Novatel OM-20000053 User Manual

OM-20000053 REV 2

Software Versions 4.503 and 4.52

OM-20000053 Rev 2

MiLLennium GPSCard

Command Descriptions Manual

GPSCard

 Products NovAtel Inc.

GPSCard



MiLLennium Command Descriptions Manual

Publication Number: OM-20000053 Revision Level: 2 2001/01/16

This manual reflects Software Versions 4.503 and 4.52

Proprietary Notice

Information in this document is subject to change without notice and does not rep resent a comm itmen t on th e part of NovAtel Inc.. The software d escribed in this document is furnished under a licence agreement or non- disclosu re agreement. The software may be used or copied only in accordance with the terms of the agreement. It is against the law to copy the software on any medium except as specifically allowed in the license or non-disclosure agreement.

No part of this manual may be reproduced or transmitted in any fo rm or by any means, electronic or mechanical, including photocopying an d recording, for any purpose withou t the express written permission o f a duly author ized representative of NovAtel Inc.

The information contained within this manual is believed to be true and correct at the time of publication.

MiLLennium, NovAtel, Narrow Correlator, RT-20 and RT-2 are registered trademarks of NovAtel Inc. GPSCard, GPSAntenna, GPSolution and Pinwheel are trademarks of NovAtel Inc. All other brand names are trademarks of their respective holders.

2 MiLLennium GPSCard SW Version 4.503/4.52 Command Descriptions Manual Rev 2

Software License 10 Software Support 11 Foreword 12

Congratulations!........................................................................................................................................ 12

Scope.........................................................................................................................................................12

Prerequisites..............................................................................................................................................12

What’s New In This Manual?................................................................................................................... 12

1 Quick Start 13

1.1 Installation................. ............................................... .......................... ................................................. 13

Graphical Interface....................... ... .......................... ......................... .......................... ................13

1.2 Data Logging.......... ... .......................... ............................................... ......................... ........................14

1.3 Differential Operation.................................... ... .... ......................... .......................... ........................... 16

Establish a Data Link ...................................................................................................................16

Initialization - Reference Station..................................................................................................17

1.4 RTK Mode .................................. ................................................ ......................... ............................... 18

Data Communications Link............................... .......................... ......................... ........................ 18

System Initialization..................................................................................................................... 19

Monitoring Your RTK Output Data............................................................................................. 21

Options for Logging Differential Corrections.............................................................................. 21

Initialization - Rover Station........................................................................................................22

2 Command Descriptions 24

2.1 General.......................... .... ... .......................... ......................... ......................... ...................................24

Optional Calculation Of The Checksum...................................................................................... 25

2.2 Standard Command Tables.......................................... .......................... .............................................26

2.3 WAAS...................................... ... .... ......................... .......................... ....................... .......................... 30

2.3.1 WAAS GPSCard.................................................................................................................31

2.4 Special Data Input Commands............................................................................................................31

2.4.1 Almanac Data......................................................................................................................31

2.4.2 Differential Corrections Data..............................................................................................33

3 Data Logs 35

3.1 Output Logging...................................... .......................... ......................... ..........................................35

3.2 NovAtel Format Data Logs.................................................................................................................36

General ......................................................................................................................................... 36

ASCII Log Structure ....................................................................................................................36

Binary Log Structure .................................................................................................................... 36

3.3 RTK........................... .......................... ......................... .......................... .............................................37

3.4 NMEA Format Data Logs...................................................................................................................38

General ......................................................................................................................................... 38

3.5 GPS Time vs. Local Receiver Time................................. ... .... .... ......................... .... ... ........................38

3.6 Standard Log Tables...................................... ... .... ......................... ..................................................... 39

3.7 WAAS...................................... ... .... ......................... .......................... ....................... .......................... 43

3.7.1 WAAS GPSCard Logs........................................................................................................43

3.8 Pass-Through Logs....... ......................... .......................... ............................................... ....................43

3.8.1 Command Syntax ................................................................................................................ 44

3.8.2 ASCII Log Structure ...........................................................................................................44

3.8.3 Binary Log Structure........................................................................................................... 45

MiLLennium GPSCard SW Version 4.503/4.52 Command Descriptions Manual Rev 2 3

4 Message Formats 46

4.1 RTCA-Format Messages....... .... ......................... ............................................... .................................. 46

RTCA Standard Logs...................................................................................................................47

4.2 RTCM-Format Messages............................... .......................... ......................... .................................. 48

RTCM General Message Format ................................................................................................. 49

RTCM Standard Commands ........................................................................................................ 50

RTCM Standard Logs .................................................................................................................. 50

4.3 CMR Format Messaging..................................................................................................................... 56

Using RT-2 or RT-20 with CMR Format Messages....................................................................57

4.4 RINEX Format........................................ .... ... .......................... ......................... ..................................57

4.4.1 Commands........................................................................................................................... 58

4.4.2 Logs.....................................................................................................................................59

APPENDICES

A GPS Overview 63

A.1 GPS System Design ...........................................................................................................................63

The Space Segment ............... .......................... ... .......................... ......................... .... ...................63

The Control Segment................. ... .......................... ......................... .......................... ...................64

The User Segment... ... .... ......................... ................................................ ......................... ............ 64

A.2 Height Relationships..........................................................................................................................64

A.3 GPS Positioning.................................................................................................................................65

Single-point vs. Relative Pos iti on ing..................... ... .......................... .........................................66

Static vs. Kinematic Positioning ..................................................................................................67

Real-time vs. Post-mission Data Pro cess in g........................ .... .... ......................... .......................67

Differential Positioning................................................. .... ......................... .................................. 67

Pseudorange Algorithms ..............................................................................................................68

Pseudorange Differential Positioning........................................................................................... 68

Dual Station Differential Positioning...........................................................................................71

A.4 Carrier-Phase Algorithms................................................................................................................... 73

B Multipath Elimination Technology 75

B.1 Multipath............................................................................................................................................75

Why Does Multipath Occur?........................................................................................................75

Consequences of Multipath Reception.........................................................................................76

