
3 02 numeric zz - Text identifier, u-blox GPS receivers specify the
severity of the message with this number.
- 00 = ERROR
- 01 = WARNING
- 02 = NOTICE
- 07 = USER
4 www.u-blox.
com
string string - Any ASCII text
5 *67 hexadecimal cs - Checksum
6 - character <CR><LF> - Carriage Return and Line Feed
NMEA, UBX Protocol Specification, u-blox 5 GNSS Receiver
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NMEA Protocol
Page 51
Proprietary Messages
Proprietary Messages : i.e. Messages defined by u-blox.
UBX,00
Message UBX,00
Description Lat/Long Position Data
Type Output Message
Comment The output of this message is dependent on the currently selected datum (Default:
WGS84)
This message contains position solution data. The datum selection may be changed using
the message CFG-DAT.
ID for CFG-MSG Number of fields
Message Info 0xF1 0x00 23
Message Structure:
$PUBX,00,hhmmss.ss,Latitude,N,Longitude,E,AltRef,NavStat,Hacc,Vacc,SOG,COG,Vvel,ageC,HDOP,VDOP,TDOP
,GU,RU,DR,*cs<CR><LF>
Example:
$PUBX,00,081350.00,4717.113210,N,00833.915187,E,546.589,G3,2.1,2.0,0.007,77.52,0.007,,0.92,1.19,0.7
7,9,0,0*5F
Field
No.
Example Format Name Unit Description
0 $PUBX string $PUBX - Message ID, UBX protocol header, proprietary
sentence
1 00 numeric ID - Propietary message identifier: 00
2 081350.00 hhmmss.sss hhmmss.
ss
- UTC Time, Current time
3 4717.113210 ddmm.mmmm Latitude - Latitude, Degrees + minutes, see Format description
4 N character N- N/S Indicator, N=north or S=south
5 00833.915187 dddmm.
mmmm
Longitud
e
- Longitude, Degrees + minutes, see Format
description
6 E character E- E/W indicator, E=east or W=west
7 546.589 numeric AltRef m Altitude above user datum ellipsoid.
8 G3 string NavStat - Navigation Status, See Table below
9 2.1 numeric Hacc m Horizontal accuracy estimate.
10 2.0 numeric Vacc m Vertical accuracy estimate.
11 0.007 numeric SOG km/
h
Speed over ground
12 77.52 numeric COG degr
ees
Course over ground
13 0.007 numeric Vvel m/s Vertical velocity, positive=downwards
14 - numeric ageC s Age of most recent DGPS corrections, empty = none
available
15 0.92 numeric HDOP - HDOP, Horizontal Dilution of Precision
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NMEA Protocol
Page 52
UBX,00 continued
Field
No.
Example Format Name Unit Description
16 1.19 numeric VDOP - VDOP, Vertical Dilution of Precision
17 0.77 numeric TDOP - TDOP, Time Dilution of Precision
18 9 numeric GU - Number of GPS satellites used in the navigation
solution
19 0 numeric RU - Number of GLONASS satellites used in the
navigation solution
20 0 numeric DR - DR used
21 *5B hexadecimal cs - Checksum
22 - character <CR><LF> - Carriage Return and Line Feed
Table Navigation Status
Navigation Status Description
NF No Fix
DR Predictive Dead Reckoning Solution
G2 Stand alone 2D solution
G3 Stand alone 3D solution
D2 Differential 2D solution
D3 Differential 3D solution
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Page 53
UBX,03
Message UBX,03
Description Satellite Status
Type Output Message
Comment The PUBX,03 message contains satellite status information.
ID for CFG-MSG Number of fields
Message Info 0xF1 0x03 5 + 6*GT
Message Structure:
$PUBX,03,GT{,SVID,s,AZM,EL,SN,LK},*cs<CR><LF>
Example:
$PUBX,03,11,23,-,,,45,010,29,-,,,46,013,07,-,,,42,015,08,U,067,31,42,025,10,U,195,33,46,026,18,U,32
6,08,39,026,17,-,,,32,015,26,U,306,66,48,025,27,U,073,10,36,026,28,U,089,61,46,024,15,-,,,39,014*0D
Field
No.
Example Format Name Unit Description
0 $PUBX string $PUBX - Message ID, UBX protocol header, proprietary
sentence
1 03 numeric ID - Propietary message identifier: 03
2 11 numeric GT - Number of GPS satellites tracked
Start of repeated block (GT times)
3 +
6*N
23 numeric SVID - Satellite PRN number
4 +
6*N
- character s- Satellite status, see table below
5 +
6*N
- numeric AZM degr
ees
Satellite azimuth, range 000..359
6 +
6*N
- numeric EL degr
ees
Satellite elevation, range 00..90
7 +
6*N
45 numeric SN dBH
z
Signal to noise ratio, range 00..55
8 +
6*N
010 numeric LK s Satellite carrier lock time, range 00..255
0 = code lock only
255 = lock for 255 seconds or more
End of repeated block
3 +
6*G
T
*0D hexadecimal cs - Checksum
4 +
6*G
T
- character <CR><LF> - Carriage Return and Line Feed
NMEA, UBX Protocol Specification, u-blox 5 GNSS Receiver
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NMEA Protocol
Page 54
Table Satellite Status
Satellite Status Description
- Not used
U Used in solution
e Available for navigation, but no ephemeris
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NMEA Protocol
Page 55
UBX,04
Message UBX,04
Description Time of Day and Clock Information
Type Output Message
Comment -
ID for CFG-MSG Number of fields
Message Info 0xF1 0x04 12
Message Structure:
$PUBX,04,hhmmss.ss,ddmmyy,UTC_TOW,week,reserved,Clk_B,Clk_D,PG,*cs<CR><LF>
Example:
$PUBX,04,073731.00,091202,113851.00,1196,113851.00,1930035,-2660.664,43,*3C
Field
No.
Example Format Name Unit Description
0 $PUBX string $PUBX - Message ID, UBX protocol header, proprietary
sentence
1 04 numeric ID - Propietary message identifier: 04
2 073731.00 hhmmss.sss hhmmss.
ss
- UTC Time, Current time in hour, minutes, seconds
3 091202 ddmmyy ddmmyy - UTC Date, day, month, year format
4 113851.00 numeric UTC_TOW s UTC Time of Week
5 1196 numeric week - GPS week numer, continues beyond 1023
6 113851.00 numeric reserved - reserved, for future use
7 1930035 numeric Clk_B ns Receiver clock bias
8 -2660.664 numeric Clk_D ns/s Receiver clock drift
9 43 numeric PG ns Timepulse Granularity, The quantization error of the
Timepulse pin
10 *3C hexadecimal cs - Checksum
11 - character <CR><LF> - Carriage Return and Line Feed
NMEA, UBX Protocol Specification, u-blox 5 GNSS Receiver
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NMEA Protocol
Page 56
UBX
Message UBX
Description Poll a PUBX message
Type Input Message
Comment A PUBX is message is polled by sending the PUBX message without any data fields.
ID for CFG-MSG Number of fields
Message Info 0xF1 0x40 4
Message Structure:
$PUBX,xx*cs<CR><LF>
Example:
$PUBX,04*37
Field
No.
Example Format Name Unit Description
0 $PUBX string $PUBX - Message ID, UBX protocol header, proprietary
sentence
1 04 numeric MsgID - Requested PUBX message identifier
2 *37 hexadecimal cs - Checksum
3 - character <CR><LF> - Carriage Return and Line Feed
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UBX,40
Message UBX,40
Description Set NMEA message output rate
Type Set Message
Comment Set/Get message rate configuration (s) to/from the receiver.
•Send rate is relative to the event a message is registered on. For example, if the rate of a
navigation message is set to 2, the message is sent every second navigation solution.
ID for CFG-MSG Number of fields
Message Info 0xF1 0x40 11
Message Structure:
$PUBX,40,msgId,rddc,rus1,rus2,rusb,rspi,reserved*cs<CR><LF>
Example:
$PUBX,40,GLL,1,0,0,0,0,0*5D
Field
No.
Example Format Name Unit Description
0 $PUBX string $PUBX - Message ID, UBX protocol header, proprietary
sentence
1 40 numeric ID - Proprietary message identifier
2 GLL string MsgId - NMEA message identifier
3 1 numeric rddc cycl
es
output rate on DDC
- 0 disables that message from being output on this
port
- 1 means that this message is output every epoch
4 1 numeric rus1 cycl
es
output rate on USART 1
- 0 disables that message from being output on this
port
- 1 means that this message is output every epoch
5 1 numeric rus2 cycl
es
output rate on USART 2
- 0 disables that message from being output on this
port
- 1 means that this message is output every epoch
6 1 numeric rusb cycl
es
output rate on USB
- 0 disables that message from being output on this
port
- 1 means that this message is output every epoch
7 1 numeric rspi cycl
es
output rate on SPI
- 0 disables that message from being output on this
port
- 1 means that this message is output every epoch
8 0 numeric reserved - Reserved, Always fill with 0
9 *5D hexadecimal cs - Checksum
10 - character <CR><LF> - Carriage Return and Line Feed
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UBX,41
Message UBX,41
Description Set Protocols and Baudrate
Type Set Message
Comment -
ID for CFG-MSG Number of fields
Message Info 0xF1 0x41 9
Message Structure:
$PUBX,41,portId,inProto,outProto,baudrate,autobauding*cs<CR><LF>
Example:
$PUBX,41,1,0007,0003,19200,0*25
Field
No.
Example Format Name Unit Description
0 $PUBX string $PUBX - Message ID, UBX protocol header, proprietary
sentence
1 41 numeric ID - Proprietary message identifier
2 1 numeric portID - ID of communication port, for a list of port IDs see
CFG-PRT.
3 0007 hexadecimal inProto - Input protocol mask. Bitmask, specifying which
protocols(s) are allowed for input. For details see
corresponding field in CFG-PRT.
4 0003 hexadecimal outProto - Output protocol mask. Bitmask, specifying which
protocols(s) are allowed for input. For details see
corresponding field in CFG-PRT.
5 19200 numeric baudrate bits/
s
Baudrate
6 0 numeric autobaud
ing
- Autobauding: 1=enable, 0=disable (not supported
on u-blox 5, set to 0)
7 *25 hexadecimal cs - Checksum
8 - character <CR><LF> - Carriage Return and Line Feed
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UBX Protocol
UBX Protocol Key Features
u-blox GPS receivers use a u-blox proprietary protocol to transmit GPS data to a host computer using
asynchronous RS232 ports. This protocol has the following key features:
• Compact - uses 8 Bit Binary Data.
• Checksum Protected - uses a low-overhead checksum algorithm
• Modular - uses a 2-stage message identifier (Class- and Message ID)
UBX Packet Structure
A basic UBX Packet looks as follows:
• Every Message starts with 2 Bytes: 0xB5 0x62
• A 1 Byte Class Field follows. The Class defines the basic subset of the message
• A 1 Byte ID Field defines the message that is to follow
•A 2 Byte Length Field is following. Length is defined as being the length of the payload, only. It does not
include Sync Chars, Length Field, Class, ID or CRC fields. The number format of the length field is an
unsigned 16-Bit integer in Little Endian Format.
• The Payload is a variable length field.
• CK_A and CK_B is a 16 Bit checksum whose calculation is defined below.
UBX Class IDs
A Class is a grouping of messages which are related to each other. The following table gives the short names,
description and Class ID Definitions.
Name Class Description
NAV 0x01 Navigation Results: Position, Speed, Time, Acc, Heading, DOP, SVs used
RXM 0x02 Receiver Manager Messages: Satellite Status, RTC Status
INF 0x04 Information Messages: Printf-Style Messages, with IDs such as Error, Warning, Notice
ACK 0x05 Ack/Nack Messages: as replies to CFG Input Messages
CFG 0x06 Configuration Input Messages: Set Dynamic Model, Set DOP Mask, Set Baud Rate, etc.
MON 0x0A Monitoring Messages: Comunication Status, CPU Load, Stack Usage, Task Status
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UBX Class IDs continued
Name Class Description
AID 0x0B AssistNow Aiding Messages: Ephemeris, Almanac, other A-GPS data input
TIM 0x0D Timing Messages: Timepulse Output, Timemark Results
All remaining class IDs are reserved.
UBX Payload Definition Rules
Structure Packing
Values are placed in an order that structure packing is not a problem. This means that 2Byte values shall start
on offsets which are a multiple of 2, 4-byte values shall start at a multiple of 4, and so on. This can easily be
achieved by placing the largest values first in the Message payload (e.g. R8), and ending with the smallest (i.e.
one-byters such as U1) values.
Message Naming
Referring to messages is done by adding the class name and a dash in front of the message name. For example,
the ECEF-Message is referred to as NAV-POSECEF. Referring to values is done by adding a dash and the name,
e.g. NAV-POSECEF-X
Number Formats
All multi-byte values are ordered in Little Endian format, unless otherwise indicated.
