GPS Hemisphere GNSS Technical Reference Guide V1.09
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Hemisphere GNSS
Technical Reference
Manual
Current Version: v1.09
January 8, 2018
Table of Contents
SBAS Automatic Tracking ................................................................................................ 10
SBAS Performance .......................................................................................................... 11
WAAS .............................................................................................................................. 11
WAAS DGPS ................................................................................................................... 12
WAAS Signal Information ................................................................................................. 14
WAAS Reception ............................................................................................................. 15
WAAS Coverage .............................................................................................................. 16
Radiobeacon Overview .................................................................................................... 20
Radiobeacon Range......................................................................................................... 21
Radiobeacon Reception ................................................................................................... 22
Radiobeacon Antenna Location ....................................................................................... 22
Radiobeacon Coverage.................................................................................................... 23
Atlas Overview ................................................................................................................. 24
Atlas Signal Information ................................................................................................... 25
Atlas Reception ................................................................................................................ 26
Atlas Automatic Tracking .................................................................................................. 27
Atlas Receiver Performance ............................................................................................. 28
Crescent Base Station Overview ...................................................................................... 29
Crescent Base Station Startup ......................................................................................... 30
Crescent Base Station Calibration .................................................................................... 31
Crescent Base Station Performance ................................................................................ 32
About Firmware ................................................................................................................ 53
Using RightARM to Load Firmware .................................................................................. 54
Subscribing to an Application ........................................................................................... 59
Interpreting the $JK 'Date'/Subscription Codes................................................................. 61
Understanding Additive Codes ......................................................................................... 62
Comparing the JI and JK Responses ............................................................................... 64
Eclipse II Subscription Codes ........................................................................................... 65
Determining the Receiver Type and Current Application .................................................. 72
'THIS' Port and the 'OTHER' Port ..................................................................................... 74
Enabling Database Mode ................................................................................................. 77
Performance in Database Mode ....................................................................................... 77
Available Production Configuration Settings ..................................................................... 77
Enabling and Disabling Ethernet ...................................................................................... 78
Enabling Ethernet Services .............................................................................................. 78
Message Structure ......................................................................................................... 101
Messages....................................................................................................................... 101
JASC Command Overview ................................................................................................................................................ 115
JASC,CMR Command ....................................................................................................................................................... 116
JASC,D1 Command ........................................................................................................................................................... 117
JASC,DFX Command ........................................................................................................................................................ 119
JASC,GL Command .......................................................................................................................................................... 120
JASC,GA Command .......................................................................................................................................................... 122
JASC,GQ Command .......................................................................................................................................................... 124
JASC,GN Command .......................................................................................................................................................... 126
JASC,GP Command .......................................................................................................................................................... 127
JASC,INTLT Command ..................................................................................................................................................... 129
JASC,PASHR Command ................................................................................................................................................... 130
JASC,PSAT,ATTSTAT Command ..................................................................................................................................... 132
JASC,PSAT,BLV Command .............................................................................................................................................. 133
JASC,PSAT,FVI Command ............................................................................................................................................... 134
JASC,PSAT,RTKPROG Command ................................................................................................................................... 135
JASC,PSAT,RTKSTAT Command..................................................................................................................................... 137
JASC,PSAT,VCT Command .............................................................................................................................................. 138
JASC,PTSS1 Command .................................................................................................................................................... 139
JASC,ROX Command ........................................................................................................................................................ 141
JASC,RTCM Command ..................................................................................................................................................... 142
JASC,RTCM3 Command ................................................................................................................................................... 143
JASC,VIRTUAL Command ................................................................................................................................................ 145
JATT ................................................................................................................................................................................... 146
JATT Command Overview ................................................................................................................................................ 146
JATT,COGTAU Command................................................................................................................................................. 147
JATT,CSEP Command ...................................................................................................................................................... 148
JATT,EXACT Command .................................................................................................................................................... 149
JATT,FLIPBRD Command................................................................................................................................................. 150
JATT,GYROAID Command ............................................................................................................................................... 151
JATT,HBIAS Command ..................................................................................................................................................... 153
JATT,HELP Command ...................................................................................................................................................... 154
JATT,HIGHMP Command .................................................................................................................................................. 155
JATT,HRTAU Command.................................................................................................................................................... 156
JATT,HTAU Command ...................................................................................................................................................... 158
JATT,LEVEL Command..................................................................................................................................................... 159
JATT,MOVEBASE Command ............................................................................................................................................ 160
JATT,MSEP Command ...................................................................................................................................................... 161
JATT,NEGTILT Command ................................................................................................................................................. 162
JATT,NMEAHE Command................................................................................................................................................. 163
JATT,PBIAS Command ..................................................................................................................................................... 164
JATT,PTAU Command ...................................................................................................................................................... 165
JATT,ROLL Command ...................................................................................................................................................... 166
JATT,SEARCH Command ................................................................................................................................................. 167
JATT,SPDTAU Command ................................................................................................................................................. 168
JATT,SUMMARY Command .............................................................................................................................................. 169
JATT,TILTAID Command .................................................................................................................................................. 171
JATT,TILTCAL Command ................................................................................................................................................. 172
JBAUD Command.............................................................................................................................................................. 173
JBIN Command.................................................................................................................................................................. 175
JBOOT ................................................................................................................................................................................ 178
JBOOT Command.............................................................................................................................................................. 178
JBOOT,LBAND Command ................................................................................................................................................ 179
JCONN Command ............................................................................................................................................................. 180
JDIFF .................................................................................................................................................................................. 181
JDIFF Command ................................................................................................................................................................ 181
JDIFF,AVAILABLE Command ........................................................................................................................................... 183
JDIFFX,EXCLUDE Command ............................................................................................................................................ 184
JDIFFX,GNSSOUT Command ........................................................................................................................................... 185
JDIFFX,INCLUDE Command ............................................................................................................................................. 187
JDIFFX,SOURCE Command.............................................................................................................................................. 189
JDIFFX,TYPE Command ................................................................................................................................................... 190
JEPHOUT,PERIODSEC Command ................................................................................................................................... 192
JETHERNET ....................................................................................................................................................................... 193
JETHERNET Command Overview .................................................................................................................................... 193
JETHERNET,MODE ........................................................................................................................................................... 194
JETHERNET,PORTI ........................................................................................................................................................... 195
JFLASH .............................................................................................................................................................................. 196
JFLASH Command Overview ........................................................................................................................................... 196
JFLASH,DIR Command ..................................................................................................................................................... 197
JFLASH,FILE,CLOSE Command ...................................................................................................................................... 198
JFLASH,FILE,NAME Command ........................................................................................................................................ 199
JFLASH,FILE,OPEN Command ........................................................................................................................................ 201
JFLASH,FREESPACE Command...................................................................................................................................... 202
JFLASH,NOTIFY,CONNECT Command ............................................................................................................................ 203
JFLASH,QUERYCONNECT Command ............................................................................................................................. 204
JFREQ Command .............................................................................................................................................................. 205
JATLAS,LIMIT Command .................................................................................................................................................. 206
JFORCEAPP Command .................................................................................................................................................... 209
JGEO Command ................................................................................................................................................................ 209
JI Command ....................................................................................................................................................................... 211
JK Command ..................................................................................................................................................................... 212
JLBEAM Command ........................................................................................................................................................... 216
JLIMIT Command .............................................................................................................................................................. 218
JLXBEAM Command ......................................................................................................................................................... 219
JMASK Command ............................................................................................................................................................. 221
JMODE ............................................................................................................................................................................... 222
JMODE Overview ............................................................................................................................................................... 222
JMODE Command ............................................................................................................................................................. 223
JMODE,BASE Command .................................................................................................................................................. 224
JMODE,BDSOFF Command .............................................................................................................................................. 225
JMODE,FIXLOC Command ............................................................................................................................................... 226
JMODE,FOREST Command .............................................................................................................................................. 227
JMODE,GLOFIX ................................................................................................................................................................. 228
JMODE,GLOOFF Command.............................................................................................................................................. 229
JMODE,GPSOFF Command .............................................................................................................................................. 230
JMODE,GPSONLY Command ........................................................................................................................................... 231
JMODE,L1ONLY Command .............................................................................................................................................. 232
JMODE,MIXED Command ................................................................................................................................................. 233
JMODE,NULLNMEA Command ........................................................................................................................................ 234
JMODE,SBASNORTK Command ...................................................................................................................................... 236
JMODE,SBASR Command ................................................................................................................................................ 237
JMODE,STRICTRTK Command ........................................................................................................................................ 238
JMODE,SURETRACK Command ...................................................................................................................................... 239
JMODE,SURVEY Command .............................................................................................................................................. 240
JMODE,TIMEKEEP Command .......................................................................................................................................... 241
JMODE,TUNNEL Command .............................................................................................................................................. 242
JMSG99 Command ............................................................................................................................................................ 243
JNMEA ............................................................................................................................................................................... 244
JNMEA,GGAALLGNSS Command.................................................................................................................................... 244
JNMEA,PRECISION Command ......................................................................................................................................... 245
JNP Command ................................................................................................................................................................... 246
JOFF ................................................................................................................................................................................... 247
JOFF Command................................................................................................................................................................. 247
JOFF,ALL Command ......................................................................................................................................................... 248
JPOS Command ................................................................................................................................................................ 249
JPRN,EXCLUDE Command............................................................................................................................................... 254
JQUERY ............................................................................................................................................................................. 257
JQUERY,GUIDE Command ............................................................................................................................................... 257
JQUERY,RTKPROG Command......................................................................................................................................... 256
JQUERY,RTKSTAT Command .......................................................................................................................................... 258
JQUERY,TEMPERATURE Command ............................................................................................................................... 261
JRAD Command Overview ............................................................................................................................................... 262
JRAD,1 Command ............................................................................................................................................................. 263
JRAD,1,LAT,LON,HEIGHT Command ............................................................................................................................... 264
JRAD,1,P Command .......................................................................................................................................................... 265
JRAD,2 Command ............................................................................................................................................................. 266
JRAD,3 Command ............................................................................................................................................................. 267
JRAD,7 Command ............................................................................................................................................................. 268
JRAD,9 Command ............................................................................................................................................................. 269
JRAD,10 Command ........................................................................................................................................................... 270
JRTCM3,ANTNAME Command ......................................................................................................................................... 277
JRTCM3,EXCLUDE ............................................................................................................................................................ 278
JRTCM3,INCLUDE Command ........................................................................................................................................... 279
JRTCM3,NULLANT Command .......................................................................................................................................... 280
JRTK................................................................................................................................................................................... 281
JRTK Command Overview ................................................................................................................................................ 281
JRTK,1 Command.............................................................................................................................................................. 282
JRTK,1,LAT,LON,HEIGHT Command ............................................................................................................................... 283
JRTK,1,P Command .......................................................................................................................................................... 284
JRTK,5 Command.............................................................................................................................................................. 285
JRTK,5,Transmit Command .............................................................................................................................................. 286
JRTK,6 Command.............................................................................................................................................................. 287
JRTK,12 Command............................................................................................................................................................ 288
JRTK,17 Command............................................................................................................................................................ 289
JRTK,18 Command............................................................................................................................................................ 290
JRTK,18,BEARING Command .......................................................................................................................................... 291
JRTK,18,NEU Command ................................................................................................................................................... 292
JRTK,28 Command............................................................................................................................................................ 293
JSHOW Command ............................................................................................................................................................. 295
JSHOW,ASC Command .................................................................................................................................................... 297
JSHOW,BIN Command ...................................................................................................................................................... 300
JSHOW,CONF Command .................................................................................................................................................. 301
JSHOW,GP Command ....................................................................................................................................................... 303
JSHOW,THISPORT Command .......................................................................................................................................... 304
JSIGNAL Command .......................................................................................................................................................... 305
JTAU Command Overview ................................................................................................................................................ 311
JTAU,COG Command ....................................................................................................................................................... 312
JTAU,SPEED Command.................................................................................................................................................... 314
PCSI,1 Command (Status Line A, Channel 0 command)................................................................................................. 319
PCSI,1,1 Command (Beacon Status command) .............................................................................................................. 321
PCSI,2 Command (Status Line B, Channel 1 command)................................................................................................. 323
PCSI,3,1 Command (Receiver Search Dump command) ................................................................................................ 325
PCSI,3,2 Command (Ten Closest Stations command) .................................................................................................... 328
PCSI,3,3 Command (Station Database command) .......................................................................................................... 330
PCSI,5 Command (Set Baud Rates command) ................................................................................................................ 333
PCSI,6 Command (Reboot command).............................................................................................................................. 334
PCSI,7 Command (Swap Modes command) .................................................................................................................... 335
Bin1 Message .................................................................................................................................................................... 366
Bin2 Message .................................................................................................................................................................... 369
Bin3 Message .................................................................................................................................................................... 371
Bin5 Message .................................................................................................................................................................... 376
Bin16 Message .................................................................................................................................................................. 380
Bin19 Message .................................................................................................................................................................. 386
Bin35 Message .................................................................................................................................................................. 391
Bin36 Message .................................................................................................................................................................. 394
Bin44 Message .................................................................................................................................................................. 396
Bin45 Message .................................................................................................................................................................. 400
Bin62 Message .................................................................................................................................................................. 402
Bin65 Message .................................................................................................................................................................. 404
Bin66 Message .................................................................................................................................................................. 402
Bin69 Message .................................................................................................................................................................. 404
Bin76 Message .................................................................................................................................................................. 406
Bin80 Message .................................................................................................................................................................. 411
Bin89 Message .................................................................................................................................................................. 413
Bin93 Message .................................................................................................................................................................. 415
Bin122 Message ................................................................................................................................................................ 431
Introduction
The purpose of the GNSS Technical Reference Manual is to serve as a resource for software engineers and system
integrators engaged in the configuration of GNSS receivers. It may also be of use to persons with knowledge of the
installation and operation of GNSS navigation systems.
This reference covers features, commands, logs, and operating modes for a variety of Hemisphere GNSS products: not
all aspects described apply to all products.
Information is provided as follows:
•
Quick Start provides basic information to get you started using your Hemisphere GNSS receiver
•
•
•
GNSS Technology and Platforms provides information on the GNSS engine, GNSS solutions, and GNSS platforms
Receiver Operation introduces general operational features of the receiver, receiver operation modes, and default
operation parameters
Commands and Messages are grouped by their type (General, GNSS, e-Dif, Data, RAIM, etc.) and for each type
the commands or messages are initially listed in a table with a brief description. Each command and message is
then described in detail in separate topics.
•
•
Resources provides resources for additional information
Change History provides a list of all topics updated in a release and a short description of each change
•
Troubleshooting provides troubleshooting advice
Copyright Notice
Hemisphere GNSS Applications
Copyright © Hemisphere GNSS (2018). All rights reserved.
No part of this manual may be reproduced, transmitted, transcribed, stored in a retrieval system or translated into
any language or computer language, in any form or by any means, electronic, mechanical, magnetic, optical,
chemical, manual or otherwise, without the prior written permission of Hemisphere GNSS.
Topic Last Updated: v1.08 June 21, 2017
GNSS Technical Reference Manual
Current Version: v1.09 January 8, 2018
Page 1
Quick Start
This topic provides basic information to get you started using your Hemisphere GNSS receiver.
•
What is my receiver type? Send the JT command.
•
How do I load firmware onto my receiver and why would I do this?
Use RightARM. Loading firmware allows you to run application specific capabilities.
•
What is my current receiver configuration? Send the JSHOW query.
For Vector products send the JATT,SUMMARY query.
•
What commands are supported by my receiver?
Find out what GNSS engine is in your receiver (issue JT command) then go to the Overview topic for
commands supported by that GNSS engine.
•
How do I send a command to my receiver?
Connect receiver to a PC and use a terminal program (such as HyperTerminal) or Hemisphere GNSS'
PocketMax or SLXMon. For more information refer to the User Guide for your product.
•
How do I turn on data messages (such as GPGGA) for a receiver? See Configuring the Data Message Output.
Topic Last Updated: v1.07 / February 16, 2017
GNSS Technical Reference Manual
Current Version: v1.09 January 8, 2018
Page 2
GNSS Technology and Platforms
GNSS Engine
GNSS Engine Overview
The GNSS engine is always operating regardless of the DGNSS mode of operation. The following sections describe
the general operation of the receiver.
•
Satellite Tracking
•
Positioning Accuracy
•
Update Rates
Both the GNSS and SBAS operation of the receiver module features automatic operational algorithms. When powered
for the first time, the receiver system performs a "cold start," which involves acquiring the available GNSS satellites in
view and the SBAS differential service. To do this, the receiver needs a compatible GNSS antenna connected that offers
a relatively clear, unobstructed view of the sky. While you can often achieve this indoors with an antenna placed against
a window, you may need to place the antenna outside, for example on a roof or a short distance away from the building.
If SBAS is not available in a particular area, an external source of RTCM SC-104 differential correction may be used. If
an external source of correction data is needed, the external source needs to support an eight data bit, no parity and
one stop bit configuration (8-N-1). See also SBAS Overview.
Topic Last Updated: v1.07 / February 16, 2017
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Current Version: v1.09 January 8, 2018
Page 3
GNSS Technology and Platforms
Satellite Tracking
The receiver automatically searches for GNSS satellites, acquires the signal, and manages the associated navigation
information required for positioning and tracking. This is a hands-free mode of operation. Satellite acquisition quality is
described as a signal-to-noise ratio (SNR) and the higher the SNR, the better the signal reception quality. SNR
information is provided by the receiver through the use of NMEA 0183 data messages available via its multiple serial
ports.
Topic Last Updated: v1.07 / February 16, 2017
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Current Version: v1.09 January 8, 2018
Page 4
GNSS Technology and Platforms
Positioning Accuracy
The receiver is a sub-meter product with 95% horizontal accuracy under ideal conditions.
To determine the positioning performance of the receiver, Hemisphere GNSS gathers a 24-hour data set of positions in
order to log the diurnal environmental effects and full GPS constellation changes. Data sets shorter than 24 hours tend to
provide more optimistic results.
The horizontal performance specification of 95% accuracy is, as stated above, based on ideal conditions. In reality,
obstruction of satellites, multipath signals from reflective objects, and operating with poor corrections will detract from the
receiver’s ability to provide accurate and reliable positions. Differential performance can also be compromised if the
receiver module is used in a region without sufficient ionospheric coverage.
Further, if external corrections are used, the baseline separation between the remote base station antennas can affect
performance.
Since the receiver will be used in the real world, blockage of the line of sight to SBAS satellites is often inevitable. The
COAST function provides solace from obstruction of any differential correction source (SBAS, Beacon, RTCM, Atlas,
RTK, e-Dif) for 30 to 40 minutes depending on the amount of tolerable performance drift. In fact, our receivers will
COAST when differential correction is lost no matter what the differential source is: SBAS, Beacon, RTCM, Atlas,
RTK, or e-Dif.
The estimated positioning precision is accessible through the use of NMEA 0183 command responses as described
Commands and Messages.
Because the receiver cannot determine accuracy with respect to a known location in real time (so is traditionally
performed in post-mission analyses), the precision numbers are relative in nature and are only approximates.
Topic Last Updated: v1.06 / March 10, 2015
GNSS Technical Reference Manual
Current Version: v1.09 January 8, 2018
Page 5
GNSS Technology and Platforms
Update Rates
The update rate of each NMEA 0183 and binary message of the receiver can be set independently with a maximum that
is dependant upon the message type. For example, some messages have a 1 Hz maximum while other messages have
a 20 Hz maximum. The higher update rates, such as 20 Hz, are an option and can be obtained at an additional cost.
Higher update rates are valuable for applications where:
•
•
•
•
•
Higher speeds are present such as in aviation
You have manual navigational tasks such as in agricultural guidance
You have an automated or autonomous navigational task such as in robotics or machine control Keep the following
in mind regarding message rates:
Some messages can only be OFF or ON (0 or 1Hz) Example: $JASC,RTCM3,1
Some messages can only be 0 or 1 Hz, but will come out once first, then only if they change Example:
$JASC,BIN95,1
•
•
Messages that are available at other rates can be set to rates SLOWER than 1 Hz (see Note 1 below)
Example: $JASC,GPGGA,0.1
•
•
If the receiver is subscribed to 10 or 20Hz, the receiver can log at rates FASTER than 1 Hz (see Note 2 below)
Example: $JASC,GPGGA,5
Note 1: Slower than 1 Hz.
Use the following guidelines:
To log once
every
seconds
Use
JASC,xxxx,
2
3
0.5
0.3333
4
0.25
5
.2
6
0.1667
7
0.1429
8
0.125
9
0.1111
10
0.1
15
0.0667
20
0.05
25
0.04
40
0.025
50
0.02
100
0.01
120
0.0083
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GNSS Technology and Platforms
Rates not listed above may be possible but may not log on integer seconds. Users should test to see if the results are
acceptable for their application.
Note 2: Faster than 1Hz, if subscribed.
Acceptable rates are 1, 2, 4, 5, 10 or 20 Hz. Using rates other than those listed will result in data appearing in a rate
similar to the rate requested, but the data times will be quantized to 0.05 second resolution. This is due to the receiver’s
internal computing rate of 20 Hz. Time resolution is 0.05 seconds even if the receiver is only subscribed for 10 Hz data.
Quantizing may result in a slightly different number of messages per minute than expected. For example, 3 Hz data
produces approximately 172 messages per minute due to quantizing, instead of the expected 180 messages.