B.2 Hardware Solutions For Multipath Reduction................................................................................... 76

Antenna Site Selection................................................................................................................. 76

Antenna Designs...........................................................................................................................77

Antenna Ground Planes................................................................................................................78

NovAtel’s Internal Receiver Solutions for Multipath Reduction................................................. 79

C Commands Summary 81

ACCEPT.......................................................................................................................................81

ANTENNAPOWER..................................................................................................................... 83

ASSIGN........................................................................................................................................ 84

CLOCKADJUST.......................................................................................................................... 85

COMn........................................................................................................................................... 86

COMn_DTR.................................................................................................................................86

COMn_RTS..................................................................................................................................87

CONFIG....................................................................................................................................... 88

CRESET....................................................................................................................................... 89

CSMOOTH ..................................................................................................................................90

DATUM ....................................................................................................................................... 91

DGPSTIMEOUT.......................................................................................................................... 92

DIFF_PROTOCOL......................................................................................................................93

4 MiLLennium GPSCard SW Version 4.52 Command Descriptions Manual Rev 2

DYNAMICS................................................................................................................................. 94

ECUTOFF....................................................................................................................................95

EXTERNALCLOCK ...................................................................................................................96

EXTERNALCLOCK FREQUENCY ..........................................................................................98

FIX HEIGHT................................................................................................................................ 99

FIX POSITION............................................................................................................................100

FIX VELOCITY...........................................................................................................................101

FREQUENCY_OUT....................................................................................................................102

FRESET........................................................................................................................................103

HELP............................................................................................................................................104

IONOMODEL..............................................................................................................................105

LOCKOUT...................................................................................................................................106

LOG..............................................................................................................................................107

MAGVAR .................................................................................................................................... 108

MESSAGES................................................................................................................................. 110

POSAVE ......................................................................................................................................111

RESET.......................................................................................................................................... 112

RESETHEALTH..........................................................................................................................113

RESETHEALTHALL..................................................................................................................113

RINEX.......................................................................................................................................... 114

RTCM16T....................................................................................................................................115

RTCMRULE................................................................................................................................ 116

RTKMODE..................................................................................................................................117

SAVEALMA................................................................................................................................ 121

SAVECONFIG............................................................................................................................. 122

SEND............................................................................................................................................ 123

SENDHEX ................................................................................................................................... 124

SETDGPSID ................................................................................................................................125

SETHEALTH ...............................................................................................................................126

SETL1OFFSET............................................................................................................................127

SETNAV......................................................................................................................................128

SETTIMESYNC ..........................................................................................................................130

UNASSIGN.................................................................................................................................. 131

UNASSIGNALL..........................................................................................................................131

UNDULATION............................................................................................................................ 132

UNFIX.......................................................................................................................................... 133

UNLOCKOUT............................................................................................................................. 133

UNLOCKOUTALL ..................................................................................................................... 133

UNLOG........................................................................................................................................134

UNLOGALL ................................................................................................................................ 134

USERDATUM............................................................................................................................. 135

VERSION.....................................................................................................................................136

WAASCORRECTION WAAS................................................................................................. 137

D Logs Summary 138

Log Descriptions....................................... ... .... .... ............................................... ......................................138

ALMA/B Decoded Almanac.............................. .... ... ................................................ ................138

BSLA/B Baseline Measurement RTK ...................................................................................143

CDSA/B Communication and Differential Decode Status....................................................... 146

CLKA/B Receiver Clock Offset Data........................... ......................... .......................... ......... 149

CLMA/B Receiver Clock Model ..............................................................................................151

CMR Standard Logs....................................... ... .... .... ......................... .......................... ................ 153

COM1A/B and COM2A/B Pass-Through Logs .......................................................................154

DOPA/B Dilution of Precision.................................................................................................. 155

ETSA/B Extended Tracking Status...........................................................................................157

FRMA/B Framed Raw Navigation Data................................................................................... 159

GGAB Global Position System Fix Data (Binary Format Only)..............................................160

GPALM Almanac Data............................... ... .... .......................... .............................................161

MiLLennium GPSCard SW Version 4.52 Command Descriptions Manual Rev 2 5

GPGGA Global Position System Fix Data................................................................................162

GPGLL Geographic Position.................................................................................................... 163

GPGRS GPS Range Residuals for Each Satellite.....................................................................164

GPGSA GPS DOP and Active Satellites .................................................................................. 165

GPGST Pseudorange Measurement Noise Statistics................................................................166

GPGSV GPS Satellites in View................................................................................................167

GPRMB Navigation Information..............................................................................................168

GPRMC GPS Specific Information .................... ......................... .......................... ... ................169

GPVTG Track Made Good And Ground Speed........................................................................170

GPZDA UTC Time and Date ....................................................................................................171

GPZTG UTC & Time to Destination Waypoint.......................................................................172

MKPA/B Mark Position........................... ......................... .......................... ......................... ..... 173

MKTA/B Time of Mark Input............................................... ............................................... ..... 174

NAVA/B Waypoint Navigation Data............................. ... .......................... ... .......................... .175

PAVA/B Position Averaging Status.......................................................................................... 178

POSA/B Computed Position..................................................................................................... 180

PRTKA/B Computed Position RTK ................... .......................... ......................... ................181

PVAA/B XYZ Position, Velocity and Acceleration...... ... .......................... ... .... .... ...................183

PXYA/B Computed Cartesian Coordinate Position..................................................................185

RALA/B Raw Almanac.............................................................................................................188

RASA/B RAW ALMANAC SET.............................................................................................189

RBTA/B Satellite Broadcast Data: Raw Bits............................................................................ 191

RCCA Receiver Configuration ................................................................................................. 192

RCSA/B Receiver Status..................................... ......................... .......................... ... ................193

REPA/B Raw Ephemeris...................... .... .... ... .......................... ......................... .......................194

RGEA/B/D Channel Range Measurements.............................................................................. 195

RINEX Receiver-Independent Exchange Format..................................................................... 204

RPSA/B Reference Station Position and Health.......................................................................205