All floating point values are transmitted in IEEE754 single or double precision. A technical description of the
IEEE754 format can be found in the AnswerBook from the ADS1.x toolkit.
The following table gives information about the various values:
Short Type Size (Bytes) Comment Min/Max Resolution
U1 Unsigned Char 1 0..255 1
I1 Signed Char 1 2's complement -128..127 1
X1 Bitfield 1 n/a n/a
U2 Unsigned Short 2 0..65535 1
I2 Signed Short 2 2's complement -32768..32767 1
X2 Bitfield 2 n/a n/a
U4 Unsigned Long 4 0..4'294'967'295 1
I4 Signed Long 4 2's complement -2'147'483'648 ..
2'147'483'647
1
X4 Bitfield 4 n/a n/a
R4 IEEE 754 Single Precision 4 -1*2^+127 ..
2^+127
~ Value * 2^-24
R8 IEEE 754 Double Precision 8 -1*2^+1023 ..
2^+1023
~ Value * 2^-53
CH ASCII / ISO 8859.1 Encoding 1
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UBX Checksum
The checksum is calculated over the packet, starting and including the CLASS field, up until, but excluding, the
Checksum Field:
The checksum algorithm used is the 8-Bit Fletcher Algorithm, which is used in the TCP standard (RFC 1145).
This algorithm works as follows:
Buffer[N] contains the data over which the checksum is to be calculated.
The two CK_ values are 8-Bit unsigned integers, only! If implementing with larger-sized integer values, make
sure to mask both CK_A and CK_B with 0xFF after both operations in the loop.
CK_A = 0, CK_B = 0
For(I=0;I<N;I++)
{
CK_A = CK_A + Buffer[I]
CK_B = CK_B + CK_A
}
After the loop, the two U1 values contain the checksum, transmitted at the end of the packet.
UBX Message Flow
There are certain features associated with the messages being sent back and forth:
Acknowledgement
When messages from the Class CFG are sent to the receiver, the receiver will send an Acknowledge (ACK-ACK)
or a Not Acknowledge (ACK-NAK) message back to the sender, depending on whether or not the message
was processed correctly.
There is no ACK/NAK mechanism for message poll requests outside Class CFG.
Polling Mechanism
All messages that are output by the receiver in a periodic manner (i.e. Messages in Classes MON, NAV and
RXM) can also be polled.
There is not a single specific message which polls any other message. The UBX protocol was designed such,
that when sending a message with no payload (or just a single parameter which identifies the poll request) the
message is polled.
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UBX Messages Overview
Page Mnemonic Cls/ID Length Type Description
UBX Class ACK Ack/Nack Messages
82 ACK-ACK 0x05 0x01 2 Answer Message Acknowledged
82 ACK-NAK 0x05 0x00 2 Answer Message Not-Acknowledged
UBX Class AID AssistNow Aiding Messages
121 AID-ALM 0x0B 0x30 0 Poll Request Poll GPS Aiding Almanach Data
122 AID-ALM 0x0B 0x30 1 Poll Request Poll GPS Aiding Almanach Data for a SV
122 AID-ALM 0x0B 0x30 (8) or (40) Input/Output Message GPS Aiding Almanach Input/Output Message
124 AID-ALPSRV 0x0B 0x32 16 Output Message ALP client requests AlmanacPlus data from server
125 AID-ALPSRV 0x0B 0x32 16 + 1*dataSize Input Message ALP server sends AlmanacPlus data to client
125 AID-ALPSRV 0x0B 0x32 8 + 2*size Output Message ALP client sends AlmanacPlus data to server.
126 AID-ALP 0x0B 0x50 0 + 2*Variable Input message ALP file data transfer to the receiver
127 AID-ALP 0x0B 0x50 1 Input message Mark end of data transfer
127 AID-ALP 0x0B 0x50 1 Output message Acknowledges a data transfer
128 AID-ALP 0x0B 0x50 1 Output message Indicate problems with a data transfer
128 AID-ALP 0x0B 0x50 24 Periodic/Polled Poll the AlmanacPlus status
121 AID-DATA 0x0B 0x10 0 Poll Polls all GPS Initial Aiding Data
123 AID-EPH 0x0B 0x31 0 Poll Request Poll GPS Aiding Ephemeris Data
123 AID-EPH 0x0B 0x31 1 Poll Request Poll GPS Aiding Ephemeris Data for a SV
123 AID-EPH 0x0B 0x31 (8) or (104) Input/Output Message GPS Aiding Ephemeris Input/Output Message
119 AID-HUI 0x0B 0x02 0 Poll Request Poll GPS Health, UTC and ionosphere parameters
120 AID-HUI 0x0B 0x02 72 Input/Output Message GPS Health, UTC and ionosphere parameters
117 AID-INI 0x0B 0x01 0 Poll Request Poll GPS Initial Aiding Data
118 AID-INI 0x0B 0x01 48 Polled Aiding position, time, frequency, clock drift
117 AID-REQ 0x0B 0x00 0 Virtual Sends a poll (AID-DATA) for all GPS Aiding Data
UBX Class CFG Configuration Input Messages
101 CFG-ANT 0x06 0x13 0 Poll Request Poll Antenna Control Settings
101 CFG-ANT 0x06 0x13 4 Get/Set Get/Set Antenna Control Settings
99 CFG-CFG 0x06 0x09 (12) or (13) Command Clear, Save and Load configurations
95 CFG-DAT 0x06 0x06 0 Poll Request Poll Datum Setting
95 CFG-DAT 0x06 0x06 2 Set Set Standard Datum
95 CFG-DAT 0x06 0x06 44 Set Set User-defined Datum
96 CFG-DAT 0x06 0x06 52 Get Get currently selected Datum
92 CFG-INF 0x06 0x02 1 Poll Request Poll INF message configuration for one protocol
93 CFG-INF 0x06 0x02 0 + 8*Num Set/Get Information message configuration
91 CFG-MSG 0x06 0x01 2 Poll Request Poll a message configuration
91 CFG-MSG 0x06 0x01 8 Set/Get Set Message Rate(s)
92 CFG-MSG 0x06 0x01 3 Set/Get Set Message Rate
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UBX Messages Overview continued
Page Mnemonic Cls/ID Length Type Description
109 CFG-NAV5 0x06 0x24 0 Poll Request Poll Navigation Engine Settings
110 CFG-NAV5 0x06 0x24 36 Get/Set Get/Set Navigation Engine Settings
108 CFG-NAVX5 0x06 0x23 0 Poll Request Poll Navigation Engine Expert Settings
108 CFG-NAVX5 0x06 0x23 40 Get/Set Get/Set Navigation Engine Expert Settings
104 CFG-NMEA 0x06 0x17 0 Poll Request Poll the NMEA protocol configuration
104 CFG-NMEA 0x06 0x17 4 Set/Get Set/Get the NMEA protocol configuration
83 CFG-PRT 0x06 0x00 0 Poll Request Polls the configuration of the used I/O Port
83 CFG-PRT 0x06 0x00 1 Poll Request Polls the configuration for one I/O Port
84 CFG-PRT 0x06 0x00 20 Get/Set Get/Set Port Configuration for UART
85 CFG-PRT 0x06 0x00 20 Get/Set Get/Set Port Configuration for USB Port
86 CFG-PRT 0x06 0x00 20 Get/Set Get/Set Port Configuration for SPI Port
88 CFG-PRT 0x06 0x00 20 Get/Set Get/Set Port Configuration for DDC Port
89 CFG-PRT 0x06 0x00 20 Get/Set Get/Set Port Configuration for SPI Port
98 CFG-RATE 0x06 0x08 0 Poll Request Poll Navigation/Measurement Rate Settings
98 CFG-RATE 0x06 0x08 6 Get/Set Navigation/Measurement Rate Settings
94 CFG-RST 0x06 0x04 4 Command Reset Receiver / Clear Backup Data Structures
100 CFG-RXM 0x06 0x11 2 Set/Get RXM configuration
102 CFG-SBAS 0x06 0x16 8 Command SBAS Configuration
107 CFG-TMODE 0x06 0x1D 0 Poll Request Poll Time Mode Settings
107 CFG-TMODE 0x06 0x1D 28 Get/Set Time Mode Settings
97 CFG-TP 0x06 0x07 0 Poll Request Poll TimePulse Parameters
97 CFG-TP 0x06 0x07 20 Get/Set Get/Set TimePulse Parameters
105 CFG-USB 0x06 0x1B 0 Poll Request Poll a USB configuration
106 CFG-USB 0x06 0x1B 108 Get/Set Get/Set USB Configuration
UBX Class INF Information Messages
81 INF-DEBUG 0x04 0x04 0 + 1*variable ASCII String output, indicating debug output
79 INF-ERROR 0x04 0x00 0 + 1*variable ASCII String output, indicating an error
80 INF-NOTICE 0x04 0x02 0 + 1*variable ASCII String output, with informational contents
80 INF-TEST 0x04 0x03 0 + 1*variable ASCII String output, indicating test output
79 INF-WARNING 0x04 0x01 0 + 1*variable ASCII String output, indicating a warning
UBX Class MON Monitoring Messages
115 MON-HW 0x0A 0x09 68 Periodic/Polled Hardware Status
112 MON-IO 0x0A 0x02 0 + 20*NPRT Periodic/Polled I/O Subsystem Status
113 MON-MSGPP 0x0A 0x06 120 Periodic/Polled Message Parse and Process Status
114 MON-RXBUF 0x0A 0x07 24 Periodic/Polled Receiver Buffer Status
114 MON-TXBUF 0x0A 0x08 28 Periodic/Polled Transmitter Buffer Status
113 MON-VER 0x0A 0x04 40 + 30*Num Answer to Poll Receiver/Software Version
UBX Class NAV Navigation Results
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UBX Messages Overview continued
Page Mnemonic Cls/ID Length Type Description
73 NAV-CLOCK 0x01 0x22 20 Periodic/Polled Clock Solution
68 NAV-DOP 0x01 0x04 18 Periodic/Polled Dilution of precision
66 NAV-POSECEF 0x01 0x01 20 Periodic/Polled Position Solution in ECEF
66 NAV-POSLLH 0x01 0x02 28 Periodic/Polled Geodetic Position Solution
75 NAV-SBAS 0x01 0x32 12 + 12*cnt Periodic/Polled SBAS Status Data
69 NAV-SOL 0x01 0x06 52 Periodic/Polled Navigation Solution Information
67 NAV-STATUS 0x01 0x03 16 Periodic/Polled Receiver Navigation Status
73 NAV-SVINFO 0x01 0x30 8 + 12*numCh Periodic/Polled Space Vehicle Information
71 NAV-TIMEGPS 0x01 0x20 16 Periodic/Polled GPS Time Solution
72 NAV-TIMEUTC 0x01 0x21 20 Periodic/Polled UTC Time Solution
70 NAV-VELECEF 0x01 0x11 20 Periodic/Polled Velocity Solution in ECEF
71 NAV-VELNED 0x01 0x12 36 Periodic/Polled Velocity Solution in NED
UBX Class RXM Receiver Manager Messages
77 RXM-SVSI 0x02 0x20 8 + 6*numSV Periodic/Polled SV Status Info
UBX Class TIM Timing Messages
131 TIM-SVIN 0x0D 0x04 28 Periodic/Polled Survey-in data
130 TIM-TM2 0x0D 0x03 28 Periodic/Polled Time mark data
129 TIM-TP 0x0D 0x01 16 Periodic/Polled Timepulse Timedata
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NAV (0x01)
Navigation Results: i.e. Position, Speed, Time, Acc, Heading, DOP, SVs used.
Messages in the NAV Class output Navigation Data such as position, altitude and velocity in a number of
formats. Additionally, status flags and accuracy figures are output.
NAV-POSECEF (0x01 0x01)
Position Solution in ECEF
Message NAV-POSECEF
Description Position Solution in ECEF
Type Periodic/Polled
Comment -
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x01 0x01 20 see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 U4 - iTOW ms GPS Millisecond Time of Week
4 I4 - ecefX cm ECEF X coordinate
8 I4 - ecefY cm ECEF Y coordinate
12 I4 - ecefZ cm ECEF Z coordinate
16 U4 - pAcc cm Position Accuracy Estimate
NAV-POSLLH (0x01 0x02)
Geodetic Position Solution
Message NAV-POSLLH
Description Geodetic Position Solution
Type Periodic/Polled
Comment This message outputs the Geodetic position in the currently selected Ellipsoid. The default
is the WGS84 Ellipsoid, but can be changed with the message CFG-DAT.