Using rates other than a factor of 20 Hz may result in quantized data. Regardless, the data in the message is referenced
to the time of the message. For example, 3 Hz data may appear at a time of 0.30 seconds; the data is referenced to 0.3
seconds, not 0.333333 seconds.
Topic Last Updated: v1.00 / August 11, 2010
GNSS Technical Reference Manual
Current Version: v1.09 January 8, 2018
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GNSS Technology and Platforms
DGNSS Solutions
COAST Technology
Crescent and Eclipse OEM boards feature Hemisphere GNSS’ exclusive COAST technology that enables Hemisphere
GNSS Crescent and Eclipse receivers to utilize old DGPS correction data for 40 minutes or more without significantly
affecting positioning quality.
Note: Crescent refers to Crescent, Crescent Vector
When using COAST, these receivers are less likely to be affected by differential signal outages due to signal blockages,
weak signals, or interference.
Note: To obtain a full set of SBAS corrections, the COAST technology provides the following benefits:
•
•
•
•
Accurate and minimal position drift during temporary loss of differential signal corrections
Sub-meter accuracy up to 40 minutes after differential signal loss
Outstanding performance in environments where maintaining a consistent differential link is difficult
It is standard with Crescent and Eclipse GPS receiver technology
Topic Last Updated: v1.06 / March 10, 2015
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Current Version: v1.09 January 8, 2018
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GNSS Technology and Platforms
SBAS
SBAS Overview
The following topics describe the general operation and performance monitoring of the Space-Based Augmentation
System (SBAS) demodulator within the receiver module:
•
Automatic tracking
•
Performance
•
WAAS
•
WAAS DGPS
•
WAAS Signal Information
•
WAAS Reception
•
WAAS Coverage
Topic Last Updated: v1.00 / August 11, 2010
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Current Version: v1.09 January 8, 2018
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SBAS Automatic Tracking
The SBAS demodulator featured within the receiver automatically scans and tracks multiple SBAS satellite signals, as
specified by the JWAASPRN command (defaulted to WAAS PRN 135 and 138, suitable for use in North America).
If the default satellites become disabled, the receiver automatically tracks different satellites. This automatic tracking
enables you to focus on other aspects of your application rather than ensuring the receiver is tracking SBAS correctly.
The SBAS demodulator features two-channel tracking that enhances the ability to maintain acquisition on an SBAS signal
satellite in regions where more than one satellite is in view.
This redundant tracking approach results in more consistent signal acquisition in areas where signal blockage of either
satellite is possible.
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GNSS Technology and Platforms
SBAS Performance
SBAS performance is described in terms of bit error rate (BER). The SBAS receiver requires a line of sight to the SBAS
satellite to acquire a signal.
The BER number indicates the number of unsuccessfully decoded symbols in a moving window of 2048 symbols. Due
to the use of forward error correction algorithms, one symbol is composed of two bits. The BER value for both SBAS
receiver channels is available in the RD1 message.
A lower BER indicates data is being successfully decoded with fewer errors, providing more consistent throughput. The
BER has a default no-lock of 500 or more. As the receiver begins to successfully acquire a signal, a lower BER results.
For best operation, this value should be less than 150 and ideally less than 20.
SBAS broadcasts an ionospheric map on a periodic basis and it can take up to five minutes to receive the map on
startup. Until it downloads the SBAS map the receiver uses the broadcast ionosphere model, which can result in a lower
performance compared to when the map has been downloaded. This is the case for any GNSS product supporting SBAS
services.
WARNING: When the map has been downloaded, you may observe a position jump due to the potentialdifference between
the GPS ionospheric model and the ionosphere SBAS map. To minimize the impact of this issue on the use of the receive
wait up to five minutes before using the receiver or issue the JQUERY,GUIDE command to 'ask' the receiver if it feels the
performance will be sufficient for operation.
Topic Last Updated: v11.07 / February 16, 2017
WAAS
The US Federal Aviation Administration developed the Wide Area Augmentation System (WAAS) to provide accurate
positioning to the aviation industry. In addition to providing a high quality and accurate service for this industry, the
service is available free of charge to civilians and markets in North America.
Other government agencies have developed similar WAAS-compatible systems for their respective geographic regions.
•
•
•
Europe - the European Space Agency, the European Commission and EUROCONTROL jointly developed the European
Geostationary Navigation Overlay Service (EGNOS)
Japan - the MTSAT Satellite-based Augmentation System (MSAS) was developed by the Japan Civil Aviation Bureau (JCAB)
India - the Airport Authority of India and the Indian Space Research Organization (ISRO) are deploying the GPS Aided Geo
Augmented Navigation system (GAGAN)
These compatible augmentation systems fall into a broader category often referred to as Space Based Augmentation
System (SBAS). The receiver is capable of receiving correction data from all WAAS- compatible SBAS.
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GNSS Technology and Platforms
WAAS DGPS
WAAS differential, and other compatible SBAS, use a state-based approach in their software architecture. These services
take in reference data from a network of base stations and endeavor to model the sources of error directly, rather than
computing the sum impact of errors upon observed ranges. The advantage of this approach is that the error source can be
more specifically accounted for during the correction process.
Specifically, WAAS calculates separate errors for the following:
•
•
•
Ionospheric error
GPS satellite timing errors
GPS satellite orbit errors
Provided that a GNSS satellite is available to the WAAS reference station network for tracking purposes, orbit and timing
error corrections will be available for that satellite. Ionospheric corrections for that satellite are only available if the signal
passes through the ionospheric map provided by WAAS, which covers most of North America.
To improve the ionospheric map provided by WAAS, the receiver extrapolates information from the broadcast ionospheric
coverage map, extending its effective coverage. This allows the receiver to be used successfully in regions that
competitive products may not. This is especially important in Canada for regions north of approximately 54° N latitude and
for outer regions of the Caribbean.
The process of estimating ionospheric corrections beyond the WAAS broadcast map is not as good as having an
extended WAAS map and accuracy degradation may occur.
The map links below depict the broadcast WAAS ionospheric map coverage and the Hemisphere GNSS extrapolated
version, respectively. As the two maps show, the Hemisphere GNSS extrapolated version’s coverage is greater in all
directions, enhancing usable coverage.
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•
Broadcast WAAS ionospheric correction map
•
Extrapolated WAAS ionospheric correction map
Topic Last Updated: v1.07 / February 16, 2017
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GNSS Technology and Platforms
WAAS Signal Information
WAAS and other SBAS systems transmit correction data on the same frequency as GPS, allowing the use of the same
receiver equipment used for GPS. Another advantage of having WAAS transmit on the same frequency as GPS is that
only one antenna element is required.
Topic Last Updated: v1.00 / August 11, 2010
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WAAS Reception
Since WAAS broadcasts on the same frequency as GPS, the signal requires a line of site in the same manner as
GPS to maintain signal acquisition.
Because of their locations, SBAS satellites may appear lower on the horizon than GPS satellites—it depends on the
geographic position on land. When using WAAS correction data, the receiver can provide the azimuth and elevation of
all satellites to aid in determining their position with respect to the antenna.
Topic Last Updated: v1.00 / August 11, 2010
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GNSS Technology and Platforms
WAAS Coverage
The figure below depicts the current WAAS coverage provided by the geostationary satellites.
The WAAS satellites are identified by their pseudorange number (PRN). In some areas, two or more satellites
may be visible.
Note: Signal coverage may be present in some areas without either sufficient ionospheric map coverage or
satellites with valid orbit and clock corrections. In such cases performance may be degraded compared to
areas fully covered by the WAAS ionospheric coverage.
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EGNOS
The European Geostationary Navigation Overlay Service (EGNOS) uses multiple geostationary satellites and a
network of ground stations to transmit differential correction data for public use. EGNOS is currently located over the
Atlantic Ocean and Africa.
Because of their location over the equator, these satellites may appear lower over the horizon as compared to GPS
satellites - it depends on the geographic position on the land. In regions where the satellites appear lower on the
horizon, they may be more susceptible to being masked by terrain, foliage, buildings or other objects, resulting in signal
loss. Increased distance from the equator and the satellite's longitude cause the satellite to appear lower on the horizon.
Hemisphere GNSS's COAST technology helps alleviate this problem by maintaining system performance when EGNOS
signal loss occurs for extended periods of time. More information on COAST technology is provided later in this chapter.
The figure below shows approximate EGNOS coverage provided by the satellites. Virtually all of Europe, part of
Northern Africa, and part of the Middle East is covered with at least one signal. Most of Europe is covered by three
signals.
Note: Increased distance from the equator and the satellite’s longitude cause the
satellite to appear lower on the horizon. Although a good amount of signal coverage
is shown in northern latitudes for EGNOS, it may not be usable because of its low
elevation angle and the potential for it to be obstructed. Testing of the system in the
area of its use is recommended to ensure that the signal is sufficiently available.
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MSAS
The MTSAT Satellite-based Augmentation System (MSAS) is currently run by the Japan Meteorological Agency (JMA).
MSAS provides GPS augmentation information to aircraft through MTSAT (Multi-functional Transport Satellite) located
approximately 36000 km above the equator (geostationary earth orbit).
MSAS generates GPS augmentation information by analyzing signals from GPS satellites received by monitor
stations on the ground. This augmentation information consists of GPS-like ranging signal and correction information
on GPS errors caused by the satellites themselves or by the ionosphere.
The MSAS signal provides accurate, stable, and reliable GPS position solutions to aircraft, resulting in a considerable
improvement in the safety and reliability of GPS positioning. This enables aviation users who are under very strict safety
regulations to use GPS positioning as a primary navigation system.
Visit http://www.jma.go.jp/jma/jma-eng/satellite/ for more information on MSAS and MTSAT.
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GAGAN
The GPS Aided Geo Augmented Navigation system (GAGAN) is currently under deployment by the Indian government
and is anticipated to be operational by 2011. It operates similarly to the other SBAS regions described previously and will
broadcast on one geostationary satellite (PRN 127) over the Western portion of the Indian Ocean. GAGAN should be
visible in India at elevation angles in excess of 50º above the horizon. This will provide an excellent correction source in
virtually all areas of the subcontinent.
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Radiobeacon
Radiobeacon Overview
Many marine authorities, such as Coast Guards, have installed networks of radiobeacons that broadcast DGPS
corrections to their users. With increasing use of these networks for terrestrial applications, there is increasing
densification of these networks inland.
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Radiobeacon Range
The broadcasting range of a 300 kHz beacon depends on a number of factors, including:
•
•
•
•
•
•
Transmission power
Free space loss
Ionospheric state
Surface conductivity
Ambient noise
Atmospheric losses
Signal strength decreases with distance from the transmitting station, mostly due to spreading loss. This loss is a result of
the signal’s power being distributed over an increasing surface area as the signal radiates away from the transmitting
antenna.
The expected broadcast range also depends on the conductivity of the surface over which it travels. A signal will
propagate further over a surface area with high conductivity than over a surface with low conductivity.
Lower conductivity surfaces, such as dry, infertile soil, absorb the power of the transmission more than higher
conductivity surfaces, such as sea water or arable land.
A radio beacon transmission has three components:
1.
Direct line-of-sight wave
The line-of-sight wave is insignificant beyond visual range of the transmitting tower and does not have a
substantial impact upon signal reception.
2.
Ground wave
The ground wave portion of the signal propagates along the surface of the earth, losing strength due to
spreading loss, atmospheric refraction and diffraction, and attenuation by the surface over which it travels
(dependent upon conductivity).
3.
Sky wave
Depending on its reflectance, this skyward portion of the beacon signal may bounce off the ionosphere and
back to Earth, causing reception of the ground wave to fade. Fading—which may cause reception to fade in
and out—occurs when the ground and sky waves interfere with each other. This problem usually occurs in the
evening when the ionosphere becomes more reflective and usually on the edge of coverage areas. Fading is
not usually an issue with overlapping coverage areas of beacons and their large overall range.
Atmospheric attenuation plays a minor part in signal transmission range because it absorbs and scatters the signal. This
type of loss is the least significant of those described.
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Radiobeacon Reception
Various noise sources affect beacon reception and include:
•
•
•
•
•
Engine noise
Alternator noise
Noise from power lines
DC to AC inverting equipment
Electric devices such as CRTs, electric motors, and solenoids
Noise generated by these types of equipment can mask the beacon signal, reducing or impairing reception.
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Radiobeacon Antenna Location
When using the internal beacon receiver as the correction source, antenna location will influence the performance of the
internal beacon receiver.
A good location will:
•
•
•
•
Have a clear view of the sky (important for GNSS, WAAS, and Atlas signal reception)
Be at least three feet away from all forms of transmitting antennas, communications, and electrical equipment, to
reduce the amount of noise present at the antenna
Be the best for the application, such as the center line of the vehicle or vessel (the position calculated by the
beacon receiver is measured to the center of the antenna)
Not be in areas that exceed specified environmental conditions
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Radiobeacon Coverage
The figure below shows the approximate radiobeacon coverage throughout the world. Light shaded regions denote current
coverage, with beacon stations shown as white circles. The world beacon networks continue to expand. For more current
coverage, visit the Hemisphere GNSS web site at www.hemispheregnss.com.
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Atlas
Atlas Overview
Atlas services provides correction data to subscribers of the system with the use of a geostationary transponder.
The Atlas service is based on a network of reference stations, located around the world, that communicate GNSS raw
observation data to control centers. At the control centers the GNSS correction data is decoded, processed, and
packaged into a proprietary format for transmission to a geostationary Atlas communications satellite. The satellite
broadcasts the correction information back to earth over a large signal footprint. The signal can be demodulated by any
Atlas enabled receivers.
The Atlas service does not provide RTCM SC-104 formatted data, instead using a proprietary, highly compressed,
correction format. With this service, the positioning accuracy does not degrade as a function of distance to a particular
base station because the data content is not composed of a single base station’s information; it is composed of an entire
network’s information.
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Atlas Signal Information
The Atlas signal is a line-of-sight UHF signal that is similar to GNSS. For the Atlas differential receiver to acquire the
signal, there must be a line of sight between the antenna and the geostationary communications satellite.
Various Atlas communications satellites are used for transmitting the correction data to Atlas users around the world.
When the Atlas receiver has acquired an Atlas signal, the elevation and azimuth are available in the menu system to
enable troubleshooting line-of sight problems.
Contact your Atlas service provider for further information on this service.
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Atlas Reception
Atlas services broadcast at a similar frequency to GNSS and as a result is a line-of-sight system; there must be a line of
sight between the antenna and the Atlas satellite for reception of the service.
Atlas services use geostationary satellites for communication. The elevation angle to these satellites is dependent upon
latitude. For latitudes higher than approximately 55° North or South, the Atlas signal may be blocked more easily by
obstructions such as trees, buildings, and terrain.
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Atlas Automatic Tracking
The Hemisphere GNSS Atlas receiver features an automatic mode that allows it to locate the best spot beam if more
than one is available in a particular region. With this function you do not need to adjust the receiver’s frequency. The
receiver also features a manual tune mode for flexibility.
See the JFREQ command for more information on automatic and manual tuning.
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Atlas Receiver Performance
Atlas receivers provide both a lock indicator and a BER (bit error rate) to describe the lock status and reception quality.
Both these features depend on a line of sight between the antenna and the geostationary communications satellite
broadcasting the Atlas correction information.
Atlas capable Hemisphere GNSS antennas are designed with sufficient gain at low elevation angles to perform well at
higher latitudes where the signal power is lower and the satellite appears lower on the horizon. The BER number
indicates the number of unsuccessfully decoded symbols in a moving window of 2048 symbols. Because of the use of
forward error correction algorithms, one symbol is composed of two bits.
The BER has a default, no-lock value of 500. As the receiver begins to successfully acquire the signal a lower BER
results. For best operation this value should be less than 150 and ideally less than 20.
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Crescent Base Station
Crescent Base Station Overview
The Crescent receiver with e-Dif subscription can operate in a DGPS base station mode. NMEA 0183 commands need
to be sent to the receiver to enter this mode. These commands may be automatically issued through customized
software or through a simple terminal interface running on a PC, PDA, or data logger. DGPS Base Station Commands
provides detailed information on the commands supported by the base station application.
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Crescent Base Station Startup
When the receiver running the e-Dif application first starts up, it requires a few minutes to gather enough satellite tracking
information to model the errors for the future. Once commands are sent to put the receiver into base station mode,
corrections will be generated and can be sent via the serial port to rover receivers. In some more challenging GNSS
environments, the time required to model errors can take up to 10 minutes. The receiver must be stationary during this
process and the antenna for the base station must be secured in a stable location.
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Crescent Base Station Calibration
Base station calibration is the process of modeling the errors at the base station. Calibration can be performed in either a
relative or an absolute sense, depending on positioning needs. Relative positioning provides positions that are accurate to
one another but there may be some offset from the true geographical position.
Calibrating for relative positioning is easier than for absolute position since you are not restricted to using a point with
known coordinates. Calibrating for absolute positioning mode requires placing the GPS antenna at a known reference
location. Care should be taken to use a location that has good sky visibility and is relatively free from obstructions.
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Crescent Base Station Performance
Base station performance depends primarily on the site location for the base station GNSS antenna. An ideal location
would have no obstructions above the height of the antenna, offering a full 180º by 360º view of the sky. In reality,
obstructions such as trees, vehicles, people, and buildings nearby both block satellite signals and reflect interfering
signals called multipath signals. Multipath degrades the accuracy of the satellite measurements and detracts from the
receiver’s ability to provide accurate and reliable corrections for the rovers.
For a rover to work optimally, a base station should be near by the rover’s area of operation. As distance from the
base to the rover increases, the modeling process cannot tune the solution to the exact environmental conditions at
the rover’s location and the rover’s accuracy will not be as good. Best performance is attained when the distance
from your base to your rover is less than 50 km (30 miles).
Generally, there is little to no advantage to using a base station if it is more than 300 km (180 miles) from the rover.
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e-Dif
e-Dif - Extended Differential Option for the Crescent Receiver
The Crescent receiver module is designed to work with Hemisphere GNSS’ patented Extended Differential (e-Dif)
software. e-Dif is an optional mode where the receiver can perform with differential-like accuracy for extended periods of
time without the use of a differential service. It models the effects of ionosphere, troposphere, and timing errors for
extended periods by computing its own set of pseudo-corrections.
e-Dif may be used anywhere geographically and is especially useful where SBAS networks have not yet been installed,
such as South America, Africa, Australia, and Asia. Two things are required to enable e-Dif. First your receiver will
require the e-Dif application software to be installed on it. As well, a software key, called a subscription code, is needed
for the receiver to use e-Dif. Both can be installed in the field using a PC computer. See Using RightARM to Load
Firmware if you need to install the application firmware onto your receiver. To install a subscription code, contact
Hemisphere GNSS for a JK command which can be issued to your receiver.
Positioning with e-Dif is jump-free compared to a receiver working with just raw GPS provided the receiver consistently
maintains a lock on at least four satellites at one time. The accuracy of positioning will have a slow drift that limits use of
the e-Dif for approximately 30 to 40 minutes although it depends on how tolerant the application is to drift as e-Dif can be
used for longer periods.
This mode of operation should be tested to determine if it is suitable for the application and for how long the user is
comfortable with its use. As accuracy will slowly drift, the point at which to recalibrate e-Dif to maintain a certain level of
accuracy must be determined.
The figure below displays the static positioning error of e-Dif while it is allowed to age for fourteen consecutive cycles of
30 minutes. The top line indicates the age of the differential corrections. The receiver computes a new set of corrections
using e-Dif during the calibration at the beginning of each hour and modifies these corrections according to its models.
After the initialization, the age correspondingly increases from zero until the next calibration.
The position excursion from the true position (the lines centered on the zero axis are northing [dark line] and easting [light
line]) with increasing correction age is smooth from position to position; however, there is a slow drift to the position. The
amount of drift depends on the rate of change of the environmental errors relative to the models used inside the e-Dif
software engine.
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Note: You decide how long e-Dif is to function before between calibrations and you should test this operation
mode to determine an acceptable level of performance.
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e-Dif Rover Mode Operation
Rover mode operation of the Crescent receiver unit with the optional e-Dif application requires NMEA 0183 commands.
These commands may be automatically issued through customized software or through a simple terminal interface
running on a PC, PDA or data logger. See e-Dif Commands for detailed information on the commands supported by the eDif feature.
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e-Dif Startup
On startup, the receiver with the e-Dif application software running requires a few minutes to gather enough satellite
tracking information to model the errors for the future. And in some environments this can take up to 10 minutes. The
receiver does not have to be stationary for this process but it must be tracking the satellites throughout it. This process of
gathering information and the subsequent initialization of e-Dif is referred to as "calibration."
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e-Dif Rover Calibration
Rover calibration is the process of modeling the errors at the rover. Calibration can be performed in either a relative or
an absolute sense, depending on positioning needs. Relative positioning provides positions that are accurate to one
another but there may be some offset from the true geographical position. Additionally, unless the same point is used for
all calibrations and its assumed position stored, it is possible for different cycles of e-Dif to have an offset.
Calibrating for relative positioning is easier than for absolute position, since you are not restricted to using a point with
known coordinates. Calibrating for absolute positioning mode requires placing the GPS antenna at a known reference
location. Use this point for subsequent calibrations.