RTCA Standard Logs...................................................................................................................206

RTCM Standard Logs ..................................................................................................................206

RTKA/B Computed Position - Time Matched RTK.............................................................. 207

RTKOA/B RTK Solution Parameters RTK ................ ......................... .... ... .......................... .209

RVSA/B Receiver Status...........................................................................................................212

SATA/B Satellite Specific Data................................................................................................214

SBTA/B Satellite Broadcast Data: Raw Symbols.....................................................................216

SPHA/B Speed and Direction Over Ground.............................................................................217

SVDA/B SV Position in ECEF XYZ Coordinates with Corrections........................................ 218

TM1A/B Time of 1PPS ............................................................................................................. 220

VERA/B Receiver Hardware and Software Version Numbers.................................................221

VLHA/B Velocity, Latency, and Direction Over Ground ........................................................222

WALA/B WAAS Almanac WAAS.......................................................................................224

WEPA/B WAAS Ephemeris WAAS ............... ... .... .......................... ......................... ............226

WRCA/B Wide Band Range Correction (Grouped Format)............ .... ......................... .... ........ 228

WUTCA/B UTC Time Parameters WAAS............................................................................229

E Comparison Of RT-2 And RT-20 231

E.1 RT-2 & RT-20 Performance.................................................... ... .......................... .............................. 231

RT-2 Performance........................................................................................................................232

RT-20 Performance......................................................................................................................234

E.2 Performance Considerations...............................................................................................................237

Performance Degradation.............................................................................................................237

F Standards and References 239 G Geodetic Datums 240 H Some Common Unit Conversions 242

6 MiLLennium GPSCard SW Version 4.52 Command Descriptions Manual Rev 2

I Information Messages 244

Type 1 Information Messages...................................................................................................................244

!ERRA..........................................................................................................................................244

!MSGA......................................................................................................................................... 244

Type 2 Information Messages...................................................................................................................245

J Listing Of Tables 248 K GPS Glossary of Terms 267 L GPS Glossary of Acronyms 275

MiLLennium GPSCard SW Version 4.52 Command Descriptions Manual Rev 2 7

Tables

1-1 GPSCard Pseudorange Differential Initialization Summary.................................17

1-2 Latency-Induced Extrapolatio n Error................................. ......................... ..........18

2-1 Commands By Function .......................................................................................26

2-2 GPSCard Command Summary................................ ... .... .......................... .............28

3-1 Logs By Function ............... ... .... ......................... .......................... ........................39

3-2 GPSCard Log Summary............................... .... ... .......................... ........................42

4-1 Positioning Modes............................................................................ .....................46

C-1 Antenna LNA Power Configuration........................... .... .... ... .......................... ......83

C-2 Default Values of Process Noise Elements...........................................................97

D-1 GPSCard Soluti on Statu s............................................ ...........................................144

D-2 Position Type.............................. ............................................... ......................... ...145

D-3 RTK Status for Position Type 3 (RT-20) .............................................................145

D-4 RTK Status for Position Type 4 (RT-2) ............................................................145

D-5 Receiver Self-Test Status Codes............................................................................198

D-6 Range Record Format (RGED only).....................................................................201

D-7 Channel Trackin g Sta tu s............. ... .... ......................... ...........................................203

D-8 Ambiguity Type s.............................................. ......................... ......................... ...211

D-9 Searcher Statu s......... ... .......................... ......................... .......................................211

D-10 RTK Status ...................... .... ... .... ............................................... ......................... ...211

D-11 GPSCard Range Reject Codes...................... ......................... .......................... ......215

D-12 GPSCard Velocity Status........ .......................... ......................... ......................... ...223

D-13 Health and Status Bits............................................................................................225

D-14 Data ID Type (Service Provider)...........................................................................225

D-15 UTC Standard Identifier........................... .......................... ......................... ..........230

E-1 Comparison of RT-2 and RT-20............................................................................231

E-2 RTK Messages Vs. Accuracy.................................. ... .......................... .................231

E-3 RT-2 Performance: Static Mode............................................................................232

E-4 RT-2 Performance: Kinematic Mode....................................................................232

E-5 RT-2 Degradation With Respect To Data Delay ¿................................................232

E-6 RT-20 Performance..... .... .... ......................... ......................... .......................... ......235

G-1 Reference Ellips o id Con sta nts...................... .... ... .......................... ........................240

G-2 Transformatio n Pa rame te rs (Loc al Geod et ic to WGS8 4).....................................240

I-1 Type 1 !ERRA Types .................... .......................... ......................... .....................244

I-2 Type 1 !MSGA Types ........................... ......................... .......................... .............245

MiLLennium GPSCard SW Version 4.503/4.52 Command Descriptions Manual Rev 2 8

Figures

2-1 The WAAS Concept..............................................................................................30

3-1 Pass-Through Log Data.........................................................................................44

A-1 NAVSTAR Satellite Orbit Arrangement........................ .... ......................... .... ... ...63

A-2 Illustration of G PSCa rd Heigh t Me asu reme n ts.....................................................65

A-3 Accuracy versus Pre ci sion..................... ... .......................... ......................... ..........66

A-4 Example of Differential Positioning......................................................................67

A-5 Single Point Averaging..........................................................................................71

A-6 Typical Differentia l Con figu ra tio n................................. .... ... .... ......................... ...72

B-1 Illustration of GPS Signal Multipath............................................................... ......75

B-2 Illustration of GPS Signal Multipath vs. Increas e d Ante nn a Heigh t............... ... ...77

B-3 Illustration of Quadrifilar vs. Microstrip Patch Antennae..................................... 78

B-4 Comparison of Multipath Envelopes.....................................................................80

C-1 HELP Command Screen Display..........................................................................104

C-2 Appended Command Screen Display............................. .......................... .............104

C-3 Illustration of Magnetic Variation & Correction.............................. .... .................109

C-4 Using SEND Command..................... .... ... .......................... ......................... ..........123

C-5 Illustration of SETNAV Parameters.................... .... ... .... .......................... ... .... ......129