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x01 0x02 28 see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 U4 - iTOW ms GPS Millisecond Time of Week
4 I4 1e-7 lon deg Longitude
8 I4 1e-7 lat deg Latitude
12 I4 - height mm Height above Ellipsoid
16 I4 - hMSL mm Height above mean sea level
20 U4 - hAcc mm Horizontal Accuracy Estimate
24 U4 - vAcc mm Vertical Accuracy Estimate
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NAV-STATUS (0x01 0x03)
Receiver Navigation Status
Message NAV-STATUS
Description Receiver Navigation Status
Type Periodic/Polled
Comment -
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x01 0x03 16 see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 U4 - iTOW ms GPS Millisecond Time of Week
4 U1 - gpsFix - GPSfix Type
- 0x00 = no fix
- 0x01 = dead reckoning only
- 0x02 = 2D-fix
- 0x03 = 3D-fix
- 0x04 = GPS + dead reckoning combined
- 0x05 = Time only fix
- 0x06..0xff = reserved
5 X1 - flags - Navigation Status Flags (see graphic below)
6 X1 - diffStat - Differential Status (see graphic below)
7 U1 - res - Reserved
8 U4 - ttff - Time to first fix (millisecond time tag)
12 U4 - msss - Milliseconds since Startup / Reset
Bitfield flags
This Graphic explains the bits of flags
Name Description
gpsFixOk within DOP and ACC Masks
diffSoln 1 if DGPS used
wknSet 1 if Week Number valid
towSet 1 if Time of Week valid
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Bitfield diffStat
This Graphic explains the bits of diffStat
Name Description
dgpsIStat DGPS Input Status
00: none
01: PR+PRR Correction
10: PR+PRR+CP Correction
11: High accuracy PR+PRR+CP Correction
NAV-DOP (0x01 0x04)
Dilution of precision
Message NAV-DOP
Description Dilution of precision
Type Periodic/Polled
Comment • DOP values are dimensionless.
•All DOP values are scaled by a factor of 100. If the unit transmits a value of e.g. 156, the
DOP value is 1.56.
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x01 0x04 18 see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 U4 - iTOW ms GPS Millisecond Time of Week
4 U2 0.01 gDOP - Geometric DOP
6 U2 0.01 pDOP - Position DOP
8 U2 0.01 tDOP - Time DOP
10 U2 0.01 vDOP - Vertical DOP
12 U2 0.01 hDOP - Horizontal DOP
14 U2 0.01 nDOP - Northing DOP
16 U2 0.01 eDOP - Easting DOP
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NAV-SOL (0x01 0x06)
Navigation Solution Information
Message NAV-SOL
Description Navigation Solution Information
Type Periodic/Polled
Comment This message combines Position, velocity and time solution in ECEF, including accuracy
figures
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x01 0x06 52 see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 U4 - iTOW ms GPS Millisecond Time of Week
4 I4 - fTOW ns Fractional Nanoseconds remainder of rounded
ms above, range -500000 .. 500000
8 I2 - week - GPS week (GPS time)
10 U1 - gpsFix - GPSfix Type, range 0..4
0x00 = No Fix
0x01 = Dead Reckoning only
0x02 = 2D-Fix
0x03 = 3D-Fix
0x04 = GPS + dead reckoning combined
0x05 = Time only fix
0x06..0xff: reserved
11 X1 - flags - Fix Status Flags (see graphic below)
12 I4 - ecefX cm ECEF X coordinate
16 I4 - ecefY cm ECEF Y coordinate
20 I4 - ecefZ cm ECEF Z coordinate
24 U4 - pAcc cm 3D Position Accuracy Estimate
28 I4 - ecefVX cm/s ECEF X velocity
32 I4 - ecefVY cm/s ECEF Y velocity
36 I4 - ecefVZ cm/s ECEF Z velocity
40 U4 - sAcc cm/s Speed Accuracy Estimate
44 U2 0.01 pDOP - Position DOP
46 U1 - res1 - reserved
47 U1 - numSV - Number of SVs used in Nav Solution
48 U4 - res2 - reserved
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Bitfield flags
This Graphic explains the bits of flags
Name Description
GPSfixOK i.e within DOP & ACC Masks
DiffSoln 1 if DGPS used
WKNSET 1 if Week Number valid
TOWSET 1 if Time of Week valid
NAV-VELECEF (0x01 0x11)
Velocity Solution in ECEF
Message NAV-VELECEF
Description Velocity Solution in ECEF
Type Periodic/Polled
Comment -
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x01 0x11 20 see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 U4 - iTOW ms GPS Millisecond Time of Week
4 I4 - ecefVX cm/s ECEF X velocity
8 I4 - ecefVY cm/s ECEF Y velocity
12 I4 - ecefVZ cm/s ECEF Z velocity
16 U4 - sAcc cm/s Speed Accuracy Estimate
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NAV-VELNED (0x01 0x12)
Velocity Solution in NED
Message NAV-VELNED
Description Velocity Solution in NED
Type Periodic/Polled
Comment -
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x01 0x12 36 see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 U4 - iTOW ms GPS Millisecond Time of Week
4 I4 - velN cm/s NED north velocity
8 I4 - velE cm/s NED east velocity
12 I4 - velD cm/s NED down velocity
16 U4 - speed cm/s Speed (3-D)
20 U4 - gSpeed cm/s Ground Speed (2-D)
24 I4 1e-5 heading deg Heading 2-D
28 U4 - sAcc cm/s Speed Accuracy Estimate
32 U4 1e-5 cAcc deg Course / Heading Accuracy Estimate
NAV-TIMEGPS (0x01 0x20)
GPS Time Solution
Message NAV-TIMEGPS
Description GPS Time Solution
Type Periodic/Polled
Comment -
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x01 0x20 16 see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 U4 - iTOW ms GPS Millisecond time of Week
4 I4 - fTOW ns Fractional Nanoseconds remainder of rounded
ms above, range -500000 .. 500000
8 I2 - week - GPS week (GPS time)
10 I1 - leapS s Leap Seconds (GPS-UTC)
11 X1 - valid - Validity Flags (see graphic below)
12 U4 - tAcc ns Time Accuracy Estimate
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Bitfield valid
This Graphic explains the bits of valid
Name Description
tow 1=Valid Time of Week
week 1=Valid Week Number
utc 1=Valid Leap Seconds, i.e. Leap Seconds already known
NAV-TIMEUTC (0x01 0x21)
UTC Time Solution
Message NAV-TIMEUTC
Description UTC Time Solution
Type Periodic/Polled
Comment -
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x01 0x21 20 see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 U4 - iTOW ms GPS Millisecond Time of Week
4 U4 - tAcc ns Time Accuracy Estimate
8 I4 - nano ns Nanoseconds of second, range -500000000 ..
500000000 (UTC)
12 U2 - year y Year, range 1999..2099 (UTC)
14 U1 - month month Month, range 1..12 (UTC)
15 U1 - day d Day of Month, range 1..31 (UTC)
16 U1 - hour h Hour of Day, range 0..23 (UTC)
17 U1 - min min Minute of Hour, range 0..59 (UTC)
18 U1 - sec s Seconds of Minute, range 0..59 (UTC)
19 X1 - valid - Validity Flags (see graphic below)
Bitfield valid
This Graphic explains the bits of valid
Name Description
validTOW 1 = Valid Time of Week
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Bitfield valid Description continued
Name Description
validWKN 1 = Valid Week Number
validUTC 1 = Valid UTC (Leap Seconds already known)
NAV-CLOCK (0x01 0x22)
Clock Solution
Message NAV-CLOCK
Description Clock Solution
Type Periodic/Polled
Comment -
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x01 0x22 20 see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 U4 - iTOW ms GPS Millisecond Time of week
4 I4 - clkB ns Clock bias in nanoseconds
8 I4 - clkD ns/s Clock drift in nanoseconds per second
12 U4 - tAcc ns Time Accuracy Estimate
16 U4 - fAcc ps/s Frequency Accuracy Estimate
NAV-SVINFO (0x01 0x30)
Space Vehicle Information
Message NAV-SVINFO
Description Space Vehicle Information
Type Periodic/Polled
Comment -
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x01 0x30 8 + 12*numCh see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 U4 - iTOW ms GPS Millisecond time of week
4 U1 - numCh - Number of channels
5 X1 - globalFlags - Bitmask (see graphic below)
6 U2 - res2 - Reserved
Start of repeated block (numCh times)
8 + 12*N U1 - chn - Channel number
9 + 12*N U1 - svid - Satellite ID
10 + 12*N X1 - flags - Bitmask (see graphic below)
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NAV-SVINFO continued
Byte Offset Number
Format
Scaling Name Unit Description
11 + 12*N X1 - quality - Bitfield (see graphic below)
12 + 12*N U1 - cno dbHz Carrier to Noise Ratio (Signal Strength)
13 + 12*N I1 - elev deg Elevation in integer degrees
14 + 12*N I2 - azim deg Azimuth in integer degrees
16 + 12*N I4 - prRes cm Pseudo range residual in centimetres
End of repeated block
Bitfield globalFlags
This Graphic explains the bits of globalFlags
Name Description
isU5 u-blox 5 generation receiver
Bitfield flags
This Graphic explains the bits of flags
Name Description
svUsed SV is used for navigation
diffCorr Differential correction data is available for this SV
orbitAvail Orbit information is available for this SV (Ephemeris or Almanach)
orbitEph Orbit information is Ephemeris
unhealthy SV is unhealthy / shall not be used
orbitAlm Orbit information is Almanac Plus
Bitfield quality
This Graphic explains the bits of quality
Name Description
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Bitfield quality Description continued
Name Description
qualityInd Signal Quality indicator (range 0..7). The following list shows the meaning of the different QI values:
0: This channel is idle
1: Channel is searching
2: Signal aquired
3: Signal detected but unusable
4: Code Lock on Signal
5, 6: Code and Carrier locked
7: Code and Carrier locked, receiving 50bps data
NAV-SBAS (0x01 0x32)
SBAS Status Data
Message NAV-SBAS
Description SBAS Status Data
Type Periodic/Polled
Comment This message outputs the status of the SBAS sub system
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x01 0x32 12 + 12*cnt see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 U4 - iTOW ms GPS Millisecond time of week
4 U1 - geo - PRN Number of the GEO where correction and
integrity data is used from
5 U1 - mode - SBAS Mode
0 Disabled
1 Enabled Integrity
3 Enabled Testmode
6 I1 - sys - SBAS System (WAAS/EGNOS/...)
-1 Unknown
0 WAAS
1 EGNOS
2 MSAS
16 GPS
7 X1 - service - SBAS Services available (see graphic below)
8 U1 - cnt - Number of SV data following
9 U1[3] - res - Reserved
Start of repeated block (cnt times)
12 + 12*N U1 - svid - SV Id
13 + 12*N U1 - flags - Flags for this SV
14 + 12*N U1 - udre - Monitoring status
15 + 12*N U1 - svSys - System (WAAS/EGNOS/...)
same as SYS
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NAV-SBAS continued
Byte Offset Number
Format
Scaling Name Unit Description
16 + 12*N U1 - svService - Services available
same as SERVICE
17 + 12*N U1 - res0 - Reserved
18 + 12*N I2 - prc cm Pseudo Range correction in [cm]
20 + 12*N I2 - res1 - Reserved
22 + 12*N I2 - ic cm Ionosphere correction in [cm]
End of repeated block
Bitfield service
This Graphic explains the bits of service
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RXM (0x02)
Receiver Manager Messages: i.e. Satellite Status, RTC Status.
Messages in Class RXM output status and result data from the Receiver Manager.
RXM-SVSI (0x02 0x20)
SV Status Info
Message RXM-SVSI
Description SV Status Info
Type Periodic/Polled
Comment Status of the receiver manager knowledge about GPS Orbit Validity
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x02 0x20 8 + 6*numSV see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 I4 - iTOW ms Measurement integer millisecond GPS time of
week
4 I2 - week weeks Measurement GPS week number.
6 U1 - numVis - Number of visible satellites
7 U1 - numSV - Number of per-SV data blocks following
Start of repeated block (numSV times)
8 + 6*N U1 - svid - Satellite ID
9 + 6*N X1 - svFlag - Information Flags (see graphic below)
10 + 6*N I2 - azim - Azimuth
12 + 6*N I1 - elev - Elevation
13 + 6*N X1 - age - Age of Almanach and Ephemeris: (see graphic
below)
End of repeated block
Bitfield svFlag
This Graphic explains the bits of svFlag
Name Description
ura Figure of Merit (URA) range 0..15
healthy SV healthy flag
ephVal Ephemeris valid
almVal Almanach valid
notAvail SV not available
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Bitfield age
This Graphic explains the bits of age
Name Description
almAge Age of ALM in days offset by 4
i.e. the reference time may be in the future:
ageOfAlm = (age & 0x0f) - 4
ephAge Age of EPH in hours offset by 4.
i.e. the reference time may be in the future:
ageOfEph = ((age & 0xf0) >> 4) - 4
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INF (0x04)
Information Messages: i.e. Printf-Style Messages, with IDs such as Error, Warning, Notice.