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e-Dif Rover Performance
The Crescent receiver’s positioning performance is dependant upon the rate at which the environmental modeling of eDif and the environmental errors diverge. The more that e-Dif is able to model the errors correctly, the longer it will
provide reliable and accurate positioning. As there is no way in real time to know the rate of divergence, a rule of thumb
is to set the maximum age of differential to either 30 or 40 minutes, depending on how much error the application is able
to tolerate (or simply recalibrate before 30 to 40 minutes goes by). Hemisphere GNSS testing has shown that relative
accuracy will often be better than 1.0 m 95% of the time after 30 minutes of e-Dif operation.
You should perform testing at your location to determine the level of performance that would be seen on average. When
testing this feature, it is a good idea to look at a number of e-Dif cycles per day, and monitor performance against a
known coordinate and possibly other receivers in autonomous and differential mode. You should do this over a number
of days with different states of the ionosphere.
You can monitor the energy level of the ionosphere based upon the amount of solar flare activityat
http://www.spaceweather.com.
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L-Dif
L-Dif Local Differential Option
Local differential (L-Dif) is a specialized message type that can be sent only between two Crescent-based receivers.
One receiver is used as the base station and must remain stationary. It is extremely useful to know the coordinates of
the base station position but averaging the position over several days will also suffice. The second receiver is used as
a rover and the messages must be sent either through a cable or over a radio link.
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L-Dif Startup
On startup, the receiver with the L-Dif running requires several commands to initialize the proprietary messages
that are sent over the air.
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L-D if Performance
The receiver’s positioning performance in L-Dif mode is dependant upon:
•
•
•
Environment of the base and rover receivers
Distance between them and
Accuracy of the entered coordinates of the base station
Hemisphere GNSS suggests you perform your own testing at your location to determine the level of performance you
would expect on average. When testing this feature, conduct tests of 12-24 hours—in different environments—and
monitor performance against a known coordinate. Do this over a number of days with different states of the ionosphere.
You can monitor the energy level of the ionosphere based upon the amount of solar flare activity at
http://www.spaceweather.com.
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RTK Overview
Real Time Kinematic (RTK) positioning is the highest form of navigational accuracy for GNSS receivers. Hemisphere
GNSS offers RTK for both Crescent and Eclipse platforms. See RTK commands for more information.
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Multi-Funcation Application (MFA) Software
Your device may include MFA software that allows you to set the positioning (mode) hierarchy of your device. To verify if
your device contains MFA software send the $JAPP command to the device; the response indicates whether you have
MFA as follows:
•
•
Without MFA (two specific applications listed) Example: $>JAPP,WAASRTKB,AUTODIFF,1,2
With MFA (MFA and one specific application listed) Example: $>JAPP,MFA,SBASRTKB,1,2
The hierarchy is the path your device follows to determine what differential source to use depending on available
sources. The hierarchy is as follows:
1.
RTK
2.
L-band (Atlas)
3.
SBAS
4.
Beacon
5.
External RTCM
6.
Autonomous
If you are running RTK and you lose your RTK radio link, the device defaults to the next highest mode, being either Atlas
high precision service or SBAS (if available). If the new signal becomes unusable, the next mode will be selected (for
example Beacon or External RTCM). Finally, if no correction signals are available, the device defaults to Autonomous.
You can include or exclude specific sources. For example, you can exclude sources that you do not want your device to
use, such as if you want to use only beacon. If you do not exclude the other sources your device may use SBAS instead.
Another example is if you want to exclude Atlas (when you do not have an Atlas subscription) to conserve power. You
include and exclude sources using
the $JDIFFX,INCLUDE and $JDIFFX,EXCLUDE commands, respectively.
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Post-Processing
Crescent and Eclipse receiver modules can output raw measurement data for post processing applications. The raw
measurement and ephemeris data are contained in the following messages, which must be logged in a binary file:
Observations: Bin 76 (GPS), Bin 66 (GLONASS), Bin 36 (BEIDOU)
Or
Bin 16 (All constellations; required for GALILEO)
Ephemeris: Bin 95 (GPS), Bin 65 (GLONASS), Bin 35 (BEIDOU), Bin 45 (GALILEO)
Time conversion: Bin 94 (GPS), Bin 34 (BEIDOU), Bin 44 (GALILEO)
(Crescent receivers must log Bin 94, 95, and 96 messages for GPS). Depending on the application, the binary data can
be logged to a file and then translated to RINEX at a later time on a PC.
Hemisphere GNSS provides a RINEX translator. It is available by contacting technical support at Hemisphere GNSS;
however, because there is limited ability to store station information in the binary file, developers may consider writing
their own translator. Some code is available for developers but with very limited support. The code should be self-evident
to developers familiar with RINEX and knowledgeable in C language.
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Hemisphere GNSS Hardware Platforms
Hardware Platforms Overview
Hemisphere GNSS offers the following hardware platforms:
•
•
•
Crescent
Crescent Vector II
Eclipse II
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Universal Development Kit
The Universal Development Kit allows you to integrate a Hemisphere GNSS OEM board into your design and includes the
following:
•
•
•
•
•
Enclosure
Main carrier board
Set of three adapter boards for use with small form factor Hemisphere GNSS OEM boards
Power cable and AC power supply
Two serial cables - one straight serial cable and one null modem cable for RTK
•
The Universal Development Kit supports the following Hemisphere GNSS OEM boards:
•
Enclosure
•
Crescent
•
Crescent Vector II
•
Eclipse II
•
miniEclipse
•
LX-2 (L-band DGPS and high precision services)
Depending on the Hemisphere GNSS OEM board you purchase with your Universal Development Kit, an Integrator’s Guide is
available for download from the Hemisphere GNSS website at www.hemispheregnss.com (search for Universal Development
Kit).
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Evaluating Receiver Performance
Hemisphere GNSS evaluates performance of the receiver with the objective of determining best-case performance in a
real-world environment. Our testing has shown that the receiver achieves a performance better than 0.6 m 95% of the
time in typical DGPS modes.
The qualifier of 95% is a statistical probability. Manufacturers often use a probability of RMS, one sigma, or one
standard deviation. These three terms all mean the same thing and represent approximately 67% probability.
Performance measures with these probabilities are not directly comparable to a 95% measure since they are lower
probability (less than 70% probability).
Table 1 summarizes the common horizontal statistical probabilities.
Table 1: Horizontal Accuracy Probability Statistics
Accuracy Measure
Probability (%)
rms (root mean square)
63 to 68
CEP (circular error probability)
50
R95 (95% radius)
95 to 98
2drms (twice the distance root)
95
It is possible to convert from one statistic to another using Table 2. Using the value where the 'From' row meets the 'To'
column, multiply the accuracy by this conversion value.
Table 2: Accuracy Conversions
To
From
CEP
rms
R95
2drms
CEP
1
1.2
2.1
2.4
rms
0.83
1
1.7
2.0
R95
0.48
.59
1
1.2
2drms
0.42
.5
.83
1
For example, Product A, after testing, has an accuracy of 90 cm 95% of the time (R95). To compare
this to Product B that has a sub-meter horizontal rms specification of 60 cm:
1.
Select the value from where the 'R95' row and the 'rms' column intersect (to convert to rms). This conversion
value is 0.59.
2.
Multiply the 90 cm accuracy by this conversion factor and the result is 53 cm rms. Compared to Product B’s
60 cm specification of sub-meter rms, Product A offers better performance.
To properly evaluate one receiver against another statistically, the receivers should be using identical correction input
(from an external source) and share the same antenna using a power splitter (equipped with appropriate DC-blocking of
the receivers and a bias-T to externally power the antenna). With this setup, the errors in the system are identical with the
exception of receiver noise.
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Although this is a comparison of the GNSS performance qualities of a receiver, it excludes other performance merits of a
GNSS engine. The dynamic ability of a receiver should always be compared in a similar way with the test subjects sharing
the same antenna. Unless a receiver is moving, its software filters are not stressed in a similar manner to the final product
application. When testing dynamically, a much more accurate reference would need to be used, such as an RTK system,
so that a "truth" position per epoch is available.
Further, there are other performance merits of a GNSS engine such as its ability to maintain a lock on GNSS and SBAS
satellites. When evaluating this ability, the same GNSS antenna should be shared between the receivers test subjects.
For the sake of comparing the tracking availability of one receiver to another, no accurate "truth" system is required unless
performance testing is also to be analyzed. Again, an RTK system would be required; however, it is questionable how its
performance will fare with environments where there are numerous obstructions such as foliage. Other methods of
providing a truth reference may need to be provided through observation times on surveyed monuments or traversing
well-known routes.
Should you look to compare two RTK systems, determining truth can be very complicated. A rigorous dynamic comparison
of two competing RTK systems should only be attempted by individuals and organizations familiar with RTK and potentially
with inertial navigation equipment. Fortunately, most manufacturer's RTK performance is specified in similar accuracy
values, and in general, RTK accuracy is quite similar across different manufacturers.
Note: Contact Hemisphere GNSS Technical Support for further assistance in developing a test setup or
procedure for evaluation of the receiver.
Topic Last Updated: v1.07 / February 16, 2017
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Current Version: v1.09/January 8, 2018
Page 48
Receiver Operation
Receiver Operation Overview
When turned on, the receiver goes through an internal startup sequence. It is, however, ready to communicate immediately.
Refer to the receiver-specific manual for the power specifications of the product.
When its antenna has an unobstructed view of the sky, the receiver provides a position in approximately 60 seconds and
acquires SBAS lock in about 30 seconds more.
Note: The receiver can take up to 5 minutes to receive a full SBAS ionospheric map. Optimum accuracy is
obtained when the receiver is processing corrected positions using complete ionosphere information.
Topic Last Updated: v1.00 / August 11, 2010
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Current Version: v1.09/January 8, 2018
Page 49
Communicating with the Receiver
Communicating with Receivers
The receiver module features three primary serial ports (A, B, C) that may be configured independently of each other.
The ports can be configured to output a combination of data types:
•
•
•
NMEA 0183
Hemisphere GPS proprietary binary format
RTCM SC-104
The usual data output is NMEA 0183 messages because these are the industry standard.
Note: If different data types are required to be output from the receiver simultaneously, such as NMEA 0183 and
binary or NMEA 0183 and RTCM SC-104, ensure that the software used for logging and processing of the data
has been designed to correctly parse the different data types from the single stream of data.
Topic Last Updated: v1.00 / August 11, 2010
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Current Version: v1.09/January 8, 2018
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Receiver Operation
NMEA 0183 Messages
NMEA 0183 is a communications standard established by the National Marine Electronics Association (NMEA). NMEA
0183 provides data definitions for a variety of navigation instruments and related equipment such as gyrocompasses,
Loran receivers, echo sounders, and GNSS receivers.
NMEA 0183 functionality is virtually standard on all GNSS equipment available. NMEA 0183 has an ASCII character
format that enables the user to read the data via a receiving device with terminal software.
The following is an example of one second of NMEA 0183 data from the receiver:
$GPGGA,144049.0,5100.1325,N,11402.2729,W,1,07,1.0,1027.4,M,0,M,,010
*61
$GPVTG,308.88,T,308.88,M,0,0.04,N,0.08,K*42
$GPGSV,3,1,10,02,73,087,54,04,00,172,39,07,66,202,54,08,23,147,48,*7 9
$GPGSV,3,2,10,09,23,308,54,11,26,055,54,15,00,017,45,21,02,353,45*78
$GPGSV,3,3,10,26,29,257,51,27,10,147,45,45,,,,,,,,*74
The NMEA 0183 standard allows manufacturers to define proprietary custom commands and to combine data into
proprietary custom messages. Proprietary NMEA 0813 messages are likely to be supported only by specific manufacturers.
All messages and ports can be configured independently (see example below).
Port
Baud
Rate
Messages
A
9600
GPGGA, one every 1
second
GPGSV, one every 5
seconds
B
19200
GPGGA, one every 2
seconds
Bin1, one every 1 second
Bin2, one every 1 second
A selection of NMEA 0183 data messages can be configured at various update rates with each message having a
maximum update rate. A different selection of NMEA 0183 messages with different rates can be configured on another port.
Commands and Messages Overview presents information about the NMEA 0183 interface of the receiver smart antenna.
See Reference Documents for contact information if you need to purchase a copy of the NMEA 0183 standard.
Topic Last Updated: v1.07 / February 16, 2017
Hemisphere GNSS Proprietary Binary Interface
Hemisphere GNSS proprietary binary messages may be output from the receiver simultaneously with NMEA 0183
messages.
Binary messages are inherently more efficient than NMEA 0183 and would be used when maximum
communication efficiency is required. Some receiver-specific pieces of information are only available through
binary messages, such as raw data for post processing.
Note: If you need to log binary data, make sure the logging software has opened the file as a binary file;
otherwise, data may be lost.
Topic Last Updated: v1.06 / March 10, 2015
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Receiver Operation
RTCM SC-104 Protocol
RTCM SC-104 is a standard that defines the data structure for differential correction information for a variety of
differential correction applications. It was developed by the Radio Technical Commission for Maritime services (RTCM)
and has become an industry standard for communication of correction information. RTCM is a binary data protocol and is
not readable with a terminal program. Because it is a binary format and not ASCII text, it appears as "garbage" data on
screen.
The following is an example of how the RTCM data appears on screen:
mRMP@PJfeUtNsmMFM{nVtIOTDbA^xGh~kDH`_FdW_yqLRryrDuh
cB\@}N`ozbSD@O^}nrGqkeTlpLLrYpDqAsrLRrQN{zW|uW@H`z]~aG
xWYt@I`_FxW_qqLRryrDCikA\@Cj]DE]|E@w_mlroMNjkKOsmMFM{ WDw
W@HVEbA^xGhLJQH`_F`W_aNsmMFM[WVLA\@S}amz@ilIuP
qx~IZhTCpLLrYpdP@kOsmMFM[kVDHwVGbA^P{WWuNt_SW_yMs
mMnqdrhcC\@sE^ZfC@}vJmNGAHJVhTCqLRryrdviStW@H_GbA^ P{wxu[k
All Hemisphere GNSS receivers support RTCM v2.x Type 1, Type 5, Type 6, and Type 9 messages for DGPS
positioning.
Hemisphere GNSS receivers do not support RTCM v2.x messages for RTK positioning. However RTCM v3.x
messages (Type 1001 through 1008) are suitable for RTK positioning.
Note: RTCM v2.x is a local area data standard. This means that performance degrades as a function
of distance from the base station when:
Positioning with external connection input to the receiver from an external source or
Outputting corrections from the receiver to another GNSS receiver.
The additional degradation depends on the difference in observed orbit and ionospheric errors
between the reference station and the remote unit. A general rule of thumb is an additional 1 m error
per 100 miles.
This error is often seen as a bias in positioning, resulting in a position offset. The scatter of the receiver
is likely to remain close to constant.
See Reference Documents for RTCM contact information to purchase a copy of the RTCM SC-104 specifications.
Topic Last Updated: v1.07 / February 16, 2017
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Receiver Operation
Firmware and Subscriptions
Firmware
About Firmware
Hemisphere GNSS products are built on one of three receiver platforms, each of which has specific firmware applications
available.
•
•
•
Crescent - WAAS, e-Dif, Atlas service, L-Dif/RTK base, L-Dif/RTK rover
Crescent Vector - WAAS, RTK rover
Eclipse - WAAS/RTK base, RTK roverAtlas high precisionservices
Some products may require purchasing a subscription code to unlock specific functionality. See Subscription Codes for
more information.
As its name suggests, firmware is somewhere between hardware and software. Like software, it is a computer program
which is executed by a microprocessor or a microcontroller. But it is also tightly linked to a piece of hardware, and has
little meaning outside of it.
Within the context of GNSS, the hardware is the GNSS receiver and it is the receiver’s processor that executes the
firmware. The receiver’s processor supports two simultaneous versions of firmware but only one version operates at a
given time. The two versions—referred to as applications—may have different functionality.
Use the JAPP command to change between two receiver applications.
Topic last updated: v1.07/ February 16, 2017
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Receiver Operation
Using RightARM to Load Firmware
RightARM is Hemisphere GNSS software that allows you to load the various GNSS receiver firmware options and
updates as they are provided by Hemisphere GNSS.
To load the firmware:
1.
Download the latest version of RightARM from http://www.hemispheregnss.com.
2.
Install RightARM application on your computer.
3.
Connect the receiver to your computer and power on the receiver.
4.
Double-click the RightARM icon
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to launch the program. The following screen appears.
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Receiver Operation
1.
Click the Open Receiver button
or select Receiver > Connect. The Open Receiver
window appears, so you can identify a connected receiver.
2.
Select the Comm Port on your computer to which the receiver is connected, select the 19200 baud rate for the
receiver, and then click OK.
Note: You must set the baud rate to 19200.
When RightARM has successfully connected to the receiver the following message appears in the
lower left corner of the screen.
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Receiver Operation
3.
Click the Programming View button . The Programming View window appears, enabling you to select different
firmware programming options.
4.
Select the Program Type you want to install and then click Select File. The Open window
appears.
Note: Most Hemisphere GNSS receivers have two application locations available for firmware. In this
case, select the Application option under Program Type and follow the remaining steps. Once the
process is complete, you will repeat the process, selecting the Application 2 option when you reach
this step again.
5.
6.
Select the required firmware file from the location where you saved it on your computer and click
Open. "File Loaded" appears in the status window on the Programming View window.
7.
Click the Erase and Program button to erase the firmware that is currently installed on the receiver in the selected
application location and install the newly selected file in its place. "Erasing...Please Wait" appears in the Status field
and a progress bar below this message indicates the programming progress. Once the new firmware has been
successfully loaded on the receiver "Programming Done" appears in the Status field.
Note: Before pressing the Erase and Program button, the Activate Loader check box in the Programming
View window will be selected. After pressing the Erase and Program button, the check box should be
cleared and the Status field should show that the receiver is in loader mode and ready to receive the new
firmware file. If the Activate Loader check box remains selected, turn the receiver off and then back on
again, close and restart RightARM, and then start over at step 5.
WARNING: Do not to interrupt the power supply to the receiver, and do not interrupt the communication
link between the PC and the receiver until programming is complete. Failure to do so may cause the
receiver to become inoperable and will require it to be returned to the factory for repair.
8.
Once the appropriate firmware has been loaded, click the Close button to close the Programming View window.
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Receiver Operation
Note: If a second application needs to be loaded, turn off the receiver, repeating all the steps starting at
step 4, and on step 8 select the Application 2 option from the Program Type field.
9.
Exit RightARM, turn off your receiver, and then disconnect the receiver from your computer.
Topic Last Updated: v1.07/ February 16, 2017
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Current Version: v1.09/January 8, 2018
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Receiver Operation
Subscriptions Codes
This section covers:
•
•
•
Finding the serial number and inputting a subscription code (e-Dif, RTK, 20 Hz or 10Hz, etc.) into a Hemisphere GNSS
receiver
Viewing the status and interpreting the $JI subscription date codes
The difference between the receiver’s response to the $JK and $JI commands
Topic Last Updated: v1.07/ February 16, 2017
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Receiver Operation
Subscribing to an Application
Activating an application code on a Hemisphere GNSS receiver requires the following:
•
•
•
•
Serial communication cable to connect the Hemisphere GNSS receiver to the serial COM port on the computer
Download SLXMon from the www.hemispheregnss.com and install it on your PC or use a generic terminal program
such as HyperTerminal
Load the application to which to subscribe onto the Hemisphere GNSS receiver (see Using RightARM to Load
Firmware)
Purchase the application subscription code from Hemisphere GNSS or an authorized Hemisphere GNSS
representative
To activate the application on a Hemisphere GNSS receiver:
1.
Connect the Hemisphere GNSS receiver to the serial COM port on the computer.
Start SLXMon.
2.
Select File > Connect and then select the appropriate Comm Port and Baud Rate to open communication with the
receiver.
3.
Select Control > View Command Page.
4.
In the Receiver Command Page window type $JAPP in the Message box and then click Send.
5.
Confirm which applications are loaded onto the receiver and the order in which they appear in the Reply box.
Example Response (in Reply box):
$>JAPP,WAAS,DIFF
where WAAS (SBAS, EGNOS, MSAS) is the number one application (or application number 1) and DIFF (same as e-Dif) is the
"other" application (or application number 2)
6.
If DIFF is listed as application number 2 in the $JAPP response then type the following command in the Message box:
$JAPP,O
7.
where 'O' is the "other" application in the example. This swaps the two applications so that DIFF is be the current
application.
8.
Type the following command in the Message box:
$JI
The first number in the response is the serial number of the receiver. Example
Response (in Reply box):
$>JI,810133,1,3,09031998,01/06/1998,12/31/2018,3.5,31
The serial number is 810133. You will need to provide it to Hemisphere GNSS with your request for an e-Dif
subscription code.
1.
Type the following command in the Message box after receiving the subscription code from Hemisphere GNSS:
$JK,nnnn
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Receiver Operation
where 'nnnn' is the subscription number. The receiver will respond with "subscription accepted."
Topic Last Updated: v1.7 / February 16, 2017
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Receiver Operation
Interpreting the $JK 'Date'/Subscription Codes
Subscriptions codes enable GNSS differential correction sources on your receiver. When discussing them it is important
to understand the following.