C-6 Illustration of Undulation.............................................................. ........................132

D-1 Example of Navigation Parameters.......................................................................177

D-2 The WGS84 ECEF Coordinate System.................................................................187

E-1 Typical RT-2 Horizontal Convergence - Static Mode...........................................233

E-2 Typical RT-2 Horizontal Convergence - Kinematic Mode...................................233

E-3 RT-2 Accuracy Convergenc e............................................................... .................234

E-4 Illustration of RT-2 Steady State Perfor man ce.............................. ........................234

E-5 Typical RT-20 Convergence - Static Mode............. ... .... .... ......................... ..........235

E-6 Typical RT-20 Convergence - Kinema tic Mode....................... .... ........................236

E-7 RT-20 Steady State Performance ..........................................................................236

E-8 RT-20 Re-initialization Process.............................................................................238

MiLLennium GPSCard SW Version 4.503/4.52 Command Descriptions Manual Rev 2 9

Software License

SOFTWARE LICENSE

BY OPENING THE SEALED DISK PACKAGE YOU ARE AGREEING TO BE BOUND BY THE TERMS OF THIS AGREEMENT. IF YOU DO NOT AGREE TO THE TERMS OF THIS AGREEMENT PROMPTLY RETURN THE UNOPENED DISK PACKAGE AND THE ACCOMPANYING ITEMS TO NOVATEL INC.

1. License: NovAtel Inc. (“NovAtel”) grants you a non-exclusive license (not a sale) to use one copy of the enclosed NovAtel software on a single computer, and only with the product whose model number and serial number appear on the en velope.

2. Copyright: NovAt el owns, or has the right to sub license, a ll copy right, tra de secret, p atent an d other p ropriet ary righ ts in the software and the software is protected by national copyright laws, international treaty provisions and all other applicable national laws. You must treat the software like any other copyrighted material except that you may either (a) make one copy of the software solely for ba ckup or archiv al pur poses , or (b) tran sfer t he softwar e to a single hard disk pr ovi ded yo u kee p the original solely for backup or a rc hi val p urp ose s. Yo u ma y not c op y the p r od uct m a nu al o r written mate ria ls a cco mpa n yin g the software.

3. Restrictions: You may not: (1) copy (other than as provided for in paragraph 2), distribute, rent, lease or sublicense all or any portion of the software; (2) modify or prepare derivative works of the software; (3) use the software in connection with computer-based services business or public ly display visual ou tput of the software ; (4) transmit the soft ware over a network, by telephone or elec tronical ly using any me ans; or (5) r everse eng ineer, deco mpile or dis assemble the software . You agree to ke ep confidential and use your best efforts to prevent and protect the conten t s of th e soft ware from unauthorized disclosure or us e.

4. Term and Termination: This Agreement is effective until terminated. You may terminate it at any time by destroying the software, including all computer programs and documentation, and erasing any copies residing on computer equipment. If you do so, you should inform NovAtel in writing immediately. This Agreement also will terminate if you do not comply with any of its terms or conditions. Upo n such termination you are obligate d to destroy the softwa re and erase all cop ies residing on computer equipment. NovAtel reserves the right to terminate this Agreement for reason of misuse or abuse of this software.

5. Warranty: For 90 days from the date of shipment, NovAtel warrants that the media (for example, diskette) on which the software is contained will be free from de fe cts in ma te rials and work man ship . Th is wa rranty do e s no t c over dam age cau sed by improper use or neglect. NovAtel does not warrant the contents of the software or that it will be error free. The software is furnished "AS IS" and without warranty as to the performance or results you may obtain by using the software. The entire risk as to the results and performance of the software is assumed by you.

6. For software UPDATES and UPGRADES, and regular customer support, contact the NovAtel GPS Hotline at

1-800-NOVATEL (Canada and the U.S.A. only), or directly for International Customers 1-403-295-4900, Fax 1-403-2954901, e-mail to support@novatel.ca, visit out world wide web site at http://www.novatel.ca, or write to:

NovAtel Inc. Customer Service Dept. 1120 - 68th Avenue NE Calgary, Alberta, Canada T2E 8S5

7. Disclaimer of Warranty and Limitation of Liability: a. THE WARRANTIES IN THIS AGREEMENT REPLACE ALL OTHER WARRANTIES, EXPRESS OR

IMPLIED, INCLUDING ANY WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. NOVATEL DISCLAIMS AND EXCLUDES ALL OTHER WARRANTIES. IN NO EVENT WILL NOVATEL'S LIABILITY OF ANY KIND INCLUDE ANY SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES, INCLUDING LOST PROFITS, EVEN IF NOVATEL HAS KNOWLEDGE OF THE POTENTIAL LOSS OR DAMAGE.

b. NovAtel will not be liable for any loss or damag e caused by delay in fur nishing the software or a ny other performan ce

under this Agreement.

c. NovAtel's entire liability a nd your e xclusive remedie s for our liab ility of any kind (inc luding li abilit y for negli gence)

for the software covered by this Agreement and all other performance o r non performance by NovAtel un der or related to this Agreement are limited to the remedies specified by this Agreement.

This Agreement is governe d by the laws of the Provinc e of Alberta, Canada. Each of the parties hereto irrevocably attorns to the jurisdiction of the courts of the Province of Alberta.

10 MiLLennium GPSCard SW Version 4.503/4.52 Command Descriptions Manual Rev 2

Software Support

SOFTWARE SUPPORT

Software updates are software revisions to an existing model which improves (but does not increase) basic functionality of the GPS receiver. During the one year warranty coverage following initial purchase, software updates are supplied free of charge. After the warranty has expi red, software up dates and updated manuals may be subject to a nominal charge.

Software upgrades are software releases which increase basic functionality of the receiver from one model to a higher level model type. When available, upgrades can be pu rchased at a pr ice which is the d ifference between the two model types on the current NovAtel GPS Price List plus a nominal service charge.