The INF Class is basically an output class that allows the firmware and application code to output strings with a
printf-style call. All INF messages have an associated type to indicate the kind of message.
INF-ERROR (0x04 0x00)
ASCII String output, indicating an error
Message INF-ERROR
Description ASCII String output, indicating an error
Type
Comment This message has a variable length payload, representing an ASCII string.
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x04 0x00 0 + 1*variable see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
Start of repeated block (variable times)
N*1 CH - char - ASCII Character
End of repeated block
INF-WARNING (0x04 0x01)
ASCII String output, indicating a warning
Message INF-WARNING
Description ASCII String output, indicating a warning
Type
Comment This message has a variable length payload, representing an ASCII string.
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x04 0x01 0 + 1*variable see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
Start of repeated block (variable times)
N*1 CH - char - ASCII Character
End of repeated block
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INF-NOTICE (0x04 0x02)
ASCII String output, with informational contents
Message INF-NOTICE
Description ASCII String output, with informational contents
Type
Comment This message has a variable length payload, representing an ASCII string.
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x04 0x02 0 + 1*variable see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
Start of repeated block (variable times)
N*1 CH - char - ASCII Character
End of repeated block
INF-TEST (0x04 0x03)
ASCII String output, indicating test output
Message INF-TEST
Description ASCII String output, indicating test output
Type
Comment This message has a variable length payload, representing an ASCII string.
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x04 0x03 0 + 1*variable see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
Start of repeated block (variable times)
N*1 CH - char - ASCII Character
End of repeated block
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INF-DEBUG (0x04 0x04)
ASCII String output, indicating debug output
Message INF-DEBUG
Description ASCII String output, indicating debug output
Type
Comment This message has a variable length payload, representing an ASCII string.
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x04 0x04 0 + 1*variable see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
Start of repeated block (variable times)
N*1 CH - char - ASCII Character
End of repeated block
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ACK (0x05)
Ack/Nack Messages: i.e. as replies to CFG Input Messages.
Messages in this class are sent as a result of a CFG message being received, decoded and processed by the
receiver.
ACK-NAK (0x05 0x00)
Message Not-Acknowledged
Message ACK-NAK
Description Message Not-Acknowledged
Type Answer
Comment Output upon processing of an input message
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x05 0x00 2 see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 U1 - clsID - Class ID of the Not-Acknowledged Message
1 U1 - msgID - Message ID of the Not-Acknowledged Message
ACK-ACK (0x05 0x01)
Message Acknowledged
Message ACK-ACK
Description Message Acknowledged
Type Answer
Comment Output upon processing of an input message
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x05 0x01 2 see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 U1 - clsID - Class ID of the Acknowledged Message
1 U1 - msgID - Message ID of the Acknowledged Message
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CFG (0x06)
Configuration Input Messages: i.e. Set Dynamic Model, Set DOP Mask, Set Baud Rate, etc..
The CFG Class can be used to configure the receiver and read out current configuration values. Any messages
in Class CFG sent to the receiver are acknowledged (with Message ACK-ACK) if processed successfully, and
rejected (with Message ACK-NAK) if processing the message failed.
CFG-PRT (0x06 0x00)
Polls the configuration of the used I/O Port
Message CFG-PRT
Description Polls the configuration of the used I/O Port
Type Poll Request
Comment Polls the configuration of the I/O Port on which this message is received
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x06 0x00 0 see below CK_A CK_B
No payload
Polls the configuration for one I/O Port
Message CFG-PRT
Description Polls the configuration for one I/O Port
Type Poll Request
Comment Sending this message with a port ID as payload results in having the receiver return the
configuration for the specified port.
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x06 0x00 1 see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 U1 - PortID - Port Identifier Number (see the other versions of
CFG-PRT for valid values)
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Get/Set Port Configuration for UART
Message CFG-PRT
Description Get/Set Port Configuration for UART
Type Get/Set
Comment Several configurations can be concatenated to one input message. In this case the payload
length can be a multiple of the normal length (see the other versions of CFG-PRT). Output
messages from the module contain only one configuration unit.
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x06 0x00 20 see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 U1 - portID - Port Identifier Number (= 1 or 2 for UART ports)
1 U1 - res0 - Reserved 
2 U2 - res1 - Reserved
4 X4 - mode - A bit mask describing the UART mode (see
graphic below)
8 U4 - baudRate Bits/s Baudrate in bits/second
12 X2 - inProtoMask - A mask describing which input protocols are
active.
Each bit of this mask is used for a protocol.
Through that, multiple protocols can be defined
on a single port. (see graphic below)
14 X2 - outProtoMask - A mask describing which output protocols are
active.
Each bit of this mask is used for a protocol.
Through that, multiple protocols can be defined
on a single port. (see graphic below)
16 X2 - flags - Reserved, set to 0
18 U2 - pad - Reserved, set to 0
Bitfield mode
This Graphic explains the bits of mode
Name Description
charLen Character Length
00 5bit (not supported)
01 6bit (not supported)
10 7bit (supported only with parity)
11 8bit
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Bitfield mode Description continued
Name Description
parity 000 Even Parity
001 Odd Parity
10X No Parity
X1X Reserved
nStopBits Number of Stop Bits
00 1 Stop Bit
01 1.5 Stop Bit
10 2 Stop Bit
11 0.5 Stop Bit
Bitfield inProtoMask
This Graphic explains the bits of inProtoMask
Bitfield outProtoMask
This Graphic explains the bits of outProtoMask
Get/Set Port Configuration for USB Port
Message CFG-PRT
Description Get/Set Port Configuration for USB Port
Type Get/Set
Comment Several configurations can be concatenated to one input message. In this case the payload
length can be a multiple of the normal length (see the other versions of CFG-PRT). Output
messages from the module contain only one configuration unit.
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x06 0x00 20 see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 U1 - portID - Port Identifier Number (= 3 for USB port)
1 U1 - res0 - Reserved 
2 U2 - res1 - Reserved
4 U4 - res2 - Reserved
8 U4 - res3 - Reserved
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CFG-PRT continued
Byte Offset Number
Format
Scaling Name Unit Description
12 X2 - inProtoMask - A mask describing which input protocols are
active.
Each bit of this mask is used for a protocol.
Through that, multiple protocols can be defined
on a single port. (see graphic below)
14 X2 - outProtoMask - A mask describing which output protocols are
active.
Each bit of this mask is used for a protocol.
Through that, multiple protocols can be defined
on a single port. (see graphic below)
16 X2 - flags - Reserved, set to 0
18 U2 - pad - Reserved, set to 0
Bitfield inProtoMask
This Graphic explains the bits of inProtoMask
Bitfield outProtoMask
This Graphic explains the bits of outProtoMask
Get/Set Port Configuration for SPI Port
Message CFG-PRT
Description Get/Set Port Configuration for SPI Port
Type Get/Set
Comment Several configurations can be concatenated to one input message. In this case the payload
length can be a multiple of the normal length (see the other versions of CFG-PRT). Output
messages from the module contain only one configuration unit.
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x06 0x00 20 see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 U1 - portID - Port Identifier Number (= 4 for SPI port)
1 U1 - res0 - Reserved 
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CFG-PRT continued
Byte Offset Number
Format
Scaling Name Unit Description
2 U2 - res1 - Reserved
4 X4 - mode - SPI Mode Flags (see graphic below)
8 U4 - res2 - Reserved
12 X2 - inProtoMask - A mask describing which input protocols are
active.
Each bit of this mask is used for a protocol.
Through that, multiple protocols can be defined
on a single port. (see graphic below)
14 X2 - outProtoMask - A mask describing which output protocols are
active.
Each bit of this mask is used for a protocol.
Through that, multiple protocols can be defined
on a single port. (see graphic below)
16 X2 - flags - Reserved, set to 0
18 U2 - pad - Reserved, set to 0
Bitfield mode
This Graphic explains the bits of mode
Name Description
spiMode 00 SPI Mode 0: CPOL = 0, CPHA = 0
01 SPI Mode 1: CPOL = 0, CPHA = 1
10 SPI Mode 2: CPOL = 1, CPHA = 0
11 SPI Mode 3: CPOL = 1, CPHA = 1
ffCnt Number of bytes containing 0xFF to receive before switching off reception. Range: 0(mechanism off)-255
Bitfield inProtoMask
This Graphic explains the bits of inProtoMask
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Bitfield outProtoMask
This Graphic explains the bits of outProtoMask
Get/Set Port Configuration for DDC Port
Message CFG-PRT
Description Get/Set Port Configuration for DDC Port
Type Get/Set
Comment Several configurations can be concatenated to one input message. In this case the payload
length can be a multiple of the normal length (see the other versions of CFG-PRT). Output
messages from the module contain only one configuration unit.
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x06 0x00 20 see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 U1 - portID - Port Identifier Number (= 0 for DDC port)
1 U1 - res0 - Reserved 
2 U2 - res1 - Reserved
4 X4 - mode - DDC Mode Flags (see graphic below)
8 U4 - res2 - Reserved
12 X2 - inProtoMask - A mask describing which input protocols are
active.
Each bit of this mask is used for a protocol.
Through that, multiple protocols can be defined
on a single port. (see graphic below)
14 X2 - outProtoMask - A mask describing which output protocols are
active.
Each bit of this mask is used for a protocol.
Through that, multiple protocols can be defined
on a single port. (see graphic below)
16 X2 - flags - Reserved, set to 0
18 U2 - pad - Reserved, set to 0
Bitfield mode
This Graphic explains the bits of mode
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Bitfield mode Description continued
Name Description
Name Description
slaveAddr Slave address
Range: 0x07 < slaveAddr < 0x78. Bit 0 must be 0
Bitfield inProtoMask
This Graphic explains the bits of inProtoMask
Bitfield outProtoMask
This Graphic explains the bits of outProtoMask
Get/Set Port Configuration for SPI Port
Message CFG-PRT
Description Get/Set Port Configuration for SPI Port
Type Get/Set
Comment Several configurations can be concatenated to one input message. In this case the payload
length can be a multiple of the normal length (see the other versions of CFG-PRT). Output
messages from the module contain only one configuration unit.
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x06 0x00 20 see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 U1 - portID - Port Identifier Number (= 4 for SPI port)
1 U1 - res0 - Reserved 
2 U2 - res1 - Reserved
4 X4 - mode - SPI Mode Flags (see graphic below)
8 U4 - res2 - Reserved
12 X2 - inProtoMask - A mask describing which input protocols are
active
Each bit of this mask is used for a protocol.
Through that, multiple protocols can be defined
on a single port (see graphic below)
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CFG-PRT continued
Byte Offset Number
Format
Scaling Name Unit Description
14 X2 - outProtoMask - A mask describing which output protocols are
active.
Each bit of this mask is used for a protocol.
Through that, multiple protocols can be defined
on a single port (see graphic below)
16 X2 - flags - Reserved, set to 0
18 U2 - pad - Reserved, set to 0
Bitfield mode
This Graphic explains the bits of mode
Name Description
spiMode 00 SPI Mode 0: CPOL = 0, CPHA = 0
01 SPI Mode 1: CPOL = 0, CPHA = 1
10 SPI Mode 2: CPOL = 1, CPHA = 0
11 SPI Mode 3: CPOL = 1, CPHA = 1
flowControl 0 Flow control disabled
1 Flow control enabled (9-bit mode)
ffCnt Number of bytes containing 0xFF to receive before switching off reception. Range: 0(mechanism off)-255
Bitfield inProtoMask
This Graphic explains the bits of inProtoMask
Bitfield outProtoMask
This Graphic explains the bits of outProtoMask
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CFG-MSG (0x06 0x01)
Poll a message configuration
Message CFG-MSG
Description Poll a message configuration
Type Poll Request
Comment -
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x06 0x01 2 see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 U1 - class - Message Class
1 U1 - msgID - Message Identifier
Set Message Rate(s)
Message CFG-MSG
Description Set Message Rate(s)
Type Set/Get
Comment Set/Get message rate configuration (s) to/from the receiver. See also section How to change
between protocols.
•Send rate is relative to the event a message is registered on. For example, if the rate of a
navigation message is set to 2, the message is sent every second navigation solution.For
configuring NMEA messages, the section NMEA Messages Overview describes Class and
Identifier numbers used.
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x06 0x01 8 see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 U1 - class - Message Class
1 U1 - msgID - Message Identifier
2 U1[6] - rate - Send rate on I/O Target (6 Targets)
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Set Message Rate
Message CFG-MSG
Description Set Message Rate
Type Set/Get
Comment Set message rate configuration for the current target. See also section How to change
between protocols.