•
•
•
The YYYY component of a MM/DD/YYYY formatted date—returned by the JK command—is not always just the
year component of that date. When a date’s year starts with 30, only the 30 represents the year - and that year is
3000. A subscription expiration date of 01/01/3000 effectively means there is no expiration date.
The last two digits of the 30YY 'date' represent the data output rate and the GNSS differential correction sources
that have been subscribed to and are therefore enabled on your receiver. Hemisphere GNSS refers to these two
digits as the Additive Code (see Understanding Additive Codes).
The 30 and the 00 in the 'year' 3000, then, represents "Expires 3000 (so effectively does not expire), the data rate
is 10 Hz, and SBAS is enabled." The 'year' 3015 indicates "Expires 3000, the data rate is 20 Hz and differential
correction sources SBAS/e-Dif/RTK and L-Dif have been subscribed to and are enabled."
Below is an example of the $JK command response, part of which is the subscription start and expiration dates (the
Date Code is shaded).
$>JK,01/01/3000,0
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Receiver Operation
Understanding Additive Codes
Tables 1 and 2 below provide subscription information for Crescent and Eclipse receivers, where the data rate and
subscription are indicated by the 'date' returned by the JK command. For Eclipse II receivers, refer to Eclipse II
Subscription Codes. The part of the date that indicates the data rate and subscription code is called the Additive
Code. The last two digits in the subscription expiration date’s ‘year’ comprise the Additive Codes, that is, the
available data output rate from the receiver, plus the subscriptions—the enabled GPS differential correction sources.
Table 3 outlines the components of the Crescent, Eclipse, and Eclipse II Additive Codes. The subscription codes
have different additive components for Crescent, Eclipse, and Eclipse II.
Table 1: Crescent Subscription Codes
Date Code (Additive
Code)
Hex Code
Maximum
Data Rate
Subscription Description
3000 (0)
HEX 0
10 Hz
SBAS enabled
3001 (1)
HEX 1
20 Hz
SBAS enabled
3002 (0+2)
HEX 2
10 Hz
SBAS, e-Dif enabled
3003 (1+2)
HEX 3
20 Hz
SBAS, e-Dif enabled
3004 (0+4)
HEX 4
10 Hz
SBAS, RTK Rover enabled
3005 (1+4)
HEX 5
20 Hz
SBAS, RTK Rover enabled
3006 (0+2+4)
HEX 6
10 Hz
SBAS, RTK Rover, e-Dif enabled
3007 (1+2+4)
HEX 7
20 Hz
SBAS, RTK Rover, e-Dif enabled
3008 (0+8)
HEX 8
10 Hz
SBAS, L-Dif Rover, L-Dif Base, RTK Base enabled
3009 (1+8)
HEX 9
20 Hz
SBAS, L-Dif Rover, L-Dif Base, RTK Base enabled
3010 (0+2+8)
HEX A
10 Hz
3011 (1+2+8)
HEX B
20 Hz
SBAS, L-Dif Rover, L-Dif Base, RTK Base, e-Dif
enabled
SBAS, L-Dif Rover, L-Dif Base, RTK Base, e-Dif
enabled
3012 (0+4+8)
HEX C
10 Hz
SBAS, L-Dif Rover, L-Dif Base, RTK Rover, RTK
Base enabled
3013 (1+4+8)
HEX D
20 Hz
SBAS, L-Dif Rover, L-Dif Base, RTK Rover, RTK
Base enabled
3014 (0+2+4+8)
HEX E
10 Hz
SBAS, L-Dif Rover, L-Dif Base, RTK Rover, RTK
Base, e-Dif enabled
3015 (1+2+4+8)
HEX F
20 Hz
SBAS, L-Dif Rover, L-Dif Base, RTK Rover, RTK
Base, e-Dif enabled
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Receiver Operation
Table 2: Eclipse Subscription Codes
Date Code
(Additive
Code)
Hex Code
Maximum
Data Rate
Subscription Description
3000 (0)
HEX 0
10 Hz
SBAS, Atlas enabled
3001 (1)
HEX 1
20 Hz
SBAS,Atlas enabled
3004 (0+4)
HEX 4
10 Hz
SBAS,Atlas , RTK Rover, RTK Base, Raw L1/L2 data enabled
3005 (1+4)
HEX 5
20 Hz
SBAS,Atlas , RTK Rover, RTK Base, Raw L1/L2 data enabled
3008 (0+8)
HEX 8
10 Hz
SBAS,Atlas , RTK Base, Raw L1/L2 data enabled
3009 (1+8)
HEX 9
20 Hz
SBAS,Atlas , RTK Base, Raw L1/L2 data enabled
3016 (0+16)
HEX 10
10 Hz
SBAS,Atlas , Raw L1/L2 data enabled
3017 (1+16)
HEX 11
20 Hz
SBAS,Atlas , Raw L1/L2 data enabled
Eclipse II Subscription Codes (go here)
Table 3: Crescent, Eclipse, and Eclipse II Additive Codes Components
Crescent
Code
Description
Eclipse
Code
Description
Eclipse II
Code
Description
0
10 Hz
0
10 Hz
0
10 Hz
1
20 Hz
1
20 Hz
1
20 Hz
2
e-Dif
2
n/a
2
e-Dif
4
L-Dif Rover, L-Dif Base, RTK
Rover
4
Raw L1/L2 Data, RTK Base, RTK
Rover
4
RTK Rover
(minimum
L1 only)
8
RTK Base
8
Raw L1/L2 Data, RTK Base
8
RTK Base
(minimum
L1 only)
16
n/a
16
Raw L1/L2 Data
16
Raw Data
(minimum
L1 only)
32
n/a
32
n/a
32
L2 signals
64
n/a
64
n/a
64
GLONASS signals
(minimum L1 only)
Crescent Additive Code Examples
•
•
10 Hz (SBAS), e-Dif, and RTK is 0+2+4 = 6 (so 3006)
20 Hz (SBAS), e-Dif, and RTK is 1+2+4 = 7 (so 3007)
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Receiver Operation
Comparing the JI and JK Responses
Example 1:
In the following Crescent examples, the Date Code is shaded.
•
JI query date code example:
$>JI,311077,1,7,04102005,01/01/1900,01/01/3000,6.8Hx,46
•
JK query date code example:
$>JK,01/01/3000,0,(1, 2, 5 or no number)
In the JK example the last two digits ('00') of the Date Code ('3000') represent the Hex Code (the second column of Table 2 above).
The last digit to the right (1, 2, 5 or no number) is the Downgrade Code...this is the output rate in Hertz indicating a downgrade from the
default of 10 Hz. So if 1, 2 or 5 does not appear (no number), the output rate is the default 10 Hz.
The Date Codes are identical in either query and are directly related to each other. Also, the last digit in the JK query is the hexadecimal
equivalent of the last two digits in the Date Code. The following example further illustrate this (Date Code is shaded).
Note: The JI response provides the decimal Date Code while the JK response provides both the decimal Date Code and the hex
Date Code (the Hex Code).
Example 2:
$>JI,311077,1,7,04102005,01/01/1900,01/01/3015,6.8Hx,46
•
JK query date code example:
$>JK,01/01/3015,F
In this example the last two digits ('15') of the Date Code ('3015') is the decimal equivalent of the last value ('F'), which is the Hex Code (see
the last row in Table 1 above). Example shows no downgrade code.
Topic Last Updated: v1.03 / January 11, 2012
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Receiver Operation
Eclipse II Subscription Codes
Use the information below to determine your Eclipse II subscription code and its features.
1
2
4
8
16
0x01
0x02
0x04
0x08
20H z
e-Dif
RTK Rover,
RTK Base,
Raw Out
RTK Base,
0x40
Raw Out
L2
GLONASS
0
3001
1
Y
3002
2
Y
3003
3
Y
3004
4
Y
3005
5
Y
Y
3006
6
Y
Y
3007
7
Y
3008
8
Y
3009
9
Y
Y
3010
A
Y
Y
3011
B
Y
Y
3012
C
Y
Y
3013
D
Y
Y
Y
3014
E
Y
Y
Y
3015
F
Y
3016
10
Y
3017
11
Y
3018
12
Y
Y
Y
0x20
3000
Y
Y
0x10
Hex
Code
Y
Y
64
Date Code
(Additive Code)
Raw Out
Standard
Y
32
Y
Y
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Receiver Operation
Y
Y
3019
13
Y
Y
3020
14
Y
Y
3021
15
Y
Y
Y
3022
16
Y
Y
Y
3023
17
Y
Y
3024
18
Y
Y
3025
19
Y
Y
Y
3026
1A
Y
Y
Y
3027
1B
Y
Y
Y
3028
1C
Y
Y
Y
3029
1D
Y
Y
Y
Y
3030
1E
Y
Y
Y
Y
3031
1F
Y
3032
20
Y
3033
21
Y
Y
3034
22
Y
Y
3035
23
Y
Y
3036
24
Y
Y
3037
25
Y
Y
Y
3038
26
Y
Y
Y
3039
27
Y
Y
3040
28
Y
Y
3041
29
Y
Y
Y
3042
2A
Y
Y
Y
3043
2B
Y
Y
3044
2C
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
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Receiver Operation
Y
Y
Y
Y
Y
Y
Y
3046
2E
Y
Y
Y
Y
3047
2F
Y
Y
3048
30
Y
Y
3049
31
Y
Y
Y
3050
32
Y
Y
Y
3051
33
Y
Y
Y
3052
34
Y
Y
Y
3053
35
Y
Y
Y
Y
3054
36
Y
Y
Y
Y
3055
37
Y
Y
Y
3056
38
Y
Y
Y
3057
39
Y
Y
Y
Y
3058
3A
Y
Y
Y
Y
3059
3B
Y
Y
Y
Y
3060
3C
Y
Y
Y
Y
3061
3D
Y
Y
Y
Y
Y
3062
3E
Y
Y
Y
Y
Y
3063
3F
Y
3064
40
Y
3065
41
Y
Y
3066
42
Y
Y
3067
43
Y
Y
3068
44
Y
Y
3069
45
Y
Y
3070
46
Y
Y
Y
Y
Y
Y
Y
Y
2D
Y
Y
Y
3045
Y
Y
Y
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Receiver Operation
Y
3071
47
Y
Y
3072
48
Y
Y
3073
49
Y
Y
Y
3074
4A
Y
Y
Y
3075
4B
Y
Y
Y
3076
4C
Y
Y
Y
3077
4D
Y
Y
Y
Y
3078
4E
Y
Y
Y
Y
3079
4F
Y
Y
3080
50
Y
Y
3081
51
Y
Y
Y
3082
52
Y
Y
Y
3083
53
Y
Y
Y
3084
54
Y
Y
Y
3085
55
Y
Y
Y
Y
3086
56
Y
Y
Y
Y
3087
57
Y
Y
Y
3088
58
Y
Y
Y
3089
59
Y
Y
Y
Y
3090
5A
Y
Y
Y
Y
3091
5B
Y
Y
Y
Y
3092
5C
Y
Y
Y
Y
3093
5D
Y
Y
Y
Y
Y
3094
5E
Y
Y
Y
Y
Y
3095
5F
Y
3096
60
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
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Receiver Operation
Y
Y
3097
61
Y
Y
Y
3098
62
Y
Y
Y
3099
63
Y
Y
Y
3100
64
Y
Y
Y
3101
65
Y
Y
Y
Y
3102
66
Y
Y
Y
Y
3103
67
Y
Y
Y
3104
68
Y
Y
Y
3105
69
Y
Y
Y
Y
3106
6A
Y
Y
Y
Y
3107
6B
Y
Y
Y
Y
3108
6C
Y
Y
Y
Y
3109
6D
Y
Y
Y
Y
Y
3110
6E
Y
Y
Y
Y
Y
3111
6F
Y
Y
Y
3112
70
Y
Y
Y
3113
71
Y
Y
Y
Y
3114
72
Y
Y
Y
Y
3115
73
Y
Y
Y
Y
3116
74
Y
Y
Y
Y
3117
75
Y
Y
Y
Y
Y
3118
76
Y
Y
Y
Y
Y
3119
77
Y
Y
Y
Y
3120
78
Y
Y
Y
Y
3121
79
Y
Y
Y
Y
3122
7A
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
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Receiver Operation
75
Y
Y
Y
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Current Version: v1.09/January 8, 2018
Y
Y
Y
Y
3123
7B
Y
Y
Y
Y
3124
7C
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Receiver Operation
Y
Y
Y
Y
Y
3125
7D
Y
Y
Y
Y
Y
Y
3126
7E
Y
Y
Y
Y
Y
Y
3127
7F
Y
Y
Topic Last Updated: v1.03 / January 11, 2012
GNSS Technical Reference Manual
Current Version: v1.09/January 8, 2018
Page 71
Receiver Operation
Determining the Receiver Type and Current Application
To determine the current receiver type, use the JT command. Table 1 shows the receiver type indicated by the JT
response.
Table 1: $JT Response and Receiver Type
$JT Response
Receiver Type
SX1x
SX-1
SX2x
Crescent
SLXx
SLX2/SLX3
DF2x
Eclipse
DF3x
Eclipse II
MF3x
miniEclipse
The 'x' in the responses represents the receiver’s current application. For example, if x = i, as in SX2i, 'i' is the
application code for e-Dif.
Table 2 shows the application for the application code in the JT response.
Table 2: $JT Response and Application
$JT Responses with
Application Code
Receiver Application
r
RTK rover
b
RTK base
i
e-Dif
g
L-band
g
WAAS
g
Standalone
a
Vector
Topic Last Updated: v1.02 / January 25, 2011
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Current Version: v1.09/January 8, 2018
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Receiver Operation
Configuring the Receiver
You can configure all aspects of receiver operation through any serial port using NMEA 0183 commands. You can:
•
•
•
•
•
Select one of the two on-board applications:
o Two applications may be loaded at the same time, but only one can be active
o You can select the active application through serial commands or through menu options on products with
displays
Set the baud rate of communication ports
Select NMEA 0183 data messages to output on the serial ports and select the output rate of each message
Set the maximum differential age cut-off
Set the satellite elevation angle cut-off mask
The appropriate commands are described in Commands and Messages.
Topic Last Updated: v1.07 / February 16, 2017
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Current Version: v1.09/January 8, 2018
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Receiver Operation
Configuring the Data Message Output
In addition to its differential-only Port D, the receiver features three primary bidirectional ports referred to as A, B, and C.
You can configure GPS data messages for all three ports by sending NMEA 0183 commands to the receiver module
through all its communication ports. You can configure the output of Port B through A, for instance, and vice versa. The
JASC NMEA message allows you to turn the messages on or off as required.
Note: For receivers that have a USB port that supports writing to a USB flash drive you can specify Port T as a
port to receive messages.
In the examples below where you can specify the port, use 'PORTT' to specify Port T.
'THIS' Port and the 'OTHER' Port
The NMEA 0183 interface for Port A and B both use 'THIS' and 'OTHER' terminology.
•
•
THIS port
The port you are currently connected to for inputting commands. To get the data output through THIS port it is
not necessary to specify 'this' (see Example 1 below).
The OTHER port
To specify the OTHER port for the data output, you need to include 'OTHER' in the command. See the two
examples following which are both based on you being connected to Port B.
Example 1:
To turn the GPGGA message on at 5 Hz on Port B, use the following command:
$JASC,GPGGA,5
Because B is THIS it does not have to be specified.
Example 2:
To turn the GPGGA message on at an output rate of 5 Hz on Port A, use the following command:
$JASC,GPGGA,5,OTHER
Because B is THIS and A is OTHER, you have to specify OTHER. In contrast, when turning messages on or off on Port C
from Port A or Port B, you must specify Port C in the command.
Example 3:
To turn the GPGLL NMEA 0183 message on at 10 Hz on Port C, use the following command:
$JASC,GPGLL,10,PORTC
As with Port A and B, when communicating directly with Port C, you do not need to specify anything at the end of the
message. See Commands and Messages for more information.
Topic Last Updated: v1.02 / January 25, 2011
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Current Version: v1.09/January 8, 2018
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Receiver Operation
Saving the Receiver Configuration
Each time the configuration of the receiver is changed, the new configuration should be saved so the receiver
does not have to be reconsidered for the next power cycle.
To save the settings:
•
Issue the JSAVE command. The receiver records the current configuration to non-volatile memory. The
receiver indicates when the save process, which takes about five seconds, is complete.
Topic Last Updated: v1.00 / August 11, 2010
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Current Version: v1.09/January 8, 2018
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Receiver Operation
Using Port D for RTCM Input
The receiver has a port designed to accommodate externally supplied corrections input according to the RTCM SC-104
protocol. Port D provides this functionality although it has been fixed to operate at a baud rate of 9600 (8 data bits, no
parity, and 1 stop bit, that is, 8-N-1).
To use Port D of the receiver for correction input, you must set the receiver to operate in beacon differential mode using
the following command:
$JDIFF,BEACON
This command was designed to “turn on” Port D differential operation in our products because many use the Hemisphere
GNSS SBX beacon module interfaced to Port D.
Note: The receiver is compatible with RTCM SC-104 message types 1-3, 5-7, 9 and 16 although not all the
message types contain differential data.
To return to using SBAS as the correction source, send the following command to the receiver:
$JDIFF,WAAS
See Commands and Messages for detailed information on NMEA 0183 messages supported by the receiver.
Topic Last Updated: v1.06 / March 10, 2015
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Current Version: v1.09/January 8, 2018
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Receiver Operation
SBX-4 Database Mode
Enabling Database Mode
Database mode is automatically enabled when the SBX-4 receives a valid RMC message on Port 0. This requires the
baud rate of Port 0 to be the same as the corresponding GPS receiver port.
Performance in Database Mode
In most installations Database mode will result in faster initial acquisition and better GPS accuracy compared
to Auto mode.
In some installations Database mode may not work as well as Auto mode for the following reasons:
•
•
The closest station is not in the station database and the SBX-4 has not yet received a Type7 Almanac message.
Most stations now broadcast the Almanac message every ten minutes. Assuming the SBX-4 can tune to a
surrounding station and receive a Type7 message, it will update the station database and automatically retune to the
closest station.
Signal quality in the area is poor. IEC61108-4 requires the receiver to switch away from a station when WER rises
above 10%. For installations that do not need to comply with IEC61108-4 this threshold can be increased as usable
corrections can be obtained for word error rates up to 50%.
Available Production Configuration Settings
Disable the automatic switch to Database mode:
$PCSI,8,NITRAM,A
Enable weak signal tracking (WER of 50%):
$PCSI,8,NITRAM,W
Enable legacy Q value output (in place of WER):
$PCSI,8,NITRAM,Q
Set SBX-4 to factory defaults:
$PCSI,8,NITRAM,E
Topic Last Updated: v1.00 / August 11, 2010
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Current Version: v1.09/January 8, 2018
Page 77
Receiver Operation
Ethernet Configuration
As of firmware version V5.6.1, the Hemisphere P328 receiver board has Ethernet support. It is disabled by default, but may
be enabled.
The P328 is connected to a carrier board or enclosure which connects the P328’s Ethernet pins to a standard RJ-45 jack
(with integrated magnetics as appropriate).
Enabling and Disabling Ethernet
The full current state of Ethernet configuration may be checked with the command “$JETHERNET”. Doing this when Ethernet
is disabled should give a result like the following:
$JETHERNET
$>JETHERNET,MAC,8C-B7-F7-F0-00-01
$>JETHERNET,MODE,OFF
$>JETHERNET,PORTI,OFF
$> Current Ethernet IP Address: None
To enable Ethernet, determine if the receiver is allowed to be assigned an IP address automatically via DHCP, or statically
assigned. If you are unsure, please contact the administrator of the network you wish to connect it to.
To enable Ethernet support with a DHCP-assigned IP address, simply use the command:
$JETHERNET,MODE,DHCP
The receiver will attempt to get an address from the DHCP server on the network. You should be able to see the current IP
address reported by a “$JETHERNET” query change.
To enable Ethernet support with a statically assigned IP address, use the command
$JETHERNET,MODE,STATIC,ip,subnet,gateway,dns
where ip/subnet/gateway/dns are each replaced with the relevant IP address. The gateway and dns parameters are
optional, and only useful for allowing outgoing connections from the P328, which are not currently supported anyway. An
example command would be
$JETHERNET,MODE,STATIC,192.168.0.42,255.255.255.0
If one wishes to disable Ethernet use the command
$JETHERNET,MODE,OFF
With Ethernet enabled, one can access the receiver on Windows machnies via “HGNSSxx”, where “xx” is the receiver’s
ESN. For example from the command line one could use the command,
ping HGNSS1234567
Enabling Ethernet Services
With Ethernet enabled, it should be possible to send an ICMP ping to the P328 receiver from a PC on the same network, if
one wishes to test that. No actual services are enabled on Ethernet by default however though, so to make practical use of
Ethernet support, one must also enable a service.
As of the writing of this document, the only Ethernet service implemented is the PORTI virtual serial port. Additional types of
Ethernet services may be implemented in future firmware versions.
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Receiver Operation
The PORTI virtual serial port allows a listening TCP port to be opened, which will act just like a local serial port of the
receiver would. Only one TCP client may be connected at a time.
Important Note: Enabling “PORTI” on Ethernet should only be done with the P328 connected to a trusted network, since it
gives full access to the receiver just as a local serial port would, and has no authentication or security mechanisms.
To enable the PORTI service, use the command
$JETHERNET,PORTI,port
where port is replaced with the TCP port number which one wishes to use. Any port in the range 1 to 65535 is allowable,
but it is recommended one consider which TCP port numbers are typically reserved for various common protocols and avoid
those port numbers.