Software updates and upgrades are obtained through NovAtel authorized dealers or NovAtel Customer Support. Contact your local NovAtel dealer for more information. To locate a dealer in your area, contact NovAtel in any of the following ways:

• GPS Hotline at 1-800-NOVATEL (1-800-668-2835)

(U.S.A. and Canada only; 8 a.m. - 4:30 p.m. Mountain Standard Time)

• telephone: 1-403-295-4900 (8 a.m. - 4:30 p.m. Mountain Standa rd Time)

• fax: 1-403-295-4901

• e-mail: support@novatel.ca

• web site: http://www.novatel.ca

• postal address:

NovAtel Inc. Customer Service Dept. 1120 - 68th Avenue NE Calgary, Alberta Canada T2E 8S5

11 MiLLennium GPSCard SW 4.503/4.52 Command Descriptions Manual Rev 2

Foreword

FOREWORD

Congratulations!

Thank you for purchasing a NovAtel GPSCard product. Whether you have bought a stand alone GPSCard or a packaged receiver you will have also received companion

documents to this manual. They will help you get the hardware operational. Afterwards, this text will be your primary MiLLennium GPSCard command and logging reference source.

Scope

The MiLLennium Command Descriptions Manual describes each command and log that the MiLLennium GPSCard is capable of accepting or outputting. Sufficient detail is provided so that you can understand the purpose, syntax, and structure of each command or log and be able to effectively communicate with the GPSCard, thus enabling the developer to effectively use and write custom interfacing softwar e for specific n eeds and applications . The manual is organized into chapters which allow easy access to appropriate information about the GPSCard.

This manual does not address in detail any of the GPSC ard hardware attributes or installation information. Please consult the appropriate companion manual for hardware or system technical specifications information. Furthermore, should you encounter any functional, operational, or interfacing difficulties with the GPSCard, consult the appropriate hardware manual for NovAtel warranty and customer support information.

Prerequisites

As this reference manual is focused on the GPSCard commands and logging protocol, it is necessary to ensure that the GPSCard has been properly installed and powered up according to the instructions outlined in the companion hardware manual before proceeding.

To use your NovAtel GPS receiver effectively, you should be familiar with the Global Positioning System (GPS) as it applies to positioning, navigation, and surveying applications. For your reference Appendix A of this manual provides an overview of the Global Positioning System.

This manual covers the full performance capabilities of all MiLLennium GPSCards. Every MiLLenn ium can be upgraded through a family of firmware models, each having unique features. Ther efore, depending on the software configuration of your MiLLennium, certain commands and logs may not be accessible. Feature-tagging symbols have been created to help clarify which commands and logs are only available with a certain option:

RTK Features available only with MiLLennium GPSCards equipped with the RT-20 or RT-2 option WAAS Features available only on MiLLennium GP SCard s equipped with the WAAS/EGNOS option

What’s New In This Manual?

This manual includes enhancements that apply to both Firmware 4.503 and 4.52 (Points #1 and #2 below). Points #3 to #6 are enhancements that apply only to Firmware 4.52.

1. Further WAAS/EGNOS capabilities with the additions to the WAASCORRECTION and IONOMODEL

commands.

2. New WEPA/B and WUTCA/B logs.

3. Aircraft & Rapid Kinematic Applicatio n Optimization. Enhanced satellite tracking ability unde r demanding

high velocity and rapidly changing altitude circumstances, especially applications involving aircraft and photogrammetry.

4. Improvements to L1 / L2 AGC Po wer Calculations. MiLLen nium GPS Cards are now bet ter equipped to handle

increased ionospheric activity and atmospheric disturbances caused by the increasing solar activity of the approaching solar maximus.

5. Fixed TM1 log to correctly display the week field.

6. Decreased Sensitivity to RF Interference and Jamming. MiLLennium GPS Cards will now more accurately

track L1 and L2 GPS signals through high levels of external RF interference. Examples of RF interference sources include intentional or accidental RF jamming and increased solar activity.

12 MiLLennium GPSCard SW Version 4.503/4.52 Command Descriptions Manual Rev 2

1 Quick Start

1 QUICK START

This chapter will help you get started quickly regardless of whether you wish to carry out real-time kinematic (RTK) positioning, operate in differential modes or simply log data. Each section references additional sources of information.

1.1 INSTALLATION

For more detailed instructions on the installation and set up of your GPSCard please refer to the accompanying MiLLennium GPSCard Guide to Installation and Operation.

The MiLLennium receiver is designed for flexibility of integration and configuration. You are free to select an appropriate data and signal interface, power supply system and mounting structure. This concept allows OEM purchasers to custom-design their own GPS-based positioning system around the MiLLennium GPSCard.

Installing the MiLLennium GPSCard typically consists of the followin g:

• Mount the GPSCard in a secure enclosure to reduce environmental exposure, RF interference and vibration effects

• Pre-wire the I/O harness and the 64-pin DIN female connector for power and communications, then connecting them to the OEM series GPSCard

• Install the GPSAntenna, then connect to the GPSCard

• (Optional) Install an external oscillator if additional precision and stability is required

OPERATION

Once the hardware and software installations ha ve been completed, you are now read y to beg in initial operation of the GPSCard receiver.

Communication with the MiLLennium GPSCard consists of issuing commands through the COM1 or COM2 port from an external serial communications device. This could be either a terminal or an IBM-compatible PC that is directly connected to a MiLLennium GPSCard COM port using a null modem cable.

TURNING ON

The initial operating software and firmware of th e MiLLennium GPSCard resides in its read-only m emory. As such, the unit “self-boots” upon power- up. The green LED indicato r should b link ab out once per secon d if t he unit is operating normally. The red one lights up if an error is detected during a self-test. The self-test status word can be viewed in the RGEA/B/D and RVSA/B data output logs.

If a persistent error develops please con tact the Nov Atel GPS Customer Service Departm ent fo r fu rther assistance

COMMUNICATION DEFAULT SETTINGS

COM1 and COM2 for the MiLLennium GPSCards are defaulted to the following RS232 protocol:

• 9600 bps, no parity, 8 data bits, 1stop bit, no handshake, echo off

Graphical Interface

Your GPSCard comes with a disk containing NovAtel’s graphical interface software GPSolution, a Microsoft Windows-based program , enabling you to us e your GP SCard w ithout s truggl ing wit h commun ications protoc ol or writing make-do software.