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x06 0x01 3 see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 U1 - class - Message Class
1 U1 - msgID - Message Identifier
2 U1 - rate - Send rate on current Target
CFG-INF (0x06 0x02)
Poll INF message configuration for one protocol
Message CFG-INF
Description Poll INF message configuration for one protocol
Type Poll Request
Comment -
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x06 0x02 1 see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 U1 - protocolID - Protocol Identifier, identifying the output
protocol for this Poll Request. The following are
valid Protocol Identifiers:
- 0: UBX Protocol
- 1: NMEA Protocol
- 2-255: Reserved
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Information message configuration
Message CFG-INF
Description Information message configuration
Type Set/Get
Comment The value of INFMSG_mask<x> below are that each bit represents one of the INF class
messages (Bit 0 for ERROR, Bit 1 for WARNING and so on.). For a complete list, please see
the Message Class INF. Several configurations can be concatenated to one input message.
In this case the payload length can be a multiple of the normal length. Output messages
from the module contain only one configuration unit. Please note that I/O Targets 0, 1 and
2 correspond to serial ports 0, 1 and 2. I/O target 3 is reserved for future use.
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x06 0x02 0 + 8*Num see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
Start of repeated block (Num times)
N*8 U1 - protocolID - Protocol Identifier, identifying for which
protocol the configuration is set/get. The
following are valid Protocol Identifiers:
- 0: UBX Protocol
- 1: NMEA Protocol
- 2-255: Reserved
1 + 8*N U1 - res0 - Reserved
2 + 8*N U2 - res1 - Reserved
4 + 8*N X1[4] - infMsgMask - A bit mask, saying which information messages
are enabled on each I/O target (see graphic
below)
End of repeated block
Bitfield infMsgMask
This Graphic explains the bits of infMsgMask
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CFG-RST (0x06 0x04)
Reset Receiver / Clear Backup Data Structures
Message CFG-RST
Description Reset Receiver / Clear Backup Data Structures
Type Command
Comment -
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x06 0x04 4 see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 X2 - navBbrMask - BBR Sections to clear. The following Special Sets
apply:
0x0000 Hotstart
0x0001 Warmstart
0xFFFF Coldstart (see graphic below)
2 U1 - resetMode - Reset Type
- 0x00 - Hardware Reset (Watchdog)
- 0x01 - Controlled Software reset
- 0x02 - Controlled Software reset (GPS only)
- 0x08 - Controlled GPS stop
- 0x09 - Controlled GPS start
3 U1 - res - Reserved
Bitfield navBbrMask
This Graphic explains the bits of navBbrMask
Name Description
eph Ephemeris
alm Almanach
health Health
klob Klobuchard
pos Position
clkd Clock Drift
osc Oscilator Parameter
utc UTC Correction Parameters
rtc RTC
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CFG-DAT (0x06 0x06)
Poll Datum Setting
Message CFG-DAT
Description Poll Datum Setting
Type Poll Request
Comment Upon sending of this message, the receiver returns CFG-DAT as defined below
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x06 0x06 0 see below CK_A CK_B
No payload
Set Standard Datum
Message CFG-DAT
Description Set Standard Datum
Type Set
Comment See section Geodetic Datums for a list of supported Datums
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x06 0x06 2 see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 U2 - datumNum - Datum Number
Set User-defined Datum
Message CFG-DAT
Description Set User-defined Datum
Type Set
Comment -
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x06 0x06 44 see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 R8 - majA m Semi-major Axis ( accepted range = 6,300,000.0
to 6,500,000.0 metres ).
8 R8 - flat - 1.0 / Flattening ( accepted range is 0.0 to 500.0
).
16 R4 - dX m X Axis shift at the origin ( accepted range is +/-
5000.0 metres ).
20 R4 - dY m Y Axis shift at the origin ( accepted range is +/-
5000.0 metres ).
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CFG-DAT continued
Byte Offset Number
Format
Scaling Name Unit Description
24 R4 - dZ m Z Axis shift at the origin ( accepted range is +/-
5000.0 metres ).
28 R4 - rotX s Rotation about the X Axis ( accepted range is
+/- 20.0 milli-arc seconds ).
32 R4 - rotY s Rotation about the Y Axis ( accepted range is
+/- 20.0 milli-arc seconds ).
36 R4 - rotZ s Rotation about the Z Axis ( accepted range is +/-
20.0 milli-arc seconds ).
40 R4 - scale ppm Scale change ( accepted range is 0.0 to 50.0
parts per million ).
Get currently selected Datum
Message CFG-DAT
Description Get currently selected Datum
Type Get
Comment The Parameter datumName is only valid, if datumNum is not equal to -1. In case
datumNum is -1,the receiver is configured for a custom datum. The parameters from majA
to scale are valid for both custom or standard datum formats.
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x06 0x06 52 see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 U2 - datumNum - Datum Number according to Geodetic Datums
2 CH[6] - datumName - ASCII String with Datum Mnemonic
8 R8 - majA m Semi-major Axis ( accepted range = 6,300,000.0
to 6,500,000.0 metres ).
16 R8 - flat - 1.0 / Flattening ( accepted range is 0.0 to 500.0
).
24 R4 - dX m X Axis shift at the origin ( accepted range is +/-
5000.0 metres ).
28 R4 - dY m Y Axis shift at the origin ( accepted range is +/-
5000.0 metres ).
32 R4 - dZ m Z Axis shift at the origin ( accepted range is +/-
5000.0 metres ).
36 R4 - rotX s Rotation about the X Axis ( accepted range is
+/- 20.0 milli-arc seconds ).
40 R4 - rotY s Rotation about the Y Axis ( accepted range is
+/- 20.0 milli-arc seconds ).
44 R4 - rotZ s Rotation about the Z Axis ( accepted range is +/-
20.0 milli-arc seconds ).
48 R4 - scale ppm Scale change ( accepted range is 0.0 to 50.0
parts per million ).
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CFG-TP (0x06 0x07)
Poll TimePulse Parameters
Message CFG-TP
Description Poll TimePulse Parameters
Type Poll Request
Comment Sending this (empty / no-payload) message to the receiver results in the receiver returning a
message of type CFG-TP with a payload as defined below
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x06 0x07 0 see below CK_A CK_B
No payload
Get/Set TimePulse Parameters
Message CFG-TP
Description Get/Set TimePulse Parameters
Type Get/Set
Comment -
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x06 0x07 20 see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 U4 - interval us Time interval for time pulse
4 U4 - length us Length of time pulse
8 I1 - status - Time pulse config setting
+1 = positive
0 = off
-1 = negative
9 U1 - timeRef - Alignment to reference time:
0 = UTC time,
1 = GPS time
2 = Local time
10 U1 - flags - Bitmask (see graphic below)
11 U1 - res - Reserved
12 I2 - antennaCableD
elay
ns Antenna Cable Delay
14 I2 - rfGroupDelay ns Receiver RF Group Delay
16 I4 - userDelay ns User Time Function Delay (positive delay results
in earlier pulse)
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Bitfield flags
This Graphic explains the bits of flags
Name Description
syncMode 0=Time pulse always synchronized and only available if time is valid
1=Time pulse allowed to be asynchronized and available even when time is not valid
CFG-RATE (0x06 0x08)
Poll Navigation/Measurement Rate Settings
Message CFG-RATE
Description Poll Navigation/Measurement Rate Settings
Type Poll Request
Comment Sending this (empty / no-payload) message to the receiver results in the receiver returning a
message of type CFG-RATE with a payload as defined below
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x06 0x08 0 see below CK_A CK_B
No payload
Navigation/Measurement Rate Settings
Message CFG-RATE
Description Navigation/Measurement Rate Settings
Type Get/Set
Comment The u-blox positioning technology supports navigation update rates higher or lower than 1
update per second. The calculation of the navigation solution will always be aligned to the
top of a second.
•The update rate has a direct influence on the power consumption. The more fixes that
are required, the more CPU power and communication resources are required.
• For most applications a 1 Hz update rate would be sufficient.
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x06 0x08 6 see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 U2 - measRate ms Measurement Rate, GPS measurements are
taken every measRate milliseconds
2 U2 - navRate cycles Navigation Rate, in number of measurement
cycles. On u-blox 5, this parameter cannot be
changed, and is always equals 1.
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CFG-RATE continued
Byte Offset Number
Format
Scaling Name Unit Description
4 U2 - timeRef - Alignment to reference time: 0 = UTC time, 1 =
GPS time
CFG-CFG (0x06 0x09)
Clear, Save and Load configurations
Message CFG-CFG
Description Clear, Save and Load configurations
Type Command
Comment See the Receiver Configuration chapter for a detailed description on how Receiver
Configuration should be used.The three masks are made up of individual bits, each bit
indicating the sub-section of all configurations on which the corresponding action shall be
carried out. Please note that commands can be combined. The sequence of execution is
Clear, Save, Load
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x06 0x09 (12) or (13) see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 X4 - clearMask - Mask with configuration sub-sections to Clear
(=Load Default Configurations to Permanent
Configurations in non-volatile memory) (see
graphic below)
4 X4 - saveMask - Mask with configuration sub-section to Save
(=Save Current Configuration to Non-volatile
Memory), see ID description of clearMask
8 X4 - loadMask - Mask with configuration sub-sections to Load
(=Load Permanent Configurations from
Non-volatile Memory to Current
Configurations), see ID description of clearMask
Start of optional block
12 X1 - deviceMask - Mask which selects the devices for this
command. (see graphic below)
End of optional block
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Bitfield clearMask
This Graphic explains the bits of clearMask
Name Description
ioPort I/O Port Assignements, Protocols and Baud Rates (See messages UBX-CFG-PRT and UBX-CFG-USB)
msgConf Message Configuration (See message UBX-CFG-MSG)
infMsg INF Message Configuration (See UBX-CFG-INF)
navConf NAV Configuration (See UBX-CFG-DAT, UBX-CFG-NAV5, UBX-CFG-RATE, UBX-CFG-SBAS,
UBX-CFG-NMEA, UBX-CFG-TMODE)
tpConf Timepulse Configuration (See UBX-CFG-TP)
antConf Used for Receiver Model-specific settings (e.g. UBX-CFG-ANT)
Bitfield deviceMask
This Graphic explains the bits of deviceMask
Name Description
devBBR device battery backed RAM
devFlash device Flash
devEEPROM device EEPROM
CFG-RXM (0x06 0x11)
RXM configuration
Message CFG-RXM
Description RXM configuration
Type Set/Get
Comment This message is support with firmware 4.01 or later.
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x06 0x11 2 see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 U1 - reserved - reserved
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CFG-RXM continued
Byte Offset Number
Format
Scaling Name Unit Description
1 U1 - lpMode - Low Power Mode
0: Max. performance mode
1-3: reserved
4: Eco mode
5-255: reserved
CFG-ANT (0x06 0x13)
Poll Antenna Control Settings
Message CFG-ANT
Description Poll Antenna Control Settings
Type Poll Request
Comment Sending this (empty / no-payload) message to the receiver results in the receiver returning a
message of type CFG-ANT with a payload as defined below
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x06 0x13 0 see below CK_A CK_B
No payload
Get/Set Antenna Control Settings
Message CFG-ANT
Description Get/Set Antenna Control Settings
Type Get/Set
Comment -
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x06 0x13 4 see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 X2 - flags - Antenna Flag Mask (see graphic below)
2 X2 - pins - Antenna Pin Configuration (see graphic below)
Bitfield flags
This Graphic explains the bits of flags
Name Description
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Bitfield flags Description continued
Name Description
svcs Enable Antenna Supply Voltage Control Signal
scd Enable Short Circuit Detection
ocd Enable Open Circuit Detection
pdwnOnSCD Power Down Antenna supply if Short Circuit is detected. (only in combination with Bit 1)
recovery Enable automatic recovery from short state
Bitfield pins
This Graphic explains the bits of pins
Name Description
pinSwitch PIO-Pin used for switching antenna supply (internal to TIM-LP/TIM-LF)
pinSCD PIO-Pin used for detecting a short in the antenna supply
pinOCD PIO-Pin used for detecting open/not connected antenna
reconfig if set to one, and this command is sent to the receiver, the receiver will reconfigure the pins as specified.
CFG-SBAS (0x06 0x16)
SBAS Configuration
Message CFG-SBAS
Description SBAS Configuration
Type Command
Comment This message configures the SBAS receiver subsystem (i.e. WAAS, EGNOS, MSAS).See the
SBAS Configuration Settings Description for a detailed description of how these settings
affect receiver operation.
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x06 0x16 8 see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 X1 - mode - SBAS Mode (see graphic below)
1 X1 - usage - SBAS Usage (see graphic below)
2 U1 - maxSBAS - Maximum Number of SBAS prioritized tracking
channels (valid range: 0 - 3) to use
3 X1 - scanmode2 - Continuation of scanmode bitmask below (see
graphic below)
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CFG-SBAS continued
Byte Offset Number
Format
Scaling Name Unit Description
4 X4 - scanmode1 - Which SBAS PRN numbers to search for
(Bitmask)
If all Bits are set to zero, auto-scan (i.e. all valid
PRNs) are searched.