To disable the PORTI service, use the command
$JETHERNET,PORTI,OFF
Topic Last Updated: v1.07 / February 16, 2017
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Current Version: v1.09/January 8, 2018
Page 79
Commands and Messages
Commands and Messages Overview
The receiver supports a selection of NMEA 0183 messages, proprietary messages that conform to NMEA 0183
standards, and Hemisphere GNSS proprietary binary messages. It is your decision as a systems designer whether or
not to support a NMEA 0183-only software interface or a selection of both NMEA 0183 and binary messages.
All Crescent and Eclipse receivers are configured with NMEA 0183 commands and can output NMEA 0183 messages. In
addition to NMEA 0183, some receivers can be configured using NMEA 2000 commands and can output NMEA 2000
messages.
Commands
•
General operation and configuration commands
•
GNSS commands
•
SBAS commands
•
e-Dif commands
•
Vector commands and messages
•
GLONASS commands and messages
•
DGPS base station commands
•
Local differential and RTK commands and messages
•
Beacon receiver commands and messages
•
L-band commands
•
RAIM commands
Messages
•
Data messages
•
Binary messages
•
NMEA 2000 CAN messages
Topic Last Updated: v1.07 / February 16, 2017
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Commands and Messages
NMEA 0183 Message Format
NMEA 0183 messages (sentences) have the following format:
$XXYYY,ZZZ,ZZZ,ZZZ...*CC
where:
Element
Description
$
Message header character
XX
NMEA 0183 talker field (GP = GPS, GL = GLONASS, GA = GALILEO, GB =
BEIDOU, GN = All constellations)
YYY
Type of GPS NMEA 0183 message
ZZZ
Variable length message fields
*CC
Checksum
Carriage return
Line feed
Null (empty) fields occur when there is no information for that field. You can use the JNP command to specify the
number of decimal places output in the GPGGA and GPGLL messages.
What does mean?
The literal translation means "Carriage Return, Line Feed." They are terms used in computer programming languages to
describe the end of a line or string of text. If you are writing your own communication software for a receiver, see some of
the examples below. If you are already using a program such as Hemisphere GNSS' PocketMax, when you click to send a
command to the receiver, the program adds the carriage return and line feed to the end of the text string for you. If you are
using HyperTerminal or other terminal software, typically the Enter key on your keyboard is set to send the
pair. You may need to define this in the setup section of the terminal software. Some software may treat the Enter key on
your numeric keypad differently than the main Enter key in the main QWERTY section of the keyboard – use the main
Enter key for best results.
Originally, the carriage return and line feed characters were for use with printers. The carriage return character would
signal the printer to send the print head back to the left edge of the page on the current line of text. The line feed
command instructed the printer to advance the paper one line. Today, electronics often use the carriage return and line
feed instructions to signify the end of a string of text, prompting the device to process the string and execute the
instructions sent in the text string.
Electronics use different ways to represent the characters. In ASCII numbers, is represented as 13 in
decimal, or 0D in hexadecimal. ASCII for is 10 decimal, or 0A hexadecimal. Some computer languages use
different ways to represent . Unix and C language can use “\x0D\x0A". C language can also use “\r\n” in some
instances. Java may use CR+LF. In Unicode, carriage return is U+000D, and line feed is U+000A. It is advised to clearly
understand how to send these characters if you are writing your own interface software.
Topic Last Updated: v1.07 February 16, 2017
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Current Version: v1.09/January 8, 2018
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Commands and Messages
Command/Query/Message Types
General Operation and Configuration Commands
The following table lists the commands related to the general operation and configuration of the receiver.
Command
Description
JAIR
Specify how the receiver will respond to the
dynamics associated with airborne applications
JALT
Turn altitude aiding for the receiver on or off
JAPP
Specify or query receiver application firmware
JASC,D1
Set the RD1 diagnostic information message from
the receiver to on or off
JASC,VIRTUAL
Configure the receiver to have RTCM data input on
one port and output through the other (when using
an external correction source)
JBAUD
Specify the baud rates of the receiver or query the
current setting
JBIN
Enable the output of the various binary messages
supported by the receiver
JCONN
Create a virtual circuit between the A and B ports to
enable communication through the receiver to the
device on the opposite port
JDIFF
Specify or query the differential mode of the receiver
JDIFF,AVAILABLE
Query the receiver for the differential types currently
being received
JDIFFX,EXCLUDE
Specify the differential sources to be excluded from
operating in a multi-diff application
JDIFFX,GNSSOUT
Specify GNSS output in correction formats or query
the current setting
JDIFFX,INCLUDE
Specify the differential sources to be allowed to
operate in a multi-diff application
JDIFFX,SOURCE
Query the receiver for the differential source
JDIFFX,TYPE
Query the receiver for the differential type
JEPHOUT,PERIODSEC
to allow ephemeris messages (95, 65, 35) to go out a
rate other than when they change
JFLASH,DIR
Display the files on a USB flash drive
JFLASH,FILE,CLOSE
Close an open file on a USB flash drive
JFLASH,FILE,NAME
Open a specific file, append to a specific file, or
display the file name of the open file on a USB flash
drive
JFLASH,FILE,OPEN
Create and open a file with an automatically
generated file name on a USB flash drive
JFLASH,FREESPACE
Display the free space in kilobytes (KB) on a USB
flash drive
JFLASH,NOTIFY,CONNECT
Enable/disable the automatic response when a USB
flash drive is inserted or removed (if port is not
specified the response will be sent to the port that
issued the command)
JFLASH,QUERYCONNECT
Manually verify if a USB flash drive is connected or
disconnected
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Commands and Messages
JFORCEAPP
Force an application to be used in a multi-application
(MFA)
JI
Display receiver information, such as its serial
number and firmware version
JK
Subscribe the receiver to various options, such as
higher update rates, e-Dif (or base station capability)
or L-Dif; or query for the current subscription
expiration date when running Atlas application or the
receiver subscription code when running all other
applications
JK,SHOW
contain authorization information
JLIMIT
Set the threshold of estimated horizontal
performance for which the DGPS position LED is
illuminated or query the current setting
JMODE
Query receiver for status of JMODE settings
JMODE,BASE
Enable/disable base mode functionality or query the
current setting
JMODE,FIXLOC
Set the receiver to not re-average (or re-average) its
position or query the current setting
JMODE,FOREST
Turn the higher gain functionality (for tracking under
canopy) on/off or query the current setting
JMODE,GLOFIX
Enable/disable use of RTCM v3 (RTK) GLONASS
correctors
JMODE,GPSONLY
Set the receiver to use GPS data in the solution or
query the current setting (if GLONASS is available,
setting to YES will cause the receiver to only use
GPS data)
JMODE,L1ONLY
Set the receiver to use L1 data even if L2 data is
available or query the current setting
JMODE,MIXED
Include satellites that do not have differential
corrections in the solution
JMODE,NULLNMEA
Enable/disable output of NULL fields in NMEA 0183
messages when no there is no fix (when position is
lost)
JMODE,SBASNORTK
Disable/enable the use of SBAS ranging signals
(carrier phase) in RTK
JMODE,SBASR
Enable/disable SBAS ranging
JMODE,STRICTRTK
Use this command to invoke stricter checks on whether
RTK fix is declared. Forces float of RTK at 30 seconds
of Age-of-Diff
JMODE,SURETRACK
Enable/disable SureTrack functionality (default is
enabled) or query the current setting
JMODE,SURVEY
Assure RTK fix is not declared when residual errors
exceed 10 cm. Also forces use of GLONASS and
prevents SureTrack operation.
JMODE,TIMEKEEP
Enable/disable continuous time updating in NMEA
0183 messages when there is no fix (when position
is lost)
JMODE,TUNNEL
Enable/disable faster reacquisition after coming out
of a tunnel or query the current setting
JPOS
Speed up the initial acquisition when changing
continents with the receiver or query the receiver for
the current position of the receiver
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Commands and Messages
JPPS,FREQ
Specify the pps frequency of the receiver or query
the current setting
JPPS,WIDTH
Specify the pps width of the receiver or query the
current setting
JPRN,EXCLUDE
For advanced users only.
Exclude GPS and/or other GNSS satellites from
being used in the positioning solution or query the
current setting
JQUERY,GUIDE
Query the receiver for its determination on whether
or not it is providing suitable accuracy after both the
SBAS and GPS have been acquired (up to five
minutes)
JQUERY,TEMPERATURE
Query the receiver’s temperature
JRELAY
Send user-defined text out of a serial port
JRESET
Reset the receiver to its default operating parameters
by turning off outputs on all ports, saving the
configuration, and setting the configuration to its
defaults
JSAVE
Send this command after making changes to the
operating mode of the receiver
JSHOW
Query the current operating configuration of the
receiver
JSHOW,ASC
Query receiver for current ASCII messages being
output
JSHOW,BIN
Query receiver for current Bin messages being
output
JSHOW,CONF
Query receiver for configuration settings
JSHOW,GP
Query the receiver for each GP message currently
being output through the current port and the update
rate for that message
JSHOW,THISPORT
Query to determine which receiver port you are
connected to
JSYSVER
Returns the boot loader version from the GPS card
JT
Query the receiver for its GPS engine type
Note: Use the JSAVE command to save changes you need to keep and wait for the $>SAVE COMPLETE
response.
Topic Last Updated: v1.07 / February 16, 2017
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Current Version: v1.09/January 8, 2018
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Commands and Messages
GNSS Commands
The following table lists the commands supported by the internal GNSS engine for its configuration and operation.
Command
Description
JAGE
Specify maximum DGPS (COAST) correction age (6 to 8100 seconds)
JASC,GN
Enable the GPS data messages at a particular update rate to be turned on or off
JMASK
Specify the elevation cutoff mask angle for the GPS engine
JNMEA,PRECISION
Specify or query the number of decimal places to output in the GPGGA and the GPGLL
messages or query the current setting
JNP
Specify the number of decimal places output in the GPGGA and GPGLL messages
JOFF
Turn off all data messages being output through the current port or other port
JOFF,ALL
Turn off all data messages being output through all ports
JSMOOTH
Set the carrier smoothing interval (15 to 6000 seconds) or query the current setting
JTAU,COG
Set the course over ground (COG) time constant (0.00 to 3600.00 seconds) or query
the current setting
JTAU,SPEED
Set the speed time constant (0.00 to 3600.00 seconds) or query the current setting
Note: Use the JSAVE command to save changes you need to keep and wait for the $>SAVE COMPLETE response.
The following table lists the messages applicable to GNSS
Message
Description
Bin16
GNSS code and phase observation information
Bin19
GNSS Tracking Information
Topic Last Updated: v1.07/ February 16, 2017
SBAS Commands
The following table lists the commands supported by the SBAS demodulator for its control and operation.
Command
Description
JASC,D1
Set the RD1 diagnostic information message from the receiver to on or off
JASC,RTCM
Configure the receiver to output RTCM version 2 DGPS corrections from SBAS or beacon
through either receiver serial port
JGEO
Display information related to the current frequency of SBAS and its location in relation to the
receiver’s antenna
JWAASPRN
Change the SBAS PRNs in memory or query the receiver for current PRNs in memory
Note: Use the JSAVE command to save changes you need to keep and wait for the $>SAVE COMPLETE
response.
Topic Last Updated: v1.00 / August 11, 2010
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Current Version: v1.09/January 8, 2018
Page 85
Commands and Messages
e-Dif Commands
The following table lists the commands supported by the e-Dif application for its control and operation.
Command
Description
JRAD,1
Display the current reference position in e-Dif applications only
JRAD,1,LAT,LON,HEIGHT
Use this command—a derivative of the JRAD,1,P command—when absolute
positioning is required in e-Dif applications only
JRAD,1,P
e-Dif: Record the current position as the reference with which to compute e-Dif
corrections. This would be used in relative mode as no absolute point information is
specified.
DGPS Base Station: Record the current position as the reference with which to
compute Base Station corrections in e-Dif applications only. This would be used in
relative mode as no absolute point information is specified
JRAD,2
Forces the receiver to use the new reference point (you normally use this command
following a JRAD,1 type command)
JRAD,3
Invoke the e-Dif function once the unit has started up with the e-Dif application active,
or, update the e-Dif solution (calibration) using the current position as opposed to the
reference position used by the JRAD,2 command
JRAD,7
Turn auto recalibration on or off
Note: Use the JSAVE command to save changes you need to keep and wait for the $>SAVE COMPLETE response.
Topic Last Updated: v1.02 / January 25, 2011
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Current Version: v1.09/January 8, 2018
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Commands and Messages
Vector Commands and Messages
The following table lists the commands related to the GPS heading aspect of the Vector OEM heading system.
Command
Description
JASC
Turn on different messages
JASC,INTLT
Configure the receiver to output pitch and roll data (pitch and roll are factory calibrated over
temperature to be accurate to ±3°C)
JASC,PASHR
Configure the receiver to output time, true heading, roll, and pitch data in one message
JASC,PTSS1
Configure the receiver to output heave, pitch, and roll in the commonly used TSS1 message
format
JATT,COGTAU
Set the course over ground (COG) time constant (0.0 to 3600.0 seconds) or query the current
setting
JATT,CSEP
Query for the current separation between GPS antennas
JATT,EXACT
Enable/disable internal filter reliance on the entered antenna separation or query the current
setting
JATT,FLIPBRD
Turn the flip feature on/off (allowing you to install the Crescent Vector board upside down) or
query the current feature status
JATT,GYROAID
Turn gyro aiding on or off or query the current setting
JATT,HBIAS
Set the heading bias or query the current setting
JATT,HELP
Show the available commands for GPS heading operation and status
JATT,HIGHMP
Set/query the high multipath setting for use in poor GPS environments
JATT,HRTAU
Set the heading rate time constant or query the current setting
JATT,HTAU
Set the heading time constant or query the current setting
JATT,LEVEL
Turn level operation on or off or query the current setting
JATT,MOVEBASE
Set the auto GPS antenna separation or query the current setting
JATT,MSEP
Manually set the GPS antenna separation or query the current setting
JATT,NEGTILT
Turn the negative tilt feature on or off or query the current setting
JATT,NMEAHE
Instruct the Crescent Vector to preface the HDG, HDM, HDT, and ROT messages with GPor
HE
JATT,PBIAS
Set the pitch/roll bias or query the current setting
JATT,PTAU
Set the pitch time constant or query the current setting
JATT,ROLL
Configure the Crescent Vector for roll or pitch GPS antenna orientation
JATT,SEARCH
Force the Crescent Vector to reject the current GPS heading solution and begin a new search
JATT,SPDTAU
Set the speed time constant (0.0 to 3600.0 seconds) or query the current setting
JATT,SUMMARY
Display a summary of the current Crescent Vector settings
JATT,TILTAID
Turn tilt aiding on or off or query the current setting
JATT,TILTCAL
Calibrate tilt aiding or query the current feature status
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Commands and Messages
The following table lists Vector messages.
Message
Description
GNGSA
GNSS DOP and active satellites
GPDTM
Datum reference
GPGGA
GPS fix data
GPGLL
Geographic position - latitude/longitude
GPGNS
GNSS fix data
GPGRS
GNSS range residuals
GPGST
GNSS pseudorange error statistics
GPGSV
GNSS satellite in view
GPHDG/HEHDG
Provide magnetic deviation and variation for calculating magnetic or true heading
GPHDM/HEHDM
Provide magnetic heading of the vessel derived from the true heading calculated
GPHDT/HEHDT
Provide true heading of the vessel
GPHEV
Heave value in meters
GPRMC
Recommended minimum specific GNSS data
GPROT/HEROT
Contains the vessel’s rate of turn (ROT) information
GPRRE
Range residual message
GPVTG
Course over ground and ground speed
GPZDA
Time and date
PASHR
Time, true heading, roll, and pitch data in one message
PSAT,GBS
Satellite fault detection used for RAIM
PSAT,HPR
Proprietary NMEA sentence that provides the true heading, pitch/roll information and time ina
single message
PSAT,INTLT
Proprietary NMEA sentence that provides the title measurement from the internal inclinometer
(in degrees)
TSS1
Heave, pitch, and roll message in the commonly used TSS1 message format
Topic Last Updated: v1.07 / Octoter 13, 2016
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Commands and Messages
GLONASS Commands and Messages
The following table lists the commands applicable to GLONASS-capable receivers.
Command
Description
JASC,GL
Enable the GLONASS data messages at a particular update rate to be turned on or off.
When turning messages on, various update rates are available depending on the
requirements.
JMODE,GPSONLY
Set the receiver to use GPS data in the solution or query the current setting (if
GLONASS is available, setting to YES will cause the receiver to only use GPS data)
JNMEA,GGAALLGNSS
Configure the GGA string to include full GNSS information (the number of used
GLONASS satellites will be included in the GPGGA message) or query the current
setting
The following table lists the messages applicable to GLONASS-capable receivers.
Message
Description
Bin16
GALILEO GNSS code and phase observation information
Bin62
GLONASS almanac information
Bin65
GLONASS ephemeris information
Bin66
GLONASS L1 code and carrier phase information
Bin69
GLONASS L1 diagnostic information
GLMLA
GLONASS almanac data - contains complete almanac data for one GLONASS satellite (multiple
sentences may be transmitted, one for each satellite in the GLONASS constellation)
Topic Last Updated: v1.02 / January 25, 2011
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Commands and Messages
GALILEO Commands and Messages
The following table lists the commands applicable to GALILEO-capable receivers.
Command
Description
JASC,GAGSV
Enable/disable the data for GALILEO satellites in view. When turning messages on,
various update rates are available depending on the requirements.
JASC,GNGNS
Enable/disable fix data for GNSS systems including GALILEO (GAGNS). When turning
messages on, various update rates are available depending on the requirements.
JMODE,GPSONLY
Set the receiver to use GPS data in the solution or query the current setting (if GALILEO
is available, setting to YES will cause the receiver to only use GPS data)
JNMEA,GGAALLGNSS
Configure the GGA string to include full GNSS information (the number of used satellites
will be included in the GPGGA message) or query the current setting
The following table lists the messages applicable to GALILEO-capable receivers.
Message
Description
Bin45
GALILEO ephemeris information
Bin16
GALILEO GNSS code and phase observation information
Bin44
GALILEO time conversion information
*Note: For observations in tracking status, see GNSS, Bin 16 & Bin 19.
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Commands and Messages
QZSS Commands and Messages
The following table lists the commands applicable to QZSS-capable receivers.
Command
Description
JASC,GQGSV
Enable/disable the data for QZSS satellites in view.
JASC,GNGNS
Enable/disable fix data for GNSS systems.
JASC,GNGSA
DOP and active satellite information
The following table lists the binary messages applicable to QZSS-capable receivers.
Message
Description
Bin16
GNSS code and phase observation information
Bin19
GNSS diagnostic information
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Commands and Messages
DGPS Base Station Commands
The following table lists the commands supported by the base station feature for its control and operation.
Command
Description
JRAD,1
Display the current reference position in e-Dif applications only
JRAD,1,LAT,LON,HEIGHT
Use this command—a derivative of the JRAD,1,P command—when absolute
positioning is required in e-Dif applications only
JRAD,1,P
e-Dif: Record the current position as the reference with which to compute e-Dif
corrections. This would be used in relative mode as no absolute point information is
specified.
DGPS Base Station: Record the current position as the reference with which to
compute Base Station corrections in e-Dif applications only. This would be used in
relative mode as no absolute point information is specified
JRAD,9
Initialize the Base Station feature and use the previously entered point, either with
$JRAD,1,P or $JRAD,1,LAT,LON,HEIGHT, as the reference with which to compute
Base Station corrections in e-Dif applications only. Use this for both relative mode
and absolute mode.
JRAD,10
Specify BDS message to be transmitted by base station
Topic Last Updated: v1.02 / January 25, 2011
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Commands and Messages
Local Differential and RTK Commands and Messages
The following table lists the commands supported by Local Differential (L-Dif) and RTK feature for its control and operation.