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The View menu options allow you to select or de-select various visual aids and display screens. Take a look at all of the options and keep open those you wish to display. To send commands and log data the Command Console screen should be visible. ASCII format logs can be monitored on the ASCII Record screen.

e.g. On the command line of the Command Console screen type: After you hit the <Enter> key the ASCII Record screen will display the output for your current position. The

POSA/B log is described on Page 180.

log com1 posa once

1.2 DATA LOGGING

The GPSCard has four major logging formats:

• NovAtel Format Data Logs (ASCII/Binary)

• NMEA Standard Format Data Logs (ASCII)

• RTCM Standard Format Data Logs (Binary)

• RTCA Standard Format Data Logs (Binary)

All data types can be logged using several methods of triggering each log event. Each log is initiated using the LOG command. The LOG command and syntax are listed following.

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Syntax: log [port],datatype,[trigger],[period],[offset],{hold}

Syntax Description Example

LOG LOG port COM1 or COM2 Defaults to the port that the command was entered on. COM1 datatype Enter one of the valid ASCII or Binary Data Logs (see Chapter 4, Page 35 and Appendix D, Page 138) POSA trigger Enter one of the following triggers. ONTIME

ONCE Immediately logs the selected data to the selected port once. Default if trigger field is left

ONMARK Logs the selected data when a MARKIN electrical event is detected. Outputs internal buffers

ONNEW Logs the selected data each time the data is new even if the data is unchanged. ONCHANGED Logs the selected data only when the data has changed.

ONTIME

[period], [offset]

CONTINUOUSLY Will log the data all the time. The GPSCard will generate a new log when the output buffer

period Use only with the ONTIME trigger. Units for this parameter are seconds. The selected period may be any of the

following values: 0.05, 0.10, 0.20, 0.25, 0.50, 1, 2, 3, ... , 3600 seconds but may be limited by the GPSCard model and previously requested logs. Selected data is logged immediately and then periodic logging of the data will start at the next even multiple of the period. If a period of 0.20 sec is chosen, then data will be logged when the receiver time is at the 0.20, 0.40, 0.60 and the next (0.80) second marks. If the period is 15 seconds, then the logger will log the data when the receiver time is at even 1/4 minute marks. The same rule applies even if the chosen period is not divisible into its next second or minute marks. If a period of 7 seconds is chosen, then the logger will log at the multiples of 7 seconds less than 60, that is, 7, 14, 21, 28, 35, 42, 49, 56 and every 7 seconds thereafter.

offset Use only with the ONTIME trigger. Units for this parameter are seconds. It provides the ability to offset the logging

events from the above startup rule. If you wished to log data at 1 second after every minute you would set the period to 60 seconds and the offset to 1 second (Default is 0).

hold Will prevent a log from being removed when the UNLOGALL command is issued HOLD

blank.

at time of mark - does not extrapolate to mark time. Use MKPA/B for extrapolated position at time of mark.

Immediately logs the selected data and then periodically logs the selected data at a frequency determined by the period and offset parameters. The logging will continue until an UNLOG command pertaining to the selected data item is received (see the UNLOG command, Page 134).

associated with the chosen port becomes empty. The continuously option was designed for use with differential corrections over low bit rate data links. This will provide optimal record generation rates. The next record will not be generated until the last byte of the previous record is loaded into the output buffer of the UART.

NOTE: The syntax for a command can contain option al parameters (OPT1, OP T2, ...). OPT2 may only be us ed if

it is preceded by OPT1. OPT3 may only be used if it is preceded by OPT2 and so on. Parameters after and including OPT1 will be surrounded by square brackets.

An optional parameter such as {hold} surrounded by braces may be used with the log command without any preceding optional parameters.

Example:

log com1 posa 60 1 hold log com1 posa hold

Example:

log com1,posa,ontime,60,1

If the LOG syntax does not include a trigger type, it will be output only once following execution of the LOG command. If trigger type is specified in the LOG syntax, the log will continu e to be output based on the trigger specification. Specific logs can be disabled using the UNLOG command, whereas all enabled logs will be disabled by using the UNLOGALL command (see Chapter 2, Page 24 and Appendix C, Page 81). All activated logs will be listed in the receiver configuration status log (RCCA), Page 192.

The [port] parameter is optional. If [port] is not specified, [port] is defaulted to the port that the command was received on.

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COMMONLY USED LOGS

Type Logs Trigger

Positioning PRTKA/B

POSA/B

Post Processing RGEA/B/D

REPA/B, ALMA/B

NMEA Position GPGLL

GPGGA

Other useful logs are

• RCCA to list the default command settings

• ETSA to monitor the channel tracking status

• SATA to obser ve the satellite specific data

• DOPA to monitor the dilution of precision of the current satellite constellation

• RVSA to monitor the receiver status

For further information on output logging see Chapter 4, Page 35 and the individual logs listed alphabetically in Appendix D, Page 138.

Use the HELP command to list all available commands. For more info rmation on sending comm ands s ee Chapter 2, Page 24 and the individual commands listed alphabetically in Appendix C, Page 81.

ontime or onmark

ontime onchanged

ontime or onmark

1.3 DIFFERENTIAL OPERATION

The MiLLennium GPSCard is ideal for design into DGPS systems because it is capable of operating as either a reference station or a rover station.

The GPSCard is capable of utilizing various formats of differential corrections. These formats are divided into two primary groups RTCM and RTCA.

For detailed data structure concerning these logs, please see:

Chapter 3, Page 35 Chapter 4, Page 46 Appendix D, Page 138

Establish a Data Link

Operating the GPSCard with a DGPS system requires that the reference station broadcast differential correction data messages to one or more rover receivers. As there are many methods by which this can be achieved, it is up to you to establish an appropriate data link that best suits your user requirements.