Every bit corresponds to a PRN number (see
graphic below)
Bitfield mode
This Graphic explains the bits of mode
Name Description
enabled SBAS Enabled (1) / Disabled (0)
test SBAS Testbed: Use data anyhow (1) / Ignore data when in Test Mode (SBAS Msg 0)
Bitfield usage
This Graphic explains the bits of usage
Name Description
range Use SBAS GEOs as a ranging source (for navigation)
diffCorr Use SBAS Differential Corrections
integrity Use SBAS Integrity Information
Bitfield scanmode2
This Graphic explains the bits of scanmode2
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Bitfield scanmode1
This Graphic explains the bits of scanmode1
CFG-NMEA (0x06 0x17)
Poll the NMEA protocol configuration
Message CFG-NMEA
Description Poll the NMEA protocol configuration
Type Poll Request
Comment -
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x06 0x17 0 see below CK_A CK_B
No payload
Set/Get the NMEA protocol configuration
Message CFG-NMEA
Description Set/Get the NMEA protocol configuration
Type Set/Get
Comment Set/Get the NMEA protocol configuration. See section NMEA Protocol Configuration for a
detailed description of the configuration effects on NMEA output.
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x06 0x17 4 see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 X1 - filter - filter flags (see graphic below)
1 U1 - version - 0x23 = NMEA version 2.3
0x21 = NMEA version 2.1
2 U1 - numSV - Maximum Number of SVs to report in NMEA
protocol.
This does not affect the receiver's operation.
It only limits the number of SVs reported in
NMEA mode (this might be needed with older
mapping applications which only support 8- or
12-channel receivers).
3 X1 - flags - flags (see graphic below)
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Bitfield filter
This Graphic explains the bits of filter
Name Description
posFilt disable position filtering
mskPosFilt disable masked position filtering
timeFilt disable time filtering
dateFilt disable date filtering
sbasFilt enable SBAS filtering
trackFilt disable track filtering
Bitfield flags
This Graphic explains the bits of flags
Name Description
compat enable compatibility mode.
This might be needed for certain applications when customer's NMEA parser expects a fixed number of digits in
position coordinates
consider enable considering mode.
CFG-USB (0x06 0x1B)
Poll a USB configuration
Message CFG-USB
Description Poll a USB configuration
Type Poll Request
Comment -
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x06 0x1B 0 see below CK_A CK_B
No payload
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Get/Set USB Configuration
Message CFG-USB
Description Get/Set USB Configuration
Type Get/Set
Comment -
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x06 0x1B 108 see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 U2 - vendorID - Vendor ID. This field shall only be set to
registered
Vendor IDs. Changing this field requires special
Host drivers.
2 U2 - productID - Product ID. Changing this field requires special
Host drivers.
4 U2 - reserved1 - This field is reserved. Always set to 0
6 U2 - reserved2 - This field is reserved for special use. Always set
to 1
8 U2 - powerConsumpt
ion
- Power consumed by the device in mA
10 X2 - flags - various configuration flags (see graphic below)
12 CH[32] - vendorString - String containing the vendor name. 32 ASCII
bytes including 0-termination.
44 CH[32] - productString - String containing the product name. 32 ASCII
bytes including 0-termination.
76 CH[32] - serialNumber - String containing the serial number. 32 ASCII
bytes including 0-termination.
Changing the String fields requires special Host
drivers.
Bitfield flags
This Graphic explains the bits of flags
Name Description
reEnum force re-enumeration
powerMode self-powered (1), bus-powered (0)
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CFG-TMODE (0x06 0x1D)
Poll Time Mode Settings
Message CFG-TMODE
Description Poll Time Mode Settings
Type Poll Request
Comment This message is available only for timing receivers
Sending this (empty / no-payload) message to the receiver results in the receiver returning a
message of type CFG-TMODE with a payload as defined below
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x06 0x1D 0 see below CK_A CK_B
No payload
Time Mode Settings
Message CFG-TMODE
Description Time Mode Settings
Type Get/Set
Comment This message is available only for timing receivers
See the Time Mode Description for details.
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x06 0x1D 28 see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 U4 - timeMode - Time Transfer Mode:
0  Disabled
1 Survey In
2 Fixed Mode (true position information
required)
3-255 Reserved
4 I4 - fixedPosX cm Fixed Position ECEF X coordinate
8 I4 - fixedPosY cm Fixed Position ECEF Y coordinate
12 I4 - fixedPosZ cm Fixed Position ECEF Z coordinate
16 U4 - fixedPosVar mm^2 Fixed position 3D variance
20 U4 - svinMinDur s Survey-in minimum duration
24 U4 - svinVarLimit mm^2 Survey-in position variance limit
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CFG-NAVX5 (0x06 0x23)
Poll Navigation Engine Expert Settings
Message CFG-NAVX5
Description Poll Navigation Engine Expert Settings
Type Poll Request
Comment Sending this (empty / no-payload) message to the receiver results in the receiver returning a
message of type CFG-NAVX5 with a payload as defined below.
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x06 0x23 0 see below CK_A CK_B
No payload
Get/Set Navigation Engine Expert Settings
Message CFG-NAVX5
Description Get/Set Navigation Engine Expert Settings
Type Get/Set
Comment -
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x06 0x23 40 see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 U2 - version - Message version. Current version is 0.
2 X2 - mask1 - First Parameters Bitmask. Only the flagged
parameters will be applied, unused bits must be
set to 0. (see graphic below)
4 X4 - mask2 - Second Parameters Bitmask. Currently unused,
must be set to 0.
8 U1 - res1 - reserved, set to 0
9 U1 - res2 - reserved, set to 0
10 U1 - minSVs #SVs Minimum number of satellites for navigation
11 U1 - maxSVs #SVs Maximum number of satellites for navigation
12 U1 - minCNO dbHz Minimum satellite signal level for navigation
13 U1 - res3 - reserved, set to 0
14 U1 - iniFix3D - Initial Fix must be 3D flag (0=false/1=true)
15 U1 - res4 - reserved, set to 0
16 U1 - res5 - reserved, set to 0
17 U1 - res6 - reserved, set to 0
18 U2 - wknRollover - GPS week rollover number; GPS week numbers
will be set correctly from this week up to 1024
weeks after this week. Setting this to 0 reverts
to firmware default.
20 U4 - res7 - reserved, set to 0
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CFG-NAVX5 continued
Byte Offset Number
Format
Scaling Name Unit Description
24 U4 - res8 - reserved, set to 0
28 U4 - res9 - reserved, set to 0
32 U4 - res10 - reserved, set to 0
36 U4 - res11 - reserved, set to 0
Bitfield mask1
This Graphic explains the bits of mask1
Name Description
minMax Apply min/max SVs settings
minCno Apply minimum C/N0 setting
3dfix Apply initial 3D fix settings
wknRoll Apply GPS weeknumber rollover settings
CFG-NAV5 (0x06 0x24)
Poll Navigation Engine Settings
Message CFG-NAV5
Description Poll Navigation Engine Settings
Type Poll Request
Comment Sending this (empty / no-payload) message to the receiver results in the receiver returning a
message of type CFG-NAV5 with a payload as defined below.
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x06 0x24 0 see below CK_A CK_B
No payload
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Get/Set Navigation Engine Settings
Message CFG-NAV5
Description Get/Set Navigation Engine Settings
Type Get/Set
Comment See the Navigation Configuration Settings Description for a detailed description of how
these settings affect receiver operation.
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x06 0x24 36 see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 X2 - mask - Parameters Bitmask. Only the masked
parameters will be applied. (see graphic below)
2 U1 - dynModel - Dynamic Platform model:
- 0 Portable
- 2 Stationary
- 3 Pedestrian
- 4 Automotive
- 5 Sea
- 6 Airborne with >1g Acceleration
- 7 Airborne with >2g Acceleration
- 8 Airborne with >4g Acceleration
3 U1 - fixMode - Position Fixing Mode.
- 1: 2D only
- 2: 3D only
- 3: Auto 2D/3D
4 I4 0.01 fixedAlt m Fixed altitude (mean sea level) for 2D fix mode.
8 U4 0.0001 fixedAltVar m^2 Fixed altitude variance for 2D mode.
12 I1 - minElev deg Minimum Elevation for a GNSS satellite to be
used in NAV
13 U1 - drLimit s Maximum time to perform dead reckoning
(linear extrapolation) in case of GPS signal loss
14 U2 0.1 pDop - Position DOP Mask to use
16 U2 0.1 tDop - Time DOP Mask to use
18 U2 - pAcc m Position Accuracy Mask
20 U2 - tAcc m Time Accuracy Mask
22 U1 - staticHoldThr
esh
cm/s Static hold threshold
23 U1 - res1 - reserved, set to 0
24 U4 - res2 - reserved, set to 0
28 U4 - res3 - reserved, set to 0
32 U4 - res4 - reserved, set to 0
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Bitfield mask
This Graphic explains the bits of mask
Name Description
dyn Apply dynamic model settings
minEl Apply minimum elevation settings
fixMode Apply fix mode settings
drLim Apply DR limit settings
posMask Apply position mask settings
timeMask Apply time mask settings
staticHoldMas
k
Apply static hold settings
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MON (0x0A)
Monitoring Messages: i.e. Comunication Status, CPU Load, Stack Usage, Task Status.
Messages in this class are sent to report GPS receiver status, such as CPU load, stack usage, I/O subsystem
statistics etc.
MON-IO (0x0A 0x02)
I/O Subsystem Status
Message MON-IO
Description I/O Subsystem Status
Type Periodic/Polled
Comment The size of the message is determined by the NPRT number of ports the receiver supports, i.
e. on ANTARIS this is always 4, on u-blox 5 the number of ports is 6.
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x0A 0x02 0 + 20*NPRT see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
Start of repeated block (NPRT times)
N*20 U4 - rxBytes bytes Number of bytes ever received
4 + 20*N U4 - txBytes bytes Number of bytes ever sent
8 + 20*N U2 - parityErrs - Number of 100ms timeslots with parity errors
10 + 20*N U2 - framingErrs - Number of 100ms timeslots with framing errors
12 + 20*N U2 - overrunErrs - Number of 100ms timeslots with overrun errors
14 + 20*N U2 - breakCond - Number of 100ms timeslots with break
conditions
16 + 20*N U1 - rxBusy - Flag is receiver is busy
17 + 20*N U1 - txBusy - Flag is transmitter is busy
18 + 20*N U2 - res - reserved
End of repeated block
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MON-VER (0x0A 0x04)
Receiver/Software Version
Message MON-VER
Description Receiver/Software Version
Type Answer to Poll
Comment -
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x0A 0x04 40 + 30*Num see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 CH[30] - swVersion - Zero-terminated Software Version String
30 CH[10] - hwVersion - Zero-terminated Hardware Version String
Start of repeated block (Num times)
40 + 30*N CH[30] - extension - Installed Extension Package Version
End of repeated block
MON-MSGPP (0x0A 0x06)
Message Parse and Process Status
Message MON-MSGPP
Description Message Parse and Process Status
Type Periodic/Polled
Comment -
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x0A 0x06 120 see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 U2[8] - msg1 msgs Number of successfully parsed messages for
each protocol on target0
16 U2[8] - msg2 msgs Number of successfully parsed messages for
each protocol on target1
32 U2[8] - msg3 msgs Number of successfully parsed messages for
each protocol on target2
48 U2[8] - msg4 msgs Number of successfully parsed messages for
each protocol on target3
64 U2[8] - msg5 msgs Number of successfully parsed messages for
each protocol on target4
80 U2[8] - msg6 msgs Number of successfully parsed messages for
each protocol on target5
96 U4[6] - skipped bytes Number skipped bytes for each target
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MON-RXBUF (0x0A 0x07)
Receiver Buffer Status
Message MON-RXBUF
Description Receiver Buffer Status
Type Periodic/Polled
Comment -
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x0A 0x07 24 see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 U2[6] - pending bytes Number of bytes pending in receiver buffer for
each target
12 U1[6] - usage % Maximum usage receiver buffer during the last
sysmon period for each target
18 U1[6] - peakUsage % Maximum usage receiver buffer for each target
MON-TXBUF (0x0A 0x08)
Transmitter Buffer Status
Message MON-TXBUF
Description Transmitter Buffer Status
Type Periodic/Polled
Comment -
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x0A 0x08 28 see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 U2[6] - pending bytes Number of bytes pending in transmitter buffer
for each target
12 U1[6] - usage % Maximum usage transmitter buffer during the
last sysmon period for each target
18 U1[6] - peakUsage % Maximum usage transmitter buffer for each
target
24 U1 - tUsage % Maximum usage of transmitter buffer during
the last sysmon period for all targets
25 U1 - tPeakusage % Maximum usage of transmitter buffer for all
targets
26 X1 - errors - Error bitmask (see graphic below)
27 U1 - res - reserved
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Bitfield errors
This Graphic explains the bits of errors
Name Description
limit Buffer limit of corresponding target reached
mem Memory Allocation error
alloc Allocation error (TX buffer full)
MON-HW (0x0A 0x09)
Hardware Status
Message MON-HW
Description Hardware Status
Type Periodic/Polled
Comment Status of different aspect of the hardware, such as Antenna, PIO/Peripheral Pins, Noise
Level, Automatic Gain Control (AGC)
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x0A 0x09 68 see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 X4 - pinSel - Mask of Pins Set as Peripheral/PIO
4 X4 - pinBank - Mask of Pins Set as Bank A/B
8 X4 - pinDir - Mask of Pins Set as Input/Output
12 X4 - pinVal - Mask of Pins Value Low/High
16 U2 - noisePerMS - Noise Level as measured by the GPS Core
18 U2 - agcCnt - AGC Monitor (counts SIGHI xor SIGLO, range 0
to 8191)
20 U1 - aStatus - Status of the Antenna Supervisor State Machine
(0=INIT, 1=DONTKNOW, 2=OK, 3=SHORT,
4=OPEN)
21 U1 - aPower - Current PowerStatus of Antenna (0=OFF, 1=ON,
2=DONTKNOW)
22 X1 - flags - Flags (see graphic below)
23 U1 - res1 - Reserved
24 X4 - usedMask - Mask of Pins that are used by the Virtual Pin
Manager
28 U1[25] - VP - Array of Pin Mappings for each of the 25
Physical Pins
53 U1[3] - res2 - Reserved
56 X4 - pinIrq - Mask of Pins Value using the PIO Irq
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MON-HW continued
Byte Offset Number
Format
Scaling Name Unit Description
60 X4 - pullH - Mask of Pins Value using the PIO Pull High
Resistor
64 X4 - pullL - Mask of Pins Value using the PIO Pull Low
Resistor
Bitfield flags
This Graphic explains the bits of flags
Name Description
rtcCalib RTC is calibrated
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AID (0x0B)
AssistNow Aiding Messages: i.e. Ephemeris, Almanac, other A-GPS data input.