Command
Description
JASC,CMR
Set the proprietary CMR messages to on or off to provide corrections to the rover
(only applies to an Eclipse base station receiver when using GPS dual frequency
RTK mode)
JASC,DFX
Set the proprietary DFX messages to on or off to provide corrections to the rover
(only applies to a Crescent base receiver when using L-Dif or RTK mode)
JASC,ROX
Set the proprietary ROX messages to on or off to provide corrections to the rover
(only applies to an Eclipse base station receiver when using GPS dual frequency
RTK mode)
JASC,RTCM3
Set the RTCM version 3 messages to on or off to provide corrections to the rover
(only applies to an Eclipse base station receiver when using GPS dual frequency
RTK mode)
JASC,PSAT,BLV,1
Configure the receiver to output the North,East,Up base-line vector
JASC,PSAT,FVI,1
Configure the receiver to output a message include most position and attitude
information
JASC,PSAT,RTKPROG
Configure the receiver to output RTK fix progress
JASC,PSAT,RTKSTAT
Configure the receiver to output the most relevant parameters affecting RTK
JASC,PSAT,VCT,1
Configure the receiver to output the heading, pitch, roll, and master to slave vector
JMODE,BASE
Enable/disable base mode functionality or query the current setting
JNMEA,PRECISION
Specify or query the number of decimal places to output in the GPGGA andthe
GPGLL messages or query the current setting
JNP
Specify the number of decimal places output in the GPGGA and GPGLLmessages
JQUERY,RTKPROG
Perform a one-time query of RTK fix progress information
JQUERY,RTKSTAT
Perform a one-time query of the most relevant parameters that affect RTK
JRTK,1
Show the receiver’s reference position (can issue command to base station or rover)
JRTK,1,LAT,LON,HEIGHT
Set the receiver’s reference position to the coordinates you enter (canissue
command to base station or rover)
JRTK,1,P
Set the receiver’s reference coordinates to the current calculated position if you do
not have known coordinates for your antenna location (can issue command to base
station or rover)
JRTK,5
Show the base station’s transmission status for RTK applications (can issue
command to base station)
JRTK,5,Transmit
Suspend or resume the transmission of RTK (can issue command to base station)
JRTK,6
Display the progress of the base station (can issue command to base station)
JRTK,12
Disable or enable the receiver to go into fixed integer mode (RTK) vs. float mode (LDif) - can issue command to rover
JRTK,17
Display the transmitted latitude, longitude, and height of the base station (can issue
command to base station or rover)
JRTK,18
Display the distance from the rover to the base station, in meters (can issue
command to rover)
JRTK,18,BEARING
Display the bearing from the base station to the rover, in degrees (can issue
command to rover)
JRTK,18,NEU
Display the distance from the rover to the base station and the delta North, East, and
Up, in meters (can issue command to rover)
JRTK,28
Set the base station ID transmitted in ROX/DFX/CMR/RTCM3 messages (can issue
command to base station)
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Commands and Messages
JRTCM3, ANTNAME
Specify the antenna name that is transmitted in various RTCM3 messages from the
base
JRTCM3, EXCLUDE
Specify RTCM3 message types to not be transmitted (excluded) by base station
JRTCM3, INCLUDE
Specify RTCM3 message types to be transmitted by base station
JRTCM3, NULLANT
Specify the antenna name as null (no name) that is transmitted in various RTCM3
messages from the base
The following table lists the Local Differential (L-Dif) and RTK messages.
Message
Description
PSAT,RTKPROG
Contains RTK fix progress information
PSAT,RTKSTAT
Contains the most relevant parameters affecting RTK
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Commands and Messages
Beacon Receiver Commands and Messages
If integrating a Hemisphere GNSS SBX beacon module with the receiver GNSS engine, Hemisphere GNSS recommends
interfacing the beacon receiver to Port D of the receiver engine. Hemisphere GNSS has implemented some command
and message pass-through intelligence for such an integration. In this configuration you can issue the commands in the
following table to the beacon receiver through either Port A, Port B, or Port C of the receiver. When you issue queries to
the SBX primary communications port, the response messages are output interspersed with RTCM correction information.
This may cause conflicts with a GNSS receiver’s ability to compute differential corrected solutions. By sending these
queries to the SBX secondary communications port the flow of RTCM corrections on the primary port will not be
interrupted.
The following table lists the beacon commands/messages found in this Help file.
Query
NMEA 0183 Query Type
Description
GPCRQ,MSK
Standard
Query the SBX for its operational status
GPCRQ,MSS
Standard
Query the SBX for its performance status
GPMSK
Standard
Tune beacon the receiver and turn on diagnostic information
PCSI,0
Hemisphere GNSS
proprietary
Query the SBX to output a list of available proprietary PCSI
commands
PCSI,1
Hemisphere GNSS
proprietary
Query the SBX for a selection of parameters related to the
operational status of its primary channel
PCSI,1,1
Hemisphere GNSS
proprietary
Obtain beacon status information from the SBX beacon engine
inside the receiver
PCSI,2
Hemisphere GNSS
proprietary
Query the SBX to output a selection of parameters related to the
operational status of its secondary channel
PCSI,3,1
Hemisphere GNSS
proprietary
Query the SBX to output the search information used for beacon
selection in Automatic Beacon Search mode. The output has three
frequencies per line.
PCSI,3,2
Hemisphere GNSS
proprietary
Display the ten closest beacon stations
PCSI,3,3
Hemisphere GNSS
proprietary
Display the contents of the beacon station database
PCSI,4
Hemisphere GNSS
proprietary
Clear search history in Auto mode
PCSI,5
Hemisphere GNSS
proprietary
Set the baud rate of Port0 and Port1
PCSI,6
Hemisphere GNSS
proprietary
Reboot SBX receiver
PCSI,7
Hemisphere GNSS
proprietary
Swap modes on the receiver
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Commands and Messages
The following table lists the beacon messages found in this Help file.
Message
Description
CRMSK
Operational status message of SBX
CRMSS
Performance status message of SBX
Topic Last Updated: v1.06 / March 10, 2015
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Commands and Messages
Atlas® Commands
The following tables lists the commands accepted by the Atlas-band receiver to configure and monitor the Atlas
functionality of the receiver.
Command
Description
$JI
Requests the serial number and firmware version number
from the receiver
Requests the authorization from the receiver
Is used to send the authorization to the receiver
$JK
$JASC,GPGGA,1
Requests receiver to output GGA positions at 1Hz.
$JASC,RD1,1
EnablesAtlas Diagnostic message output
$JDIFF,LBAND,SAVE
EnablesAtlas mode for tracking the Atlas communication
satellites
Enables the Atlas solution in the receiver
$JDIFF,INCLUDE,ATLAS
$JFREQ,AUTO
Automatically sets theAtlas parameters to track the Atlas
communication satellites
$JATLAS,LIMIT
Configure the accuracy threshold for when the NMEA
0183 GPGGA message reports a quality indicator of 4.
See $JATLAS,LIMIT, section for more detail
Saves issued commands
$JSAVE
Note: Use the JSAVE command to save changes you need to keep and wait for the $J>SAVE COMPLETE
response.
If your Atlas communication is working properly the following should apply:
o
o
o
Bit Error Rate: less than 10-10
Spot Beam Freq:
▪
AMERICAS: 1545.5300
▪
APAC: 1539.8525
▪
EMEA: 1540.9525
Nav Condition: FFFFF
If this is not the case, then enter the following commands in the Receiver Command Page, one at a time:
Command
$JFREQ,AUTO
$JDIFF,LBAND,SAVE
$JFREQ,AUTO
$JDIFF,LBAND,SAVE
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Commands and Messages
RAIM Commands
RAIM (Receiver Autonomous Integrity Monitoring) is a GNSS integrity monitoring scheme that uses redundant ranging
signals to detect a satellite malfunction resulting in a large range error. The Hemisphere GNSS products use RAIM to alert
users when errors have exceeded a user-specified tolerance. RAIM is available for SBAS, and Beacon, applications.
The following table lists the available RAIM commands.
Command
Description
JRAIM
Specify the parameters of the RAIM scheme that affect the output of the PSAT,GBS
message or query the current setting
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Commands and Messages
Data Messages
Note: Output rates greater than 1Hz may require a subscription. Output rates greater than 20 Hz are not available for
all products. Please refer to your product’s documentation for the supported output rates.
For messages supporting rates greater than 1 Hz, see the following table:
Firmware
Version
Support Output Rates
50 Hz
50, 25, 10, 5, 2, 1, .2, 0
20 Hz
20, 10, 5, 4, 2, 1, .2, .5, 0
For message descriptions and maximum rates see the following table:
Message
Maximum
Rate
Description
GNGSA
1 Hz
GPS DOP and active satellite information
GPALM
1 Hz
GPS almanac data
GPGGA
50 Hz
Detailed GPS position information
GPGLL
50 Hz
Latitude and longitude data
GPGNS
50 Hz
Fixes data for single or combined satellite navigation systems
GPGRS
50 Hz
Supports Receiver Autonomous Integrity Monitoring (RAIM)
GPGST
1 Hz
GNSS pseudorange error statistics
GPGSV
1 Hz
GNSS satellite in view
GPHDG/HEHDG
50 Hz
Magnetic deviation and variation for calculating magnetic or true heading
GPHDM/HEHDM
50 Hz
Magnetic heading of the vessel derived from the true heading calculated
GPHDT/HEHDT
50 Hz
True heading of the vessel
GPHEV
50 Hz
Heave value in meters
GPRMC
50 Hz
Recommended minimum specific GNSS data
GPROT/HEROT
50 Hz
Vessel’s rate of turn (ROT) information
GPRRE
1 Hz
Range residual message
GPVTG
50 Hz
Course over ground and ground speed
GPZDA
50 Hz
UTC time and date information
PASHR
1 Hz
Time, true heading, roll, and pitch data in one message
PSAT,ATTSTAT
1HZ
PSAT,GBS
1 Hz
Used to support Receiver Autonomous Integrity Monitoring (RAIM)
PSAT,HPR
50 Hz
Proprietary NMEA message that provides the true heading, pitch, roll, and
time in a single message
PSAT,INTLT
1 Hz
Proprietary NMEA message that provides the tilt measurements from the
internal inclinometers (in degrees)
PSAT,RTKPROG
1 Hz
Contains RTK fix progress information
PSAT,RTKSTAT
1 Hz
Contains the most relevant parameters affecting RTK
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Commands and Messages
RD1
1 Hz
SBAS diagnostic information
TSS1
50 Hz
Heave, pitch, and roll message in the commonly used TSS1 message format
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Commands and Messages
Binary Messages
Message Structure
The binary messages supported by the receiver are in an Intel Little Endian format for direct read in a PC
environment. More information on this format at the following web site:
http://www.cs.umass.edu/~verts/cs32/endian.html
Each binary message begins with an 8-byte header and ends with a carriage return, line feed pair (0x0D, 0x0A). The
first four characters of the header is the ASCII sequence $BIN.
The following table provides the general binary message structure.
Component
Description
Type
Bytes
Values
Header
Synchronization String
4 byte
string
4
$BIN
Block ID - type of binary
message
Unsigned
short
2
1, 2, 80, 93,
94, 95, 96, 97,
98, or 99
DataLength - the length of
the binary messages
Unsigned
short
2
52, 16, 40, 56,
96, 128, 300,
28, 68, or 304
Data
Binary Data - varying fields
of data with a total length
of DataLength bytes
Mixed
fields
52, 16,
40, 56,
96, 128,
300, 28,
68, or 304
Varies - see
message
tables
Epilogue
Checksum - sum of all
bytes of the data (all
DataLength bytes); the
sum is placed in a 2-byte
integer
Unsigned
short
2
Sum of data
bytes
CR- Carriage return
Byte
1
0D hex
LF - Line feed
Byte
1
0A hex
Messages
Message
Description
Bin1
GPS position message (position and velocity data)
Bin2
GPS DOPs (Dilution of Precision)
Bin3
Lat/Lon/Hgt, Covariances, RMS, DOPs and COG, Speed, Heading
Bin5
Base station information
Bin16
All constellation code and phase information
Bin 19
GNSS diagnostic information
Bin35
BeiDou ephemeris information
Bin36
BeiDou code and carrier phase information (all frequencies)
Bin44
GALILEO time conversion
Bin45
GALILEO ephemeris
Bin62
GLONASS almanac information
Bin65
GLONASS ephemeris information
Bin66
GLONASS L1/L2 code and carrier phase information
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Bin69
GLONASS L1/L2 diagnostic information
Bin76
GPS L1/L2 code and carrier phase information
Bin80
SBAS data frame information
Bin89
SBAS satellite tracking information
Bin93
SBAS ephemeris information
Bin94
Ionospheric and UTC conversion parameters
Bin95
GPS ephemeris information
Bin96
GPS L1 code and carrier phase information
Bin97
Processor statistics
Bin98
GPS satellite and almanac information
Bin99
GPS L1 diagnostic information
Bin100
GPS L2 diagnostic information
Bin122
Alternate position solution data
Bin209
SNR and status for all GNSS tracks
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Commands and Messages
NMEA 2000 CAN Messages
Message
Description
GNSSPositionData
Detailed GPS position information
GNSSPositionRapidUpdates
Abbreviated GPS position information
NMEACogSogData
GPS speed and direction information
Topic Last Updated: v1.00 / August 11, 2010
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Commands and Messages
GPCRQ
GPCRQ,MSK Command
Command
Type
Beacon Receiver
Description
Standard NMEA 0183 query to prompt the SBX for its operational status (response is the CRMSK message)
You can issue this command through the secondary serial port with a standard response issued to the same
port. This will not affect the output of RTCM data from the main serial port when the receiver has acquired a
lock on a beacon station.
Command
Format
$GPCRQ,MSK
$CRMSK,fff.f,X,ddd,Y,n*CC
Receiver
Response
Example
where
Response
Component
Description
fff.f
Frequency in kHz (283.5 to 325)
X
Tune mode (M = manual, A = automatic, D = database)
ddd
MSK bit rate (100 or 200 bps)
Y
MSK rate selection mode (M = manual, A = automatic, D = database)
n
Period of output of CRMSS performance status message (0 to 100 seconds)
Response example:
$CRMSK,322.0,M,100,A,2*CC
The frequency is 322.0 kHz, tune mode is Manual, MSK bit rate is 100 bps, MSK rate selection mode is
Automatic, and the message is output every 2 seconds.
Additional
Information
Topic Last Updated: v1.04 / May 29, 2012
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Commands and Messages
GPCRQ,MSS Command
Command
Type
Beacon Receiver
Description
Standard NMEA 0183 query to prompt the SBX for its performance status (response is the CRMSS
message)
You can issue this command through the secondary serial port with a standard response issued to the same
port. This will not affect the output of RTCM data from the main serial port when the receiver has acquired a
lock on a beacon station.
Command
Format
$GPCRQ,MSS
$CRMSS,xx,yy,fff.f,ddd*CC
Receiver
Response
Example
where
Response
Component
Description
xx
Signal strength in dBμV/m
yy
Signal-to-noise ratio (SNR) in dB
fff.f
Frequency in kHz (283.5 to 325)
ddd
MSK bit rate in bps (100 or 200)
Response example:
$CRMSS,65,36,322.0,100*CC
The signal strength is 65 dBμV/m, SNR is 36 dB, frequency is 322.0 kHz, and MSK bit rate is 100 bps.
Additional
Information
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Commands and Messages
GPMSK Command
Command
Type
Beacon Receiver
Description
Beacon Tune command
Instruct the SBX to tune to a specified frequency and automatically select the correct MSK rate. When you
send this command through Port A, Port B, or Port C, it is automatically routed to Port D. The resulting
confirmation of this message is returned to the same port from which you sent the command.
Command
Format
$GPMSK,fff.f,F,mmm,M[,n]
where:
Command/Response
Component
Description
fff.f
Beacon frequency in kHz (283.5 to 325)
This may be left blank if the following field 'F' is set to 'A' (automatic) or 'D'
(database)
F
Frequency selection mode
(M = manual, A = automatic, D = database)
mmm
MSK bit rate
This may be left blank if the following field 'M' is set to 'A' (automatic) or 'D'
(database)
M
MSK rate selection mode
(M = manual, A = automatic, D = database)
n
Period of output of CRMSS performance status message (0 to 100 seconds),
where leaving the field blank will output the message once
Note: This field is optional when using database tuning mode or automatic
tuning mode.
$CRMSS,xx,yy,fff.f,ddd*CC
Receiver
Response
Example
where
Response
Component
Description
xx
Signal strength in dBμV/m
yy
Signal-to-noise ratio (SNR) in dB
fff.f
Frequency in kHz (283.5 to 325)
ddd
MSK bit rate in bps (100 or 200)
To instruct the SBX to tune to 310.5 kHz with a bit rate of 100 and output the CRMSS message every 20
seconds issue the following command:
$GPMSK,310.5,M,100,M,20
...and the receiver response is:
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Commands and Messages
$CRMSS,65,36,310.5,100*CC
(repeating every n=20 seconds)
If using database tuning mode issue the following command:
$GPMSK,,D,,D
If using automatic tuning mode issue the following command:
$GPMSK,,A,,A
Additional
Information
When the SBX acknowledges this message, it immediately tunes to the specified frequency and
demodulates at the specified rate.
When you set 'n' to a non-zero value, the SBX outputs the CRMSS message at that period through the
serial port from which the SBX was tuned. When you issue this command with a non-zero 'n' value through
Port B, the periodic output of the CRMSS performance status message does not impact the output of RTCM
on Port A. However, when tuning the SBX with a non-zero 'n' value through Port A, the CRMSS message is
interspersed with the RTCM data. Most GPS engines will not be able to filter the CRMSS message, causing
the overall data to fail parity checking. When power to the SBX is removed and reapplied, the status output
interval resets to zero (no output).
When tuning the SBX engine, if the 'n' field in this message is non-zero, the CRMSS message output by the
SBX may interrupt the flow of RTCM data to the GPS receiver. Repower the SBX to stop the output of the
CRMSS message or retune the Beacon receiver with 'n' set to zero.
Topic Last Updated: v1.02 / January 25, 2011
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JAGE Command
Command
Type
GPS
Description
Specify maximum DGPS (COAST) correction age (6 to 8100 seconds). Using
COAST technology, the receiver can use old correction data for extended
periods of time.
The default setting for the receiver is 2700 seconds.
If you select a maximum correction age older than 1800 seconds (30
minutes), test the receiver to ensure the new setting meets the requirements,
as accuracy will slowly drift with increasing time.
Command
Format
Receiver
Response
Example
$JAGE,age
where 'age' is the maximum differential age timeout
$>
To set the DGPS correction age to 60 seconds issue the following command:
$JAGE,60
Additional
Information
To query the receiver for the current DGPS correction age, issue the JSHOW
command.
What does mean?
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Commands and Messages
JAIR Command
Command
Type
General Operation and Configuration
Description
Specify how the receiver will respond to the dynamics associated with
airborne applications or query the current setting
Command
Format
Specify how the receiver responds
$JAIR,r
where 'r' is the AIR mode:
•
NORM - normal track and nav filter bandwidth
•
HIGH - highest track and nav filter bandwidth (receiver is
optimized for the high dynamic environment associated with
airborne platforms)
•
LOW - lowest track and nav filter bandwidth
•
AUTO - default track and nav filter bandwidth, similar to
NORM but automatically goes to HIGH above 30 m/sec
Query the current setting
$JAIR
Receiver
Response
Receiver response when specifying how the receiver responds or querying
the current setting
$>JAIR,MAN,NORM
$>JAIR,MAN,HIGH
$>JAIR,MAN,LOW
$>JAIR,AUTO,NORM
Example
To set the AIR mode to LOW issue the following command:
$JAIR,LOW
The response is then:
$>JAIR,MAN,LOW
Additional
Information
Defaults to normal (NORM) which is recommended for most applications.
The AUTO option enables the receiver to decide when to turn JAIR to HIGH.
CAUTION: Setting AIR mode to HIGH is not recommended for Crescent
Vector operation.
On the HIGH setting, the receiver tolerates larger and sudden drops in the
SNR value before it discards the data as being invalid. This additional
tolerance is beneficial in applications such as crop dusting where an aircraft
is banking rapidly. As the aircraft banks, the antenna position shifts from
upright and having a clear view of the sky to being tipped slightly, with a
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possibly obscured view of the sky, and then back to upright. This sudden
tipping of the antenna causes the SNR value to drop.
If the tolerance is not set as HIGH, the receiver views the data recorded while
banking as invalid and discards it. As a result the GPS position will not be
accurate.
The status of this command is also output in the JSHOW message.
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Commands and Messages
JALT Command
Command
Type
General Operation and Configuration
Description
Turn altitude aiding for the receiver on or off
When set to something other than NEVER, altitude aiding uses a fixed altitude instead of using one satellite’s
observations to calculate the altitude. The advantage of this feature, when operating in an application where a
fixed altitude is acceptable, is that the extra satellite’s observations can be used to the betterment of the latitude,
longitude, and time offset calculations, resulting in improved accuracy and integrity. Marine markets, for example,
may be well suited for use of this feature.
Command
Format
$JALT,c[,h[,GEOID]]
where 'c' (feature status variable) and 'h' (threshold variable) may be one of the following:
c Value
Correspondi
ng h Value
Description
NEVER
N/A
Default
mode of
operation
where
altitude
aiding is
not used.
SOMETIMES
PDOP
Sets the
receiver to
use altitude
aiding
depending
upon the
PDOP
threshold.
SATS
NUMSATS
Sets the
receiver to
use altitude
aiding
depending
upon the
number of
visible
satellites. If
there are
fewer visible
satellites
than
specified by
NUMSATS,
altitude
aiding is
used.
ALWAYS
HEIGHT
Sets the
receiver to
use altitude
aiding
regardless
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Format
$JALT,NEVER
$JALT,SOMETIMES,PDOP
$JALT,SATS,NUMSATS
$JALT,ALWAYS,HEIGHT
$JALT,ALWAYS,HEIGHT,GEOID
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Commands and Messages
of a
variable. In
this case,
you may
specify the
ellipsoidal
altitude
HEIGHT
that the
receiver
should use.
To obtain a HEIGHT value to use with ALWAYS (using DGPS positions), average the HEIGHT over a period of
time (the longer the time period, the more accurate this HEIGHT value). This is the ellipsoidal height.