Whatever data link is chosen, the operator of the reference station will want to ensure that the bit rate of data transmission is suitable for the an ticipated data lin k and remote u sers. Use the GPS Card COMn comm and to the COM port default bit rate (default is 9600 bps, no parity, 8 data bits, 1 stop bit, no handshake, echo off).

Note that the GPSCard COMn_DTR and COMn_RTS commands are available for remote device keying (such as a radio transmitter). These commands allow for flexible control of the DTR and RTS lines to be precisely timed with log transmissions.

Further information may be found in Appendix A. Table 1-1, following, is a GPSCard pseudorange differential initialization summary.

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Required:

Table 1-1 GPSCard Pseudorange Differential Initialization Summary

Reference Station Remote Station

FIX POSITION lat lon hgt id (health) LOG port DATATYPE ontime 5

Required:

ACCEPT port DATATYPE

1 Quick Start

Recommended Options:

LOG DATATYPES (binary):

LOG DATATYPE S (asc ii):

RTCMB RTCAB RTCM RTCA

RTCMA RTCAA

Related Commands/Logs:

RTCMRULE DATUM

Example 1:

fix position 51.3455323 -114.2895345 1201.123 555 0 log com 1 RTCM ontime 2

Example 2:

fix position 51.3455323 -114.2895345 1201.123 555 0 log com2 rtcaa ontime 2

Note: Italicized entries indicate user definable.

Recommended Options:

ACCEPT DATATYPES (binary):

ACCEPT COMMANDS (ascii):

Related Commands/Logs:

RTCMRULE DATUM

POSA/B VLHA/B CDSA/B GPGGA

Example 1:

accept com2 rtcm log com1 posa ontime 1

Example 2:

accept com2 commands log com1 posa ontime 0.2 log com1 vlha ontime 0.2

RTCM RTCA

RTCMA RTCAA

Initialization - Reference Station

Differential mode of operation is established at the reference station through a two step process: fix position and logging observation and correction data.

FIX POSITION

The reference station must initialize the precise position of its reference antenna phase centre (lat/lon/hgt). This is accomplished by utilizing the GPSCard FIX POSITION command. The syntax is as follows:

Syntax:

FIX POSITION lat lon height station id health

Example:

fix position 51.3455323,-114.2895345,1201.123,555,0

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NOTE 1: Entry of the station ID and health are optional. For a CMR correction type the station ID mu st b e < 31 . NOTE 2: The accuracy of the reference station’s FIX POSITION setting will directly affect the accuracy of its

computed differential corrections. Good results at the rover station are dependent on the reference station’s combined position errors being kept to a minimum (e.g., fix position error + multipath errors).

NOTE 3: The GPSCard performs all computations based on WGS84 and is defaulted as such, regardless of

DATUM command setting. The datum in which you choose to operate is converted from WGS84; therefore, all differential corrections are based on WGS84. Ensure that any change in your operating datum is set prior to FIX POSITION.

NOTE 4: When transmitting RTCM type data, the GPSCard has various options for assigning the number of data

bits per byte. Please see the GPSCard command RTCMRULE, Page 116 for further information concerning RTCM data bit rule settings.

NOTE 5: The FIX POSITION “health” field entered will be reported in word 2 of the RTCM message frame

header.

Once the GPSCard has its position data fixed and is tracking th ree or more satellites, it is now ready to trans mit differential correction and observation data to the rover stations.

LOG BROADCAST DATA

Assuming that a data link has been establi shed, use the GPSCard log command to send observation and di fferential corrections data for broadcast to the rover stations.

Syntax:

LOG port data ontime seconds

Example:

log com1 rtcm ontime 5

NOTE: Ensure that the bit rate of the data link is suitable for the differential type, logging rate and maximum

message length of the data type being logged.

1.4 RTK MODE

NovAtel’s RTK system utilizes proprietary messaging as well as RTCM Types 18 and 19, and can also receive CMR messages from a non-NovAtel base station. For more information on specific message formats please see Chapter 4, Page 46.

NOTE: No guarantee is made that the MiLLennium will meet its performance specifications if non-NovAtel

accessories (e.g. antennas, RF cable) are used.

Data Communications Link

It is the user’s responsibility to provide a data communicatio ns link between the reference station and remote station. The data transfer rate must be high enough to ensure that sufficient reference station messages reach the remote station to keep extrapolation errors from growing too large; see Table 1-2.

Table 1-2 Latency-Induced Extrapolation Error

Time since last reference station observation Typical extrapolation error (CEP)

0-2 seconds 1 cm/sec 2-7 seconds 2 cm/sec 7-30 seconds 5 cm/sec

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Generally, a communications link capable of data throughput at a rate of 4800 bits per second or higher is sufficient. However, it is possible to satisfactorily use a lower rate (e.g. 2400 bps) with the RTC A, RTCM 59 and CMR formats. RTCM Types 18 and 19 may require a higher rate; see Chapter 4, Message Formats, Page 46 for additional information. The minimum data transfer rate is based on the following :

1. RT-2 requires th at the reference station periodically transmit two RTCA Standard Type 7 messages:

• An RTCAOBS message contains reference station satellite observation information, and

should be se nt once every 1 or 2 seconds.

• An RTCAREF message contains reference station position information, and should be

sent once every 10 seconds.

OR periodically transmit an R TCM Type 18 and RTCM Type 19 (R TCM1819) me ssage together with an

RTCM Type 3 message:

• A Type 3 message contains reference station position information , and shou ld be sent

once every 10 seconds (although it is possible to send it as infrequently as once every 30 seconds).

• RTCM1819 gives raw measurement information (Type 18 provides carrier phase

measurements, while Type 19 provides pseudorange measurements) and should be sent once every 1 or 2 seconds.

NOTE: This message can be sent in RT CM Version 2. 1 or Vers ion 2.2 fo rmat, contro lled with the RTKMODE

command.

and, optionally, also periodically transmit an RTCM Type 22 message together with an RTCM Type 3 message:

• A Type 3 message contains reference station position information , and shou ld be sent

once every 10 seconds (although it is possible to send it as infrequently as once every 30 seconds).