Messages in this class are used to send aiding data to the receiver.
AID-REQ (0x0B 0x00)
Sends a poll (AID-DATA) for all GPS Aiding Data
Message AID-REQ
Description Sends a poll (AID-DATA) for all GPS Aiding Data
Type Virtual
Comment AID-REQ is not a message but a placeholder for configuration purposes.
If the virtual AID-REQ is configured to be output (see CFG-MSG), the receiver will output a
request for aiding data (AID-DATA) after a start-up if its internally stored data (position,
time, ephemeris, almanac) don't allow it to perform a hot start.
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x0B 0x00 0 see below CK_A CK_B
No payload
AID-INI (0x0B 0x01)
Poll GPS Initial Aiding Data
Message AID-INI
Description Poll GPS Initial Aiding Data
Type Poll Request
Comment This message has an empty payload!
-
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x0B 0x01 0 see below CK_A CK_B
No payload
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Aiding position, time, frequency, clock drift
Message AID-INI
Description Aiding position, time, frequency, clock drift
Type Polled
Comment This message contains position, time and clock drift information. The position can be input
in either the ECEF X/Y/Z coordinate system or as lat/lon/height. The time can either be input
as inexact value via the standard communication interface, suffering from latency
depending on the baudrate, or using harware time synchronization where an accuracte
time pulse is input on the external interrupts. It is also possible to supply hardware
frequency aiding by connecting a continuous signal to an external interrupt.
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x0B 0x01 48 see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 I4 - ecefXOrLat cm_or_
deg*1e
7
WGS84 ECEF X coordinate or latitude,
depending on flags below
4 I4 - ecefYOrLon cm_or_
deg*1e
7
WGS84 ECEF Y coordinate or longitude,
depending on flags below
8 I4 - ecefZOrAlt cm WGS84 ECEF Z coordinate or altitude,
depending on flags below
12 U4 - posAcc cm Position accuracy (stddev)
16 X2 - tmCfg - Time mark configuration (see graphic below)
18 U2 - wn - Actual week number
20 U4 - tow ms Actual time of week
24 I4 - towNs ns Sub-millisecond part of time of week
28 U4 - tAccMs ms Milliseconds part of time accuracy
32 U4 - tAccNs ns Nanoseconds part of time accuracy
36 I4 - clkDOrFreq ns/s_or
_Hz
Clock drift or frequency, depending on flags
below
40 U4 - clkDAccOrFreq
Acc
ns/s_or
_ppm
Accuracy of clock drift or frequency, depending
on flags below
44 X4 - flags - Bitmask with the following flags (see graphic
below)
Bitfield tmCfg
This Graphic explains the bits of tmCfg
Name Description
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Bitfield tmCfg Description continued
Name Description
fEdge use falling edge (default rising)
tm1 time mark on extint 1 (default extint 0)
f1 frequency on extint 1 (default extint 0)
Bitfield flags
This Graphic explains the bits of flags
Name Description
pos Position is valid
time Time is valid
clockD Clock drift data contains valid clock drift, must not be set together with clockF
tp Use time pulse
clockF Clock drift data contains valid frequency, must not be set together with clockD
lla Position is given in LAT/LON/ALT (default is ECEF)
altInv Altitude is not valid, in case lla was set
prevTm Use time mark received before AID-INI message (default uses mark received after message)
AID-HUI (0x0B 0x02)
Poll GPS Health, UTC and ionosphere parameters
Message AID-HUI
Description Poll GPS Health, UTC and ionosphere parameters
Type Poll Request
Comment This message has an empty payload!
-
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x0B 0x02 0 see below CK_A CK_B
No payload
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GPS Health, UTC and ionosphere parameters
Message AID-HUI
Description GPS Health, UTC and ionosphere parameters
Type Input/Output Message
Comment This message contains a health bit mask, UTC time and Klobuchar parameters. For more
information on these parameters, please see the ICD-GPS-200 documentation.
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x0B 0x02 72 see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 X4 - health - Bitmask, every bit represenst a GPS SV (1-32). If
the bit is set the SV is healthy.
4 R8 - utcA1 - UTC - parameter A1
12 R8 - utcA0 - UTC - parameter A0
20 I4 - utcTOW - UTC - reference time of week
24 I2 - utcWNT - UTC - reference week number
26 I2 - utcLS - UTC - time difference due to leap seconds
before event
28 I2 - utcWNF - UTC - week number when next leap second
event occurs
30 I2 - utcDN - UTC - day of week when next leap second event
occurs
32 I2 - utcLSF - UTC - time difference due to leap seconds after
event
34 I2 - utcSpare - UTC - Spare to ensure structure is a multiple of
4 bytes
36 R4 - klobA0 s Klobuchar - alpha 0
40 R4 - klobA1 s/semici
rcle
Klobuchar - alpha 1
44 R4 - klobA2 s/semici
rcle^2
Klobuchar - alpha 2
48 R4 - klobA3 s/semici
rcle^3
Klobuchar - alpha 3
52 R4 - klobB0 s Klobuchar - beta 0
56 R4 - klobB1 s/semici
rcle
Klobuchar - beta 1
60 R4 - klobB2 s/semici
rcle^2
Klobuchar - beta 2
64 R4 - klobB3 s/semici
rcle^3
Klobuchar - beta 3
68 X4 - flags - flags (see graphic below)
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Bitfield flags
This Graphic explains the bits of flags
Name Description
health Healthmask field in this message is valid
utc UTC parameter fields in this message are valid
klob Klobuchar parameter fields in this message are valid
AID-DATA (0x0B 0x10)
Polls all GPS Initial Aiding Data
Message AID-DATA
Description Polls all GPS Initial Aiding Data
Type Poll
Comment If this poll is received, the messages AID-INI, AID-HUI, AID-EPH and AID-ALM are sent.
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x0B 0x10 0 see below CK_A CK_B
No payload
AID-ALM (0x0B 0x30)
Poll GPS Aiding Almanach Data
Message AID-ALM
Description Poll GPS Aiding Almanach Data
Type Poll Request
Comment This message has an empty payload!
Poll GPS Aiding Data (Almanach) for all 32 SVs by sending this message to the receiver
without any payload. The receiver will return 32 messages of type AID-ALM as defined
below.
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x0B 0x30 0 see below CK_A CK_B
No payload
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Poll GPS Aiding Almanach Data for a SV
Message AID-ALM
Description Poll GPS Aiding Almanach Data for a SV
Type Poll Request
Comment Poll GPS Aiding Data (Almanach) for an SV by sending this message to the receiver. The
receiver will return one message of type AID-ALM as defined below.
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x0B 0x30 1 see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 U1 - svid - SV ID for which the receiver shall return
its Almanach Data (Valid Range: 1 .. 32 or 51,
56, 63).
GPS Aiding Almanach Input/Output Message
Message AID-ALM
Description GPS Aiding Almanach Input/Output Message
Type Input/Output Message
Comment •If the WEEK Value is 0, DWRD0 to DWRD7 are not sent as the almanach is not available
for the given SV.
•DWORD0 to DWORD7 contain the 8 words following the Hand-Over Word ( HOW )
from the GPS navigation message, either pages 1 to 24 of sub-frame 5 or pages 2 to 10
of subframe 4. See IS-GPS-200 for a full description of the contents of the Almanac
pages.
•In DWORD0 to DWORD7, the parity bits have been removed, and the 24 bits of data are
located in Bits 0 to 23. Bits 24 to 31 shall be ignored.
•Example: Parameter e (Eccentricity) from Almanach Subframe 4/5, Word 3, Bits 69-84
within the subframe can be found in DWRD0, Bits 15-0 whereas Bit 0 is the LSB.
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x0B 0x30 (8) or (40) see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 U4 - svid - SV ID for which this
Almanach Data is (Valid Range: 1 .. 32 or 51,
56, 63).
4 U4 - week - Issue Date of Almanach (GPS week number)
Start of optional block
8 U4[8] - dwrd - Almanach Words
End of optional block
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AID-EPH (0x0B 0x31)
Poll GPS Aiding Ephemeris Data
Message AID-EPH
Description Poll GPS Aiding Ephemeris Data
Type Poll Request
Comment This message has an empty payload!
Poll GPS Aiding Data (Ephemeris) for all 32 SVs by sending this message to the receiver
without any payload. The receiver will return 32 messages of type AID-EPH as defined
below.
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x0B 0x31 0 see below CK_A CK_B
No payload
Poll GPS Aiding Ephemeris Data for a SV
Message AID-EPH
Description Poll GPS Aiding Ephemeris Data for a SV
Type Poll Request
Comment Poll GPS Constellation Data (Ephemeris) for an SV by sending this message to the receiver.
The receiver will return one message of type AID-EPH as defined below.
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x0B 0x31 1 see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 U1 - svid - SV ID for which the receiver shall return
its Ephemeris Data (Valid Range: 1 .. 32).
GPS Aiding Ephemeris Input/Output Message
Message AID-EPH
Description GPS Aiding Ephemeris Input/Output Message
Type Input/Output Message
Comment •SF1D0 to SF3D7 is only sent if ephemeris is available for this SV. If not, the payload may
be reduced to 8 Bytes, or all bytes are set to zero, indicating that this SV Number does
not have valid ephemeris for the moment.
•SF1D0 to SF3D7 contain the 24 words following the Hand-Over Word ( HOW ) from the
GPS navigation message, subframes 1 to 3. See IS-GPS-200 for a full description of the
contents of the Subframes.
•In SF1D0 to SF3D7, the parity bits have been removed, and the 24 bits of data are
located in Bits 0 to 23. Bits 24 to 31 shall be ignored.
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x0B 0x31 (8) or (104) see below CK_A CK_B
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Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 U4 - svid - SV ID for which this ephemeris data is
(Valid Range: 1 .. 32).
4 U4 - how - Hand-Over Word of first Subframe. This is
required if data is sent to the receiver.
0 indicates that no Ephemeris Data is following.
Start of optional block
8 U4[8] - sf1d - Subframe 1 Words 3..10 (SF1D0..SF1D7)
40 U4[8] - sf2d - Subframe 2 Words 3..10 (SF2D0..SF2D7)
72 U4[8] - sf3d - Subframe 3 Words 3..10 (SF3D0..SF3D7)
End of optional block
AID-ALPSRV (0x0B 0x32)
ALP client requests AlmanacPlus data from server
Message AID-ALPSRV
Description ALP client requests AlmanacPlus data from server
Type Output Message
Comment This message is sent by the ALP client to the ALP server in order to request data. The given
identifier must be prepended to the requested data when submitting the data.
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x0B 0x32 16 see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 U1 - idSize bytes Identifier size. This data, beginning at message
start, must prepend the returned data.
1 U1 - type - Requested data type. Must be different from
0xff, otherwise this is not a data request.
2 U2 - ofs - Requested data offset [16bit words]
4 U2 - size - Requested data size [16bit words]
6 U2 - fileId - Unused when requesting data, filled in when
sending back the data
8 U2 - dataSize bytes Actual data size. Unused when requesting data,
filled in when sending back the data.