$JALT,ALWAYS,HEIGHT
If you use the height reported from the GPGGA message (this is actually geoidal and not ellipsoidal), use the
following command:
$JALT,ALWAYS,HEIGHT,GEOID
Receiver
Response
Example
$>
To turn altitude aiding on to SOMETIMES with a PDOP of 5 issue the following command:
$JALT,SOMETIMES,5
7
To turn altitude aiding on to ALWAYS using the height of 401.6 m as reported in the GPGGA message (geoidal
height) issue the following command:
$JALT,ALWAYS,401.6,GEOID
Additional
Information
To query the receiver for the current setting, issue the JSHOW command. For example, if you issue the following
command:
$JALT,ALWAYS,404.2
...then issuing the JSHOW command displays the following as part of its output:
$>JSHOW,ALT,ALWAYS,404.2
Topic Last Updated: v1.03 / January 11, 2012
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Commands and Messages
JAPP Command
Command
Type
General Operation and Configuration
Description
Specify which of the installed applications should be utilized or query the receiver
for the currently installed applications
Note: Hemisphere GNSS Crescent and Eclipse GPS receivers are able to hold
up to two different application firmware programs simultaneously.
Command
Format
Specify receiver application firmware (when two applications are present)
$JAPP,OTHER or $JAPP,O
(the second command uses the letter O, not a zero) or
$JAPP,x
where ‘x’ is either 1 (application in slot 1) or 2 (application in slot 2)
Query receiver application firmware
$JAPP
Receiver
Response
For example, if WAAS (SBAS) and AUTODIFF (e-Dif) are the two installed
applications (WAAS in slot1 and AUTODIFF in slot2) and WAAS is the current
application, if you issue the $JAPP,OTHERcommand on a
receiver, the response to $JAPP will
be$>JAPP,AUTODIFF,WAAS,2,1, indicating that application slot 2 (eDif) is currently being used.
Hemisphere GNSS recommends that you follow up the sending of these
commands with a $JAPP query to see which application is 1 or 2. It is best to
use these two commands when upgrading the firmware inside the receiver,
because the firmware upgrading utility uses the application number to designate
which application to overwrite.
Response to querying the current setting
$>JAPP,CURRENT,OTHER,[1 OR 2],[2 OR 1]
where:
•
'CURRENT' indicates the current application in use
•
'OTHER' indicates the secondary application that is not
currently in use
•
1 and 2 indicate in which application slots the applications
reside
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Example
If the response
to $JAPP is $>JAPP,WAAS,AUTODIFF,1,2, this
indicates:
•
WAAS (SBAS) is the current application and is in application slot 1
•
e-Dif is the other application (not currently used) and is in application slot 2
Additional
Information
When querying the current setting, the following application names may
appear (depending on your product):
•
Crescent
WAAS – Changes to the SBAS application. For the sake of the application names, the SBAS application is referred to as
WAAS by the receiver’s internal firmware
• AUTODIFF – Changes to the e-Dif application. Referred to as "AUTODIFF" in the receiver’s
internal firmware
• LOCRTK – Changes to the local differential rover application
• RTKBAS – Changes to the local differential base application
• LBAND – Changes toAtlas DGPS service
•
Eclipse
WAASRTKB – Changes to the SBAS/RTK Base application
• LBAND – Changes to Atlas DGPS service
•
RTK – Changes to the RTK Rover application
• Eclipse II
SBASRTKB – Changes to the SBAS/L-band/RTK Base application
• AUTODIFF – Changes to the e-Dif application, referred to as "AUTODIFF" in the firmware
• RTK – Changes to the RTK Rover application
• MFA - Multi-function application
• miniEclipse
WAASRTKB – Changes to the SBAS/RTK Base application
• AUTODIFF – Changes to the e-Dif application, referred to as "AUTODIFF" in the firmware
• RTK – Changes to the RTK Rover application
• MFA - Multi-function application
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JASC
JASC Command Overview
The JASC command is used to request ASCII messages.
Command
Description
JASC,CMR
Set the proprietary CMR messages to on or off to provide corrections to the rover
JASC,D1 (RD1)
Set the RD1 diagnostic information message from the receiver to on or off
JASC,DFX
Set the proprietary DFX messages to on or off to provide corrections to the rover
JASC,GL
Enable the GLONASS data messages at a particular update rate to be turned on or
off. When turning messages on, various update rates are available depending on the
requirements.
JASC,GN
Enable the GNSS data messages at a particular update rate to be turned on or off.
When turning messages on, various update rates are available depending on the
requirements.
JASC,GP
Enable the GPS data messages at a particular update rate to be turned on or off
JASC,INTLT
Configure the receiver to output pitch and roll data
JASC,PASHR
Configure the receiver to output time, true heading, roll, and pitch data in one
message
JASC,PSAT,ATTSTAT
Configure the receiver to output the information of secondary antenna
JASC,PSAT,BLV,1
Configure the receiver to output the North,East,Up base-line vector
JASC,PSAT,FVI,1
Configure the receiver to output a message include most position and
attitude information
JASC,PSAT,RTKPROG
Configure the receiver to output RTK fix progress
JASC,PSAT,RTKSTAT
Configure the receiver to output the most relevant parameters affecting RTK
JASC,PSAT,VCT,1
Configure the receiver to output the heading, pitch, roll, and master to slave vector
JASC,PTSS1
Configure the receiver to output heave, pitch, and roll in the commonly used TSS1
message format
JASC,ROX
Set the proprietary ROX messages to on or off to provide corrections to the rover
JASC,RTCM
Configure the receiver to output RTCM version 2 DGPS corrections from SBAS or
beacon through either receiver serial port
JASC,RTCM3
Set the RTCM version 3 messages to on or off to provide corrections to the rover
JASC,VIRTUAL
Configure the receiver to have RTCM data input on one port and output through the
other (when using an external correction source)
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Commands and Messages
JASC,CMR Command
Command
Type
Local Differential and RTK
Description
Set the proprietary CMR messages to on or off to provide corrections to the
rover
This command only applies to an Eclipse base station receiver when using
GPS dual frequency RTK mode. RTK is relative to the reference position
(base only).
Command
Format
Receiver
Response
Example
$JASC,CMR,r[,OTHER]
where:
•
'r' = correction status variable (0 = turn corrections Off, 1 =
turn corrections On)
•
',OTHER' = optional field, enacts a change on the current
port when you send the command without it (and without
the brackets) and enacts a change on the other port when
you send the command with it (without the brackets). See
Configuring the Data Message Output for detailed
information on 'THIS' and 'OTHER' port terminology.
$>
To turn on CMR messages on the OTHER port issue the following command:
$JASC,CMR,1,OTHER
Additional
Information
To query the receiver for the current setting, issue the JSHOW command.
To change the broadcast station ID, use JRTK,28.
Topic Last Updated: v1.02 / January 25, 2011
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Commands and Messages
JASC,D1 Command
Command
Type
General Operation and Configuration, SBAS
Description
Set the RD1 diagnostic information message from the receiver to on or off
There is currently only an (R)D1 message.
Command
Format
Receiver
Response
Example
$JASC,D1,r[,OTHER]
where:
•
'r' = message rate (0 = Off, 1 = On at 1Hz)
•
',OTHER' = optional field, enacts a change in the RD1
message on the current port when you send the command
without it (and without the brackets) and enacts a change in
the RD1 message on the other port when you send the
command with it (without the brackets). See Configuring the
Data Message Output for detailed information on 'THIS' and
'OTHER' port terminology.
$>
To output the RD1 message once per second from THIS port issue the
following command:
$JASC,D1,1
...and the output will look similar to the following:
$RD1,410213,1052,1551.489,1,0,39,- 611.5,0,1F,1F,0,999999
$RD1,410214,1052,1551.489,1,0,40,615.1,0,1F,1F,0,999999
$RD1,410215,1052,1551.489,1,0,40,607.1,0,1F,1F,0,999999
See RD1 message for a description of each field in the response.
Additional
Information
Although you request D1 through this command the responding message is
RD1.
To query the receiver for the current setting, issue the JSHOW command.
For example, if you issue the following command:
$JASC,D1,1
...then issuing the JSHOW command displays the following as part of its
output:
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$>JSHOW,ASC,D1,1
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JASC,DFX Command
Command
Type
Local Differential and RTK
Description
Set the proprietary DFX messages to on or off to provide corrections to the
rover
This command only applies to a Crescent base receiver when using L-Dif or
RTK mode. Differential is relative to the reference position (base only). See
the JASC,ROX command for the equivalent message for the Eclipse series of
products.
Command
Format
$JASC,DFX,r[,OTHER]
where:
•
'r' = correction status variable (0 = turn corrections Off, 1 =
turn corrections On)
•
',OTHER' = optional field, enacts a change on the current
port when you send the command without it (and without
the brackets) and enacts a change on the other port when
you send the command with it (without the brackets). See
Configuring the Data Message Output for detailed
information on 'THIS' and 'OTHER' port terminology.
Receiver
Response
$>
Example
To turn on DFX messages on THIS port issue the following command:
$JASC,DFX,1
Additional
Information
To query the receiver for the current setting, issue the JSHOW command.
To change the broadcast station ID, use JRTK,28.
Topic Last Updated: v1.02 / January 25, 2011
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Commands and Messages
JASC,GL Command
Command
Type
GLONASS
Description
Enable the GLONASS data messages at a particular update rate to be turned on or off. When turning
messages on, various update rates are available depending on therequirements.
Command
Format
$JASC,msg,r[,OTHER]
where:
•
'msg' = name of the data message
•
'r' = message rate (see table below)
•
',OTHER' = optional field, enacts a change on the current port (THIS port) whenyou
send the command without it (and without the brackets) and enacts a change on the
other port (OTHER port) when you send the command with it (without the brackets).
See Configuring the Data Message Output for detailed information on 'THIS' and
'OTHER' port terminology.
Send a command with a zero value for the 'R' field to turn off a message.
Receiver
Response
Example
MSG
R (rate in Hz)
Description
GLMLA
1 (on) or 0 (off)
When set to on the
message is sent once
(one message for each
tracked satellite) and
then sent again
whenever satellite
information changes
GLONASS almanac data
GLGGA
20, 10, 2, 1, 0 or .2
GPS fix data
GLGLL
20, 10, 2, 1, 0 or .2
Geographic position - latitude/longitude
GLGNS
20, 10, 2, 1, 0 or .2
GNSS fix data
GLGSA
1 or 0
GLONASS DOP and active satellites
GLGSV
1 or 0
GLONASS satellite in view
$>
To output the GLGNS message through the OTHER port at a rate of 20 Hz, issue the following command:
$JASC,GLGNS,20,OTHER
Additional
Information
The status of this command is also output in the JSHOW message.
What does mean?
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Updated: v1.02 / January 25, 2011
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JASC,GA Command
Command
Type
GALILEO
Description
Enable the GALILEO data messages at a particular update rate to be turned on or off. When turning
messages on, various update rates are available depending on the requirements.
Command
Format
$JASC,msg,r[,OTHER]
where:
•
'msg' = name of the data message
•
'r' = message rate (see table below)
•
',OTHER' = optional field, enacts a change on the current port (THIS port) whenyou
send the command without it (and without the brackets) and enacts a change on the
other port (OTHER port) when you send the command with it (without the brackets).
See Configuring the Data Message Output for detailed information on 'THIS' and
'OTHER' port terminology.
Send a command with a zero value for the 'R' field to turn off a message.
Receiver
Response
MSG
R (rate in Hz)
Description
GNGNS
20, 10, 2, 1, 0 or .2
All GNSS fix data (GAGNS output is GALILEO)
GAGSV
1 or 0
GALILEO satellites in view
$>
Example
To output the GAGNS message through the OTHER port at a rate of 20 Hz, issue the following command:
Additional
Information
The status of this command is also output in the JSHOW message.
What does mean?
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JASC,GQ Command
Command
Type
QZSS
Description
Enable the QZSS data messages at a particular update rate to be turned on or off.
Command
Format
$JASC,msg,r[,OTHER]
where:
•
'msg' = name of the data message
•
'r' = message rate (see table below)
•
',OTHER' = optional field, enacts a change on the current port (THIS port) when you
send the command without it (and without the brackets) and enacts a change onthe
other port (OTHER port) when you send the command with it (without the brackets).
See Configuring the Data Message Output for detailed information on 'THIS' and
'OTHER' port terminology.
Send a command with a zero value for the 'R' field to turn off a message.
MSG
GQGSV
Receiver
Response
Example
R (rate in Hz)
Description
1 or 0
QZSS satellites in view
$>
To output the GAGNS message through the OTHER port, issue the following command:
$JASC,GNGNS,1,OTHER
Additional
Information
The status of this command is also output in the JSHOW message.
What does mean?
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JASC,GN Command
Command
Type
GPS, Vector
Description
Enable the GNSS data messages at a particular update rate to be turned on or off. When turning messages
on, various update rates are available depending on therequirements.
Command
Format
$JASC,msg,r[,OTHER]
where:
•
'msg' = name of the data message
•
'r' = message rate (see table below)
•
',OTHER' = optional field, enacts a change on the current port (THIS port) when you
send the command without it (and without the brackets) and enacts a change on the
other port (OTHER port) when you send the command with it (without the brackets).
See Configuring the Data Message Output for detailed information on 'THIS' and
'OTHER' port terminology.
Send a command with a zero value for the 'R' field to turn off a message.
Receiver
Response
Example
MSG
R (rate in Hz)
Description
GNGGA
20, 10, 2, 1, 0 or .2
GNSS fix data
GNGLL
20, 10, 2, 1, 0 or .2
Geographic position - latitude/longitude
GNGNS
20, 10, 2, 1, 0 or .2
GNSS fix data
GNGSA
1 or 0
GNSS DOP and active satellites
$>
To output the GNGNS message through the OTHER port at a rate of 20 Hz, issue the following command:
$JASC,GNGNS,20,OTHER
Additional
Information
The status of this command is also output in the JSHOW message.
What does mean?
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Commands and Messages
JASC,GP Command
Command
Type
GPS, Vector
Description
Enable the GPS data messages at a particular update rate to be turned on or off. When turning messages
on, various update rates are available depending on therequirements.
Command
Format
$JASC,msg,r[,OTHER]
where:
•
'msg' = name of the data message
•
'r' = message rate (see table below)
•
',OTHER' = optional field, enacts a change on the current port (THIS port) when you
send the command without it (and without the brackets) and enacts a change on the
other port (OTHER port) when you send the command with it (without the brackets).
See Configuring the Data Message Output for detailed information on 'THIS' and
'OTHER' port terminology.
Send a command with a zero value for the 'R' field to turn off a message.
MSG
R (rate in Hz)
Description
GPALM
1 or 0
GPS almanac data
GPDTM
1 or 0
Datum reference
GPGBS
1 or 0
Satellite fault detection used for RAIM
GPGGA
20, 10, 2, 1, 0 or .2
Detailed GPS position information
GPGLL
20, 10, 2, 1, 0 or .2
Latitude and longitude data
GPGNS
20, 10, 2, 1, 0 or .2
Fixes data for single or combined satellite navigation
systems
GPGRS
1, 0 or .2
GNSS range residuals
GNGSA
1 or 0
GPS DOP and active satellite information
GPGST
1 or 0
GNSS pseudorange error statistics
GPGSV
1 or 0
GNSS satellite in view
GPHDG
or
HEHDG
20, 10, 2, 1, 0 or .2
Magnetic deviation and variation for calculating magnetic
or true heading
GPHDM
or
HEHDM
20, 10, 2, 1, 0 or .2
Magnetic heading of the vessel derived from the true
heading calculated
GPHDT
or
HEHDT
20, 10, 2, 1, 0 or .2
True heading of the vessel
GPHEV
20, 10, 2, 1, 0 or .2
Heave value in meters
GPHPR
20, 10, 2, 1, 0 or .2
Proprietary NMEA message that provides the true
heading, pitch, roll, and time in a single message
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Commands and Messages
Receiver
Response
Example
GPRMC
10, 2, 1, 0 or .2
Recommended minimum specific GNSS data
GPROT
or
HEROT
20, 10, 2, 1, 0 or .2
Vessel’s rate of turn (ROT) information
GPRRE
1 or 0
Range residual message
GPVTG
20, 10, 2, 1, 0 or .2
Course over ground and ground speed
GPZDA
20, 10, 2, 1, 0 or .2
UTC time and date information
INTLT
1 or 0
Proprietary NMEA message that provides the tilt
measurements from the internal inclinometers (in
degrees)
$>
To output the GPGGA message through the OTHER port at a rate of 20 Hz, issue the following command:
$JASC,GPGGA,20,OTHER
Additional
Information
The status of this command is also output in the JSHOW message.
What does mean?
Topic Last Updated: v1.06 / March 10, 2015
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Commands and Messages
JASC,INTLT Command
Command
Type
Vector
Description
Configure the receiver to output pitch and roll data (pitch and roll are factory
calibrated over temperature to be accurate to ±3°C)
Saved with JSAVE.
Command
Format
$JASC,INTLT,r[,OTHER]
where:
•
'r' = message rate (0 = Off, 1 = On at 1Hz)
•
',OTHER' = optional field, enacts a change on the current
port when you send the command without it (and without
the brackets) and enacts a change on the other port when
you send the command with it (without the brackets). See
Configuring the Data Message Output for detailed
information on 'THIS' and 'OTHER' port terminology.
$PSAT,INTLT,pitch,roll*CC
Receiver
Response
where pitch and roll are in degrees
Example
Additional
Information
PSAT,INTLT message
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Commands and Messages
JASC,PASHR Command
Command
Type
Vector
Description
Configure the receiver to output time, true heading, heave, roll, and pitch data in one message
Command
Format
Receiver
Response
$JASC,PASHR,r[,OTHER]
where:
•
'r' = message rate (0 = Off, 1 = On at 1Hz)
•
',OTHER' = optional field, enacts a change on the current port when you send the command without it
(and without the brackets) and enacts a change on the other port when you send the command with it
(without th brackets). See Configuring the Data Message Output for detailed information on 'THIS' and
'OTHER' port terminology.
$PASHR,hhmmss.ss,HHH.HH,T,RRR.RR,PPP.PP,heave,rr.rrr,pp.ppp,hh.hhh,QF*CC
<
where:
Example
Message
Component
Description
hhmmss.ss
UTC time
HHH.HH
Heading value in decimal degrees
T
True heading (T displayed if heading is relative to true north)
RRR.RR
Roll in decimal degrees (- sign will be displayed when applicable)
PPP.PP
Pitch in decimal degrees (- sign will be displayed when applicable)
heave
Heave, in meters
rr.rrr
Roll standard deviation in decimal degrees
pp.ppp
Pitch standard deviation in decimal degrees
hh.hhh
Heading standard deviation in decimal degrees
QF
Quality Flag
•
0 = No position
•
1 = All non-RTK fixed integer positions
•
2 = RTK fixed integer position
*CC
Checksum
Carriage return
Line feed
To turn on the PASHR message on THIS port issue the following command:
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$JASC,PASHR,1
...and the message output appears similar to the following:
$PASHR,162930.00,,T,2.48,3.92,-0.64,0.514,0.514,0.000,1*05
$PASHR,162931.00,,T,2.38,3.93,-0.70,0.508,0.508,0.000,1*07
$PASHR,162932.00,,T,2.67,4.00,-0.66,0.503,0.503,0.000,1*04
Additional
Information
PASHR message
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Commands and Messages
JASC,PSAT,ATTSTAT Command
Command
Type
Local Differential and RTK
Description
The information of secondary antenna.
Command
Format
$JASC,PSAT,ATTSTAT,r[,OTHER]
where:
•
'r' = message rate (0 = Off, 1 = On at 1Hz)
•
',OTHER' = optional field, enacts a change on the current
port when you send the command without it (and without
the brackets) and enacts a change on the other port when
you send the command with it (without the brackets). See
Configuring the Data Message Output for detailed
information on 'THIS' and 'OTHER' port terminology.
.
Receiver
Response
Example
$>
To turn on this message on the THIS port issue the following command:
$JASC,PSAT,ATTSTAT,1
Additional
Information
Issuing the JSAVE command after setting JASC,PSAT,ATTSTAT to 1
(message on at 1Hz) does not save this setting. You must enable
JASC,PSAT,ATTSTAT (set it to 1) each time you power on the receiver.
Related
Commands
and
Messages
PSAT,ATTSTAT message
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Commands and Messages
JASC,PSAT,BLV Command
Command
Type
Local Differential and RTK
Description
Configure the receiver to output the North, East,Up base-line vector
Command
Format
$JASC,PSAT,BLV,r[,OTHER]
where:
•
•
'r' = message rate 0,1,2,5,10,20 (0 = Off, 1 = On at 1Hz)
',OTHER' = optional field, enacts a change on the current
port when you send the command without it (and without
the brackets) and enacts a change on the other port when
you send the command with it (without the brackets). See
Configuring the Data Message Output for detailed
information on 'THIS' and 'OTHER' port terminology.
.
Receiver
Response
Example
$>
To turn on this message on the THIS port issue the following command:
$JASC,PSAT,BLV,1
Additional
Information
.
Related
Commands
and
Messages
PSAT, BLV message
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Commands and Messages
JASC,PSAT,FVI Command
Command
Type
Local Differential and RTK
Description
Contains much more special information
Command
Format
$JASC,PSAT,FVI,r[,OTHER]
where:
•
•
'r' = message rate 0,1,2,5,10,20 (0 = Off, 1 = On at 1Hz)
',OTHER' = optional field, enacts a change on the current
port when you send the command without it (and without
the brackets) and enacts a change on the other port when
you send the command with it (without the brackets). See
Configuring the Data Message Output for detailed
information on 'THIS' and 'OTHER' port terminology.
.
Receiver
Response
Example
$>
To turn on this message on the THIS port issue the following command:
$JASC,PSAT,FVI,1
Additional
Information
.