10 U1 - id1 - Identifier data
11 U1 - id2 - Identifier data
12 U4 - id3 - Identifier data
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ALP server sends AlmanacPlus data to client
Message AID-ALPSRV
Description ALP server sends AlmanacPlus data to client
Type Input Message
Comment This message is sent by the ALP server to the ALP client and is usually sent in response to a
data request. The server copies the identifier from the request and fills in the dataSize and
fileId fields.
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x0B 0x32 16 + 1*dataSize see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 U1 - idSize bytes Identifier size
1 U1 - type - Requested data type
2 U2 - ofs - Requested data offset [16bit words]
4 U2 - size - Requested data size [16bit words]
6 U2 - fileId - Corresponding ALP file ID, must be filled in by
the server!
8 U2 - dataSize bytes Actual data contained in this message, must be
filled in by the server!
10 U1 - id1 - Identifier data
11 U1 - id2 - Identifier data
12 U4 - id3 - Identifier data
Start of repeated block (dataSize times)
16 + 1*N U1 - data - Data for the ALP client
End of repeated block
ALP client sends AlmanacPlus data to server.
Message AID-ALPSRV
Description ALP client sends AlmanacPlus data to server.
Type Output Message
Comment This message is sent by the ALP client to the ALP server in order to submit updated data.
The server can either replace the current data at this position or ignore this new data
(which will result in degraded performance).
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x0B 0x32 8 + 2*size see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 U1 - idSize bytes Identifier size
1 U1 - type - Set to 0xff to mark that is *not* a data request
2 U2 - ofs - Data offset [16bit words]
4 U2 - size - Data size [16bit words]
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AID-ALPSRV continued
Byte Offset Number
Format
Scaling Name Unit Description
6 U2 - fileId - Corresponding ALP file id
Start of repeated block (size times)
8 + 2*N U2 - data - 16bit word data to be submitted to the ALP
server
End of repeated block
AID-ALP (0x0B 0x50)
ALP file data transfer to the receiver
Message AID-ALP
Description ALP file data transfer to the receiver
Type Input message
Comment This message is used to transfer a chunk of data from the AlmanacPlus file to the receiver.
Upon reception of this message, the receiver will write the payload data to its internal
non-volatile memory, eventually also erasing that part of the memory first. Make sure that
the payload size is even sized (i.e. always a multiple of 2). Do not use payloads larger than
~ 700 bytes, as this would exceed the receiver’s internal buffering capabilities. The receiver
will (not-) acknowledge this message using the message alternatives given below. The host
shall wait for an acknowledge message before sending the next chunk.
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x0B 0x50 0 + 2*Variable see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
Start of repeated block (Variable times)
N*2 U2 - alpData - ALP file data
End of repeated block
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Mark end of data transfer
Message AID-ALP
Description Mark end of data transfer
Type Input message
Comment This message is used to indicate that all chunks have been transferred, and normal receiver
operation can resume. Upon reception of this message, the receiver will verify all chunks
received so far, and enable AssistNow Offline and GPS receiver operation if successful. This
message could also be sent to cancel an incomplete download.
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x0B 0x50 1 see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 U1 - dummy - Value is ignored
Acknowledges a data transfer
Message AID-ALP
Description Acknowledges a data transfer
Type Output message
Comment This message from the receiver acknowledges successful processing of a previously received
chunk of data with the “Chunk Transfer” Message. This message will also be sent once a
“Stop” message has been received, and the integrity of all chunks received so far has been
checked successfully.
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x0B 0x50 1 see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 U1 - ack - Set to 0x01
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Indicate problems with a data transfer
Message AID-ALP
Description Indicate problems with a data transfer
Type Output message
Comment This message from the receiver indicates that an error has occurred while processing and
storing the data received with the “Chunk Transfer” message. This message will also be
sent once a stop command has been received, and the integrity of all chunks received
failed.
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x0B 0x50 1 see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 U1 - nak - Set to 0x00
Poll the AlmanacPlus status
Message AID-ALP
Description Poll the AlmanacPlus status
Type Periodic/Polled
Comment -
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x0B 0x50 24 see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 U4 - predTow s Prediction start time of week
4 U4 - predDur s Prediction duration from start of first data set to
end of last data set
8 I4 - age s Current age of ALP data
12 U2 - predWno - Prediction start week number
14 U2 - almWno - Truncated week number of reference almanac
16 U4 - res1 - Reserved for future use
20 U1 - svs - Number of satellite data sets contained in the
ALP data
21 U1 - res2 - Reserved for future use
22 U1 - res3 - Reserved for future use
23 U1 - res4 - Reserved for future use
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TIM (0x0D)
Timing Messages: i.e. Timepulse Output, Timemark Results.
Messages in this class are output by the receiver, giving information on Timepulse and Timemark
measurements.
TIM-TP (0x0D 0x01)
Timepulse Timedata
Message TIM-TP
Description Timepulse Timedata
Type Periodic/Polled
Comment This message contains information for high precision timing. Note that contents are correct
only if the timepulse is set to one pulse per second.
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x0D 0x01 16 see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 U4 - towMS ms Timepulse time of week according to time base
4 U4 2^-32 towSubMS ms Submillisecond part of TOWMS
8 I4 - qErr ps Quantization error of timepulse.
12 U2 - week weeks Timepulse week number according to time base
14 X1 - flags - bitmask (see graphic below)
15 U1 - res - unused
Bitfield flags
This Graphic explains the bits of flags
Name Description
timeBase 0=Time base is GPS
1=Time base is UTC
utc 0=UTC not available
1=UTC available
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TIM-TM2 (0x0D 0x03)
Time mark data
Message TIM-TM2
Description Time mark data
Type Periodic/Polled
Comment This message contains information for high precision time stamping / pulse counting.
The delay figures given in CFG-TP are also applied to the time results output in this
message.
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x0D 0x03 28 see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 U1 - ch time marker channel 0 or 1
1 X1 - flags - Bitmask (see graphic below)
2 U2 - count - edge counter.
4 U2 - wnR - week number of last rising edge
6 U2 - wnF - week number of last falling edge
8 U4 - towMsR ms tow of rising edge
12 U4 - towSubMsR ns millisecond fraction of tow of rising edge in
nanoseconds
16 U4 - towMsF ms tow of falling edge
20 U4 - towSubMsF ns millisecond fraction of tow of falling edge in
nanoseconds
24 U4 - accEst ns Accuracy estimate
Bitfield flags
This Graphic explains the bits of flags
Name Description
mode 0=single
1=running
run 0=armed
1=stopped
newFallingEdg
e
new falling edge detected
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Bitfield flags Description continued
Name Description
timeBase 0=Time base is Receiver Time
1=Time base is GPS
2=Time base is UTC
utc 0=UTC not available
1=UTC available
time 0=Time is not valid
1=Time is valid (Valid GPS fix)
newRisingEdge new rising edge detected
TIM-SVIN (0x0D 0x04)
Survey-in data
Message TIM-SVIN
Description Survey-in data
Type Periodic/Polled
Comment This message is only supported on timing receivers
This message contains information about survey-in parameters. For details about the Time
Mode see section Time Mode Configuration.
Header ID Length (Bytes) Payload Checksum
Message Structure 0xB5 0x62 0x0D 0x04 28 see below CK_A CK_B
Payload Contents:
Byte Offset Number
Format
Scaling Name Unit Description
0 U4 - dur s Passed survey-in observation time
4 I4 - meanX cm Current survey-in mean position ECEF X
coordinate
8 I4 - meanY cm Current survey-in mean position ECEF Y
coordinate
12 I4 - meanZ cm Current survey-in mean position ECEF Z
coordinate
16 U4 - meanV mm^2 Current survey-in mean position 3D variance
20 U4 - obs - Observations used during survey-in
24 U1 - valid - Survey-in position validity flag
25 U1 - active - Survey-in in progress flag
26 U2 - reserved - Reserved
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Appendix
u-blox 5 Default Settings
The default settings listed in this section apply to u-blox 5 ROM-based receivers with ROM version 4.0. These
values assume that the default levels of the configuration pins have been left unchanged. Default settings are
dependent on the configuration pin settings, for information regarding these settings, consult the applicable
Data Sheet.
Antenna Supervisor Settings (UBX-CFG-ANT)
For parameter and protocol description see section UBX-CFG-ANT.
Antenna Settings
Parameter Default Setting Unit
Enable Control Signal Enabled
Enable Short Circuit Detection Enabled
Enable Short Circuit Power Down logic Enabled
Enable Automatic Short Circuit Recovery logic Enabled
Enable Open Circuit Detection Disabled
Datum Settings (UBX-CFG-DAT)
For parameter and protocol description see section UBX-CFG-DAT.
Datum Default Settings
Parameter Default Setting Unit
Datum 0 – WGS84
Navigation Settings (UBX-CFG-NAV5)
For parameter and protocol description see section UBX-CFG-NAV5.
Navigation Default Settings
Parameter Default Setting Unit
Dynamic Platform Model 0 – Portable
Fix Mode Auto 2D/3D #
Fixed Altitude N/A m
Fixed Altitude Variance N/A m^2
Min SV Elevation 5 deg
DR Timeout 0 s
PDOP Mask 25 -
TDOP Mask 25 -
P Accuracy 100 m
T Accuracy 300 m
Static Hold Threshold 0.00 m/s
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Output Rates (UBX-CFG-RATE)
For parameter and protocol description see section UBX-CFG-RATE.
Output Rate Default Settings
Parameter Default Setting Unit
Time Source 1 – GPS time
Measurement Period 1000 ms
Measurement Rate 1 Cycles
SBAS Configuration (UBX-CFG-SBAS)
For parameter and protocol description see section UBX-CFG-SBAS.
SBAS Configuration Default Settings
Parameter Default Setting Unit
SBAS Subsystem Enabled
Allow test mode usage Disabled
Ranging (Use SBAS for navigation) Enabled
Apply SBAS Correction Data Enabled
Apply integrity information Disabled
Number of search channels 3
PRN Codes 120, 122, 124, 126-127, 129, 131, 134-135, 137-138
Port Setting (UBX-CFG-PRT)
For parameter and protocol description see section UBX-CFG-PRT.
Port Default Settings
Parameter Default Setting Unit
DDC/I2C (Target0)
Protocol in 0+1 – UBX+NMEA
Protocol out 0+1 – UBX+NMEA
USART1 (Target1)
Protocol in 0+1 – UBX+NMEA
Protocol out 0+1 – UBX+NMEA
Baudrate 9600 baud
USART2 (Target2)
Protocol in None
Protocol out None
Baudrate 9600 baud
USB (Target3)
Protocol in 0+1 – UBX+NMEA
Protocol out 0+1 – UBX+NMEA
SPI (Target4)
Protocol in 0+1 – UBX+NMEA
Protocol out 0+1 – UBX+NMEA
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Port Setting (UBX-CFG-USB)
For parameter and protocol description see section UBX-CFG-USB.
USB default settings
Parameter Default Setting Unit
Power Mode
Power Mode Bus powered
Bus Current required 120 mA
Message Settings (UBX-CFG-MSG)
For parameter and protocol description see section UBX-CFG-MSG.
Enabled output messages
Message Type All Targets
NMEA - GGA Out 1
NMEA - GLL Out 1
NMEA - GSA Out 1
NMEA - GSV Out 1
NMEA - RMC Out 1
NMEA - VTG Out 1
NMEA Protocol Settings (UBX-CFG-NMEA)
For parameter and protocol description see section UBX-CFG-NMEA.
NMEA Protocol Default Settings
Parameter Default Setting Unit
Enable position output even for invalid fixes Disabled
Enable position even for masked fixes Disabled
Enable time output even for invalid times Disabled
Enable time output even for invalid dates Disabled
Version 2.3
Compatibility Mode Disabled
Consideration Mode Enabled
Number of SV Unlimited
INF Messages Settings (UBX–CFG–INF)
For parameter and protocol description see section UBX-CFG-INF.
NMEA default enabled INF msg
Message Type All Targets Range/Remark
INF-Error Out 1 In NMEA Protocol only (GPTXT)
INF-Warning Out 1 In NMEA Protocol only (GPTXT)
INF-Notice Out 1 In NMEA Protocol only (GPTXT)
INF-Test Out
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NMEA default enabled INF msg continued
Message Type All Targets Range/Remark
INF-Debug Out
INF-User Out 1 In NMEA Protocol only (GPTXT)
Timepulse Settings (UBX–CFG–TP)
For parameter and protocol description see section UBX-CFG-TP.
Timepulse default settings
Parameter Default Setting Unit
Pulse Mode +1 – rising
Pulse Period 1000 ms
Pulse Length 100 ms
Time Source 1 – GPS time
Cable Delay 50 ns
User Delay 0 ns
SyncMode 0 (no time pulse in case of no fix)
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