Related
Commands
and
Messages
PSAT, FVI message
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Commands and Messages
JASC,PSAT,RTKPROG Command
Command
Type
Local Differential and RTK
Description
Configure the receiver to output RTK fix progress
Command
Format
$JASC,PSAT,RTKPROG,r[,OTHER]
where:
•
'r' = message rate (0 = Off, 1 = On at 1Hz)
•
',OTHER' = optional field, enacts a change on the current
port when you send the command without it (and without
the brackets) and enacts a change on the other port when
you send the command with it (without the brackets). See
Configuring the Data Message Output for detailed
information on 'THIS' and 'OTHER' port terminology.
You can also perform a one-time query of the message information by
issuing the JQUERY,RTKPROG command.
Receiver
Response
Example
$>
To turn on this message on the THIS port issue the following command:
$JASC,PSAT,RTKPROG,1
Additional
Information
Issuing the JSAVE command after setting JASC,PSAT,RTKPROG to 1
(message on at 1Hz) does not save this setting. You must enable
JASC,PSAT,RTKPROG (set it to 1) each time you power on the receiver.
See also PSAT,RTKPROG message.
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Commands and Messages
JASC,PSAT,RTKSTAT Command
Command
Type
Local Differential and RTK
Description
Configure the receiver to output the most relevant parameters affecting RTK
Command
Format
$JASC,PSAT,RTKSTAT,r[,OTHER]
where:
•
'r' = message rate (0 = Off, 1 = On at 1Hz)
•
',OTHER' = optional field, enacts a change on the current
port when you send the command without it (and without
the brackets) and enacts a change on the other port when
you send the command with it (without the brackets). See
Configuring the Data Message Output for detailed
information on 'THIS' and 'OTHER' port terminology.
You can also perform a one-time query of the message information by
issuing the JQUERY,RTKSTAT command.
Receiver
Response
Example
$>
To turn on this message on the THIS port issue the following command:
$JASC,PSAT,RTKSTAT,1
Additional
Information
Issuing the JSAVE command after setting JASC,PSAT,RTKSTAT to 1
(message on at 1Hz) does not save this setting. You must enable
JASC,PSAT,RTKSTAT (set it to 1) each time you power on the receiver.
Related
Commands
and
Messages
JQUERY,RTKSTAT command
PSAT,RTKSTAT message
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Commands and Messages
JASC,PSAT,VCT Command
Command
Type
Local Differential and RTK
Description
Command
Format
$JASC,PSAT,VCT,r[,OTHER]
where:
•
•
'r' = message rate 0,1,2,5,10,20 (0 = Off, 1 = On at 1Hz)
',OTHER' = optional field, enacts a change on the current
port when you send the command without it (and without
the brackets) and enacts a change on the other port when
you send the command with it (without the brackets). See
Configuring the Data Message Output for detailed
information on 'THIS' and 'OTHER' port terminology.
.
Receiver
Response
Example
$>
To turn on this message on the THIS port issue the following command:
$JASC,PSAT,VCT,1
Additional
Information
Related
Commands
and
Messages
.
PSAT, VCT message
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Commands and Messages
JASC,PTSS1 Command
Command
Type
Vector
Description
Configure the receiver to output heave, pitch, and roll in the commonly used TSS1 message format
Command
Format
Receiver
Response
$JASC,PTSS1,r[,OTHER]
where:
•
'r' = message rate (in Hz) of 0 (off), 0.25, 0.5, 1, 2, 4, 5, 10, or 20 (if subscribed)
•
',OTHER' = optional field, enacts a change on the current port when you send the command without it
(and without the brackets) and enacts a change on the other port when you send the command with it
(without the brackets). See Configuring the Data Message Output for detailed information on 'THIS' and
'OTHER' port terminology.
:XXAAAASMHHHHQMRRRRSMPPPP*CC
where:
Message
Component
Description
XX
Horizontal acceleration
AAAA
Vertical acceleration
HHHH
Heave, in centimeters
S
S = space character
M
Space if positive; minus if negative
Q
Status flag
Value
Description
h
Heading aided mode (settling) The System is receiving heading aiding signals from a gyrocompass but is still
awaiting the end of the three minutes settling period after power-on or a change of
mode or heave bandwidth. The gyrocompass takes approximately five minutes to
settle after it has been powered on. During this time, gyrocompass aiding of the
System will not be perfect. The status flag does NOT indicate this condition.
F
Full aided mode (settled condition) - The System is receiving and using aiding
signals from a gyrocompass and from a GPS receiver or a Doppler log.
M
Space if positive; minus if negative
RRRR
Roll, in units of 0.01 degrees (ex: 1000 = 10°)
S
S = space character
M
Space if positive; minus if negative
PPPP
Pitch, in units of 0.01 degrees (ex: 1000 = 10°)
Carriage return
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Additional
Information
Line feed
TSS1 message
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Commands and Messages
JASC,ROX Command
Command
Type
Local Differential and RTK
Description
Set the proprietary ROX messages to on or off to provide corrections to the
rover
This command only applies to an Eclipse base station receiver when using
GPS dual frequency RTK mode. RTK is relative to the reference position
(base only).
Command
Format
Receiver
Response
Example
$JASC,ROX,r[,OTHER]
where:
•
'r' = correction status variable (0 = turn corrections Off, 1 =
turn corrections On)
•
',OTHER' = optional field, enacts a change on the current
port when you send the command without it (and without
the brackets) and enacts a change on the other port when
you send the command with it (without the brackets). See
Configuring the Data Message Output for detailed
information on 'THIS' and 'OTHER' port terminology.
$>
To turn on ROX messages on the OTHER port issue the following command:
$JASC,ROX,1,OTHER
Additional
Information
To query the receiver for the current setting, issue the JSHOW command.
To change the broadcast station ID, use JRTK,28.
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Commands and Messages
JASC,RTCM Command
Command
Type
SBAS
Description Configure the receiver to output RTCM version 2 DGPS corrections from
SBAS or beacon through either receiver serial port. The correction data
output is RTCM SC-104, even though SBAS uses a different over-the-air
protocol (RTCA).
Command
Format
Receiver
Response
Example
$JASC,RTCM,r[,OTHER]
where:
•
'r' = message status variable (0 = Off, 1 = On)
•
',OTHER' = optional field, enacts a change on the current
port when you send the command without it (and without
the brackets) and enacts a change on the other port when
you send the command with it (without the brackets). See
Configuring the Data Message Output for detailed
information on 'THIS' and 'OTHER' port terminology.
$>
To output RTCM corrections from SBAS or beacon on THIS port (current
port) issue the following command:
$JASC,RTCM,1
Additional
Information
To verify the current setting is on, issue the JSHOW command. You will see
output similar to the following:
$>JSHOW,ASC,RTCM,1.0
If the current setting is off, the JSHOW command will not show any
information for this setting.
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Commands and Messages
JASC,RTCM3 Command
Command
Type
Local Differential and RTK
Description
Set the RTCM version 3 messages to on or off to provide corrections to the
rover
This command only applies to an Eclipse base station receiver when using
GPS dual frequency RTK mode. RTK is relative to the reference position
(base only).
Command
Format
Receiver
Response
Example
$JASC,RTCM3,r[,OTHER]
where:
•
'r' = correction status variable (0 = turn corrections Off, 1 =
turn corrections On)
•
',OTHER' = optional field, enacts a change on the current
port when you send the command without it (and without
the brackets) and enacts a change on the other port when
you send the command with it (without the brackets). See
Configuring the Data Message Output for detailed
information on 'THIS' and 'OTHER' port terminology.
$>
To turn on RTCM3 messages on the OTHER port issue the following
command:
$JASC,RTCM3,1,OTHER
Additional
Information
To query the receiver for the current setting, issue the JSHOW command.
To change the broadcast station ID, use JRTK,28.
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Commands and Messages
JASC,VIRTUAL Command
Command
Type
General Operation and Configuration
Description
Configure the receiver to have RTCM data input on one port and output
through the other (when using an external correction source)
For example, if RTCM is input on Port B, the data will be output through Port
A having corrected the receiver position. The receiver acts as a pass-through
for the RTCM data. Either port may be configured to accept RTCM data
input; this command enables the opposite port to output the RTCM data.
Command
Format
Receiver
Response
Example
$JASC,VIRTUAL,r[,OTHER]
where:
•
'r' = message status variable (0 = Off, 1 = On)
•
',OTHER' = optional field, enacts a change on the current
port when you send the command without it (and without
the brackets) and enacts a change on the other port when
you send the command with it (without the brackets). See
Configuring the Data Message Output for detailed
information on 'THIS' and 'OTHER' port terminology.
$>
To configure THIS port to output RTCM messages that are being input
through the OTHER port issue the following command:
$JASC,VIRTUAL,1
Additional
Information
Topic Last Updated: v1.02 / January 25, 2011
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Commands and Messages
JATT
JATT Command Overview
The JATT command is used to define or query attitude settings for Vector products.
Command
Description
JATT,COGTAU
Set the course over ground (COG) time constant (0.0 to 3600.0 seconds) or query
the current setting
JATT,CSEP
Query to retrieve the current separation between GPS antennas
JATT,EXACT
Enable/disable internal filter reliance on the entered antenna separation or query
the current setting
JATT,FLIPBRD
Allow upside down installation
JATT,GYROAID
Turn on gyro aiding or query the current feature status
JATT,HBIAS
Set the heading bias or query the current setting
JATT,HELP
Show the available commands for GPS heading operation and status
JATT,HIGHMP
Set/query the high multipath setting for use in poor GPS environments
JATT,HRTAU
Set the rate of turn time constant or query the current setting
JATT,HTAU
Set the heading time constant or query the current setting
JATT,LEVEL
Turn on level operation or query the current feature status
JATT,MOVEBASE
Set the auto GPS antenna separation or query the current setting
JATT,MSEP
Set (manually) the GPS antenna separation or query the current setting
JATT,NEGTILT
Turn on the negative tilt feature or query the current setting
JATT,NMEAHE
Instruct the Vector to preface the HDG, HDT, ROT and THS messages with GP or
HE, and the HDM message with GP or HC.
JATT,PBIAS
Set the pitch bias or query the current setting
JATT,PTAU
Set the pitch time constant or query the current setting
JATT,ROLL
Configure the Vector for roll or pitch output
JATT,SEARCH
Force a new RTK heading search
JATT,SPDTAU
Set the speed time constant (0.0 to 3600.0 seconds) or query the current setting
JATT,SUMMARY
Show the current configuration of the Vector
JATT,TILTAID
Turn tilt aiding on/off or query the Vector for the current status of this feature
JATT,TILTCAL
Calibrate the internal tilt sensor of the Vector
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Commands and Messages
JATT,COGTAU Command
Note: The JTAU,COG command provides identical functionality but works with Crescent and Eclipse products in addition
to Crescent Vectorproducts.
Command
Type
Vector
Description
Set the course over ground (COG) time constant (0.0 to 3600.0 seconds) or
query the current setting
This command allows you to adjust the level of responsiveness of the COG
measurement provided in the GPVTG message. The default value is 0.0
seconds of smoothing. Increasing the COG time constant increases the level
of COG smoothing.
COG is computed using only the primary GPS antenna (when using a multiantenna system) and its accuracy depends upon the speed of the vessel
(noise is proportional to 1/speed). This value is invalid when the vessel is
stationary, as tiny movements due to calculation inaccuracies are not
representative of a vessel’s movement.
Command
Format
Set the COG timeconstant
$JATT,COGTAU,cogtau
where 'cogtau' is the new COG time constant that falls within the range of 0.0
to 200.0 seconds
The setting of this value depends upon the expected dynamics of the
Crescent. If the Crescent will be in a highly dynamic environment, this value
should be set lower because the filtering window would be shorter, resulting
in a more responsive measurement. However, if the receiver will be in a
largely static environment, this value can be increased to reduce
measurement noise.
Query the current setting
$JATT,COGTAU
Receiver
Response
Additional
Information
$>
You can use the following formula to determine the COG time constant:
cogtau (in seconds) = 10 / maximum rate of change of course (in °/s)
If you are unsure about the best value for this setting, it is best to be
conservative and leave it at the default setting of 0.0 seconds.
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Commands and Messages
JATT,CSEP Command
Command
Type
Vector
Description
Query the Vector for the current calculated separation between antennas, as
solved for by the attitude algorithms
Command
Format
$JATT,CSEP
$>JATT,X,CSEP
Receiver
Response
where 'X' is the antenna separation in meters
Additional
Information
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Commands and Messages
JATT,EXACT Command
Command
Type
Vector
Description
Enable/disable internal filter reliance on the entered antenna separation or
query the current setting
Command
Format
Enable/disable internal filter reliance
To enable internal filter reliance:
$JATT,EXACT,YES
To disable internal filter reliance:
$JATT,EXACT,NO
Query the current setting
$JATT,EXACT
Receiver
Response
$>
Additional
Information
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Commands and Messages
JATT,FLIPBRD Command
Command
Type
Vector
Description
Turn the flip feature on/off or querythe current feature status
Allow the Vector OEM board to be installed upside down. You should use this
command only with the Vector Sensor and the Vector OEM board because
flipping the OEM board does not affect the antenna array that needs to
remain facing upwards. When using this command, the board needs to be
flipped about roll so the front still faces the front of the vessel.
Command
Format
Turn the flip feature on/off
To turn the flip feature on:
$JATT,FLIPBRD,YES
To turn the flip feature off (return to default mode - right side up):
$JATT,FLIPBRD,NO
Query current the current setting
$JATT,FLIPBRD
Receiver
Response
$>
Additional
Information
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Commands and Messages
JATT,GYROAID Command
Command
Type
Vector
Description
Turn gyro aiding on or off or query the current setting
The Vector’s internal gyro—enabled by default when shipped—offers two
benefits.
•
•
It shortens reacquisition times when a GPS heading is lost
because of obstruction of satellite signals. It does this by reducing
the search volume required for solution of the RTK.
It provides an accurate substitute heading for a short period
(depending on the roll and pitch of the vessel) ideally seeing the
system through to reacquisition.
For these two benefits, Hemisphere GNSS highly recommend leaving gyro
aiding on.
Exceeding rates of 90°/sec is not recommended because the gyro cannot
measure rates beyond this point. This is a new recommendation since
Hemisphere GNSS now uses gyro measurements to obtain a heading rate
measurement.
Command
Format
Turn gyro aiding on/off
To turn gyro aiding on:
$JATT,GYROAID,YES
To turn gyro aiding off:
$JATT,GYROAID,NO
Query the current setting
$JATT,GYROAID
Receiver
Response
$>
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Additional Information
Every time you power up the Vector the gyro goes through a warm-up procedure and
calibrates itself. You cannot save the resulting calibration, so the self-calibration takes place
every time the Vector is power cycled.
This self-calibration procedure takes several minutes and is the equivalent of the following
manual calibration procedure.
With the Vector unit installed:
1. Apply power and wait several minutes until it has acquired aGPS signal and is
computing heading.
2. Ensure gyroaiding is on by issuing the following command:
$JATT,GYROAID
3.
4.
Slowly spin the unit for one minute at no more than 15°/sec.
Keep the unit stationary for four minutes. Both the manual andthe self-calibration
procedures calibrate the Crescent Vector’s gyro to the same effect.
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Commands and Messages
JATT,HBIAS Command
Command
Type
Vector
Description Set the heading output from the Vector to calibrate the true heading of the
antenna array to reflect the true heading of the vessel or query the current
setting
Command
Format
Set the heading output
$JATT,HBIAS,x
where 'x' is a bias that will be added to the Vector’s heading in degrees. The
acceptable range for the heading bias is -180.0° to 180.0°. The default value
of this feature is 0.0°.
Query the current setting (current compensation angle)
$JATT,HBIAS
Receiver
Response
$>
Additional
Information
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Commands and Messages
JATT,HELP Command
Command
Type
Vector
Description
Show the available commands for GPS heading operation and status
Command
Format
Receiver
Response
$JATT,HELP
$>JATT,HELP,CSEP,MSEP,EXACT,LEVEL,HTAU,HRTAU,HBIASPBIAS,NEGTILT,ROLL,TILTAID,
TILTCAL,MAGAID,MAGCAL,MAGCLR,GYROAID,COGTAU,SPDTAU,SEARCH,SUMMARY
Additional
Information
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Commands and Messages
JATT,HIGHMP Command
Command
Type
Vector
Description
Enable/disable the high multipath setting for use in poor GPS environments
or query the current setting
Enabling HIGHMP mode may result in longer heading acquisition times in
high multipath environments. In HIGHMP mode, the Vector will not output
heading until it has good confidence in the result. In very poor environments,
this may take a few minutes or more; in normal environments, there is only a
slight increase in heading acquisition time.
Command
Format
Set the high multipath setting
To enable the high multipath setting:
$JATT,HIGHMP,YES
To disable the high multipath setting:
$JATT,HIGHMP,NO
Query the current setting
$JATT,HIGHMP
Receiver
Response
$>
Additional
Information
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Commands and Messages
JATT,HRTAU Command
Command
Type
Vector
Description
Set the rate of turn (ROT) time constant to adjust the level of responsiveness
of the ROT measurement provided in the GPROT message or query the
current setting
The default value of this constant is 2.0 seconds of smoothing. Increasing the
time constant increases the level of ROT smoothing.
Command
Format
Set the heading rate time constant
$JATT,HRTAU,hrtau
where 'hrtau' is the new time constant that falls within the range of 0.0 to
seconds
The setting of this value depends upon the expected dynamics of the vessel.
For example, if the vessel is very large and cannot turn quickly, increasing
this time is reasonable. The resulting heading would have reduced ‘noise’,
resulting in consistent values with time. However, artificially increasing this
value such that it does not agree with a more dynamic vessel could create a
lag in the ROT measurement with higher rates of turn.
Query the current setting
$JATT,HRTAU
Receiver
Response
Additional
Information
$>
You can use the following formula to determine the level of smoothing:
hrtau (in seconds) = 10 / maximum rate of the rate of turn (in °/s2)
Note: If you are unsure about the best value for the setting, leave it at the
default setting of 2.0 seconds.
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Commands and Messages
JATT,HTAU Command
Command
Type
Vector
Description Set the heading time constant to adjust the level of responsiveness of the
true heading measurement provided in the GPHDT message or query the
current setting.
For OEM boards the default value of this constant is 0.5 seconds of
smoothing (regardless of whether the gyro is enabled or disabled). For
finished products that implement an OEM board the default value may be
different—check your product's documentation for this value.
Although the gyro is enabled by default, you can disable it. Increasing the
heading time constant increases the level of heading smoothing and
increases lag only if the gyro is disabled.
Command
Format
Set the heading time constant
$JATT,HTAU,htau
where 'htau' is the new time constant that falls within the range of 0.0 to
seconds
The setting of this value depends upon the expected dynamics of the vessel.
If the vessel is very large and cannot turn quickly, increasing this time is
reasonable. The resulting heading would have reduced ‘noise’ resulting in
consistent values with time. However, artificially increasing this value such
that it does not agree with a more dynamic vessel could create a lag in the
heading measurement with higher rates of turn.
Query the current setting
$JATT,HTAU
Receiver
Response
Additional
Information
$>
You can use the following formula to determine level of heading smoothing
required when the gyro is in use:
Gyro on
htau (in seconds) = 40 / maximum rate of turn (in °/s)
Gyro off
htau (in seconds) = 10 / maximum rate of turn (in °/s)
If you are unsure about the best value for the setting, leave it at the default
setting of 2.0 seconds when the gyro is on and at 0.5 seconds when the gyro
is off.
Topic Last Updated: v1.06 / March 10, 2015
GNSS Technical Reference Manual
Current Version: v1.09/January 8, 2018
Page 158
Commands and Messages
JATT,LEVEL Command
Command
Type
Vector
Description
Turn level operation on or off or query thecurrent setting
If the Vector will be operated within ±10° of level, you may use this mode of
operation for increased robustness and faster acquisition times of the
heading solution.
Command
Format
Turn level operation on/off
To turn level operation on:
$JATT,LEVEL,YES
To turn level operation off:
$JATT,LEVEL,NO
Query the current setting
$JATT,LEVEL
Receiver
Response
$>
Additional
Information
Topic Last Updated: v1.05 / January 18, 2013
GNSS Technical Reference Manual
Current Version: v1.09/January 8, 2018
Page 159
Commands and Messages
JATT,MOVEBASE Command
Command
Type
Vector
Description
Set the auto GPS antenna separation or query the current setting
If the operation is turned on ,you do not need to set the GPS antenna
separation manually . Only multi-frequency boards are supported.
Command
Format
Turn level operation on/off
To turn movebase operation on:
$JATT,MOVEBASE,YES
To turn movebase operation off:
$JATT,MOVEBASE,NO
Query the current setting
$JATT,MOVEBASE
Receiver
Response
$>
Additional
Information
Topic Last Updated: v1.08 / June 21, 2017
GNSS Technical Reference Manual
Current Version: v1.09/January 8, 2018
Page 160
Commands and Messages
JATT,MSEP Command
Command
Type
Vector
Description
Manually enter a custom separation between antennas (must be accurate to
within 1 to 2 cm) or query the current setting
Command
Format
Set the antenna separation
Using the new center-to-center measurement, issue the following command:
$JATT,MSEP,sep
where 'sep' is the measured antenna separation entered in meters
Query the current setting
$JATT,MSEP