• A Type 22 message gives extended reference station parameters and should be sent once

every 10 seconds.

OR periodically transmit two CMR messages where the station ID, see Page 100, must be

transmitting CMR corrections:

• A CMROBS message contains reference station satellite observation information, and

should be se nt once every 1 or 2 seconds.

• A CMRREF message contains reference station position information, and should be sent

once every 10 seconds.

2. RT-20 requires that the reference station periodically transmit either the RTCA messages listed above (the recommended option), or RTCM 1819 or CMR messages or the RTCM SC-104 Type 3 & 59N messages:

• A Type 3 message contains reference station position information , and shou ld be sent once every 10 seconds (although it is possible to send it as infrequently as once every 30 seconds).

• A Type 59N message contains reference station satellite observ ation information, and should be sent once every 2 seconds.

≤ 31 when

Further information on RTCA, RTCM and CMR message formats is contained in Chapter 6.

System Initiali za t ion

The RTK system is designed for ease of use: you set up the remote station, enter a command so that it accepts RT2 or RT-20 messages from the reference station, and are ready to go. There are options, however, which can be used to adapt the system to a specific application. Some options apply only to the reference station, while others

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apply only to the remote station. Detailed descriptions can be found in Appendix C, Commands Summary. In the following sections, keep the following in mind:

• Dynamics modes. For reliable performance the antenna should not move more than 1-2 cm when in static mode. See the RTKMODE commands in Chapter 2, Page 24 and Appendix C, Page 117 for more information.

• When using the FIX POSITION command, the height entered must be in metres above mean sea level; it will be converted to ellipsoidal height inside the receiver. You can enter an undulation value, if desired, using the UNDULATION command; if none is entered, the receiver estimates an undulation with its internal table. The format of the optional station ID field depends on whether RTCM or R TC A mes sages ar e being us ed: if RTCM, any number from 0 - 1023 is valid, while if RTCA, any 4-character string of numbers and upper-case letters, enclosed in quotation marks, is valid. See Appendix C, Page 100 for additional information on the station id field.

• The COMn field refers to the se rial por t (eit her COM1 or COM2) to which data communications equipment is connected. The serial port assignment at the reference and remote stations need not be the same; e.g. a radio transmitter might be connected to COM1 at the reference station, and a radio receiver to COM2 at the remote station.

INITIALIZATION FOR RTCA-FORMAT MESSAGING (RT-2 OR RT-20)

The following commands will enable RTCA-format messaging and allow RT-2 or RT-20 to operate with the remote station either at rest or in motion. Note that the optional station health field in the existing FIX POSITION command is not currently implemented in NovAtel’s RTCA messages, though it will be in the future.

1. At the reference station:

fix position lat,lon,height,station id log comn,rtcaref,ontime,interval log comn,rtcaobs,ontime,interval

Example:

fix position 51.11358042,-114.04358013,1059.4105,”RW34” log com1,rtcaref,ontime,10 log com1,rtcaobs,ontime,2

2. At the remote station:

accept comn,rtca

Example:

accept com2,rtca

Congratulations! Your RTK system is now in operation!

INITIALIZATION FOR RTCM59-FORMAT MESSAGING (RT-20 ONLY)

Although RT-20 can operate with either RTCA or RTCM-format messaging, the use of RTCA-format messages is recommended (see Chapter 4, Page 46 for further information on this topic). Nevertheless, the following commands will enable RTCM59-format messaging and allow RT-20 to operate with the remote station either at rest or in motion:

1. At the reference station:

fix position lat,lon,height,station id,station health log comn,rtcm3,ontime,interval log comn,rtcm59,ontime,interval

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Example:

fix position 51.11358042,-114.04358013,1059.4105,119,0 log com1,rtcm3,ontime,10 log com1,rtcm59,ontime,2

2. At the remote station:

accept comn,rtcm

Example:

accept com2,rtcm

Congratulations! Your RT-20 system is now in operation!

Monitoring Your RTK Output Data

At the remote station, you could now select any or all of these output logs for positioning information:

• BSLA/B Baseline Measurement

• NMEA-format logs

• POSA/B Computed Position

• PRTKA/B Best Position

• RPSA/B Reference Station Position & Health

• RTKA/B RTK Output - Time Matched Positions

The POSA/B, PRTKA/B and NMEA-format logs contain the low-latency position; the RTKA/B logs co ntain the matched position. The low-latency solution is the recommended one for kinematic users, while the matched

solution is the one recommended for stationary users. Fo r a discussion on low-latency and matched positions, see the Differential Positioning section of Appendix A, Page 67.

Options for Logging Differential Corrections

SET DGPSTIMEOUT

The DGPSTIMEOUT command allows the reference station to set the delay by which it wil l inhibit utilization of new ephemeris data in its differential corrections. This delay ensures that the remote receivers have had sufficient time to collect updated ephemeris data as well.

A delay of 120 to 130 seconds will typically ensure that the rover stations have collected updated ephemeris. After the delay period is pas sed, t he r eferen ce st at ion wi ll b egi n us ing n e w ephem eri s dat a. To ent er an ephemeris delay value, you must first enter a numeric placeholder in the DGPS delay field (e.g., 2). When operating as a reference station, DGPS delay will be ignored (see the DGPSTIMEOUT command found in Chapter 2, Page 24 and Appendix C, Page 92 for further information on using this command at rover stations.)

Syntax:

DGPSTIMEOUT dgps delay ephem delay

Command Option Description Default

DGPSTIMEOUT Command dgps delay min. 2

max. 1000

ephem delay min. 0

max. 600

Maximum age in seconds 60

Minimum time delay in seconds 120

Example:

dgpstimeout 2,300

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USING RTCM SC-104 LOG TYPES

RTCM SC-104 is a standard for transmitting differential corrections between equipment from different manufacturers. The NovAtel GPSCard is capable of transmitting or receiving RTCM data.

To facilitate transmitting the RTCM data over shared data links, the GPSCard is also capable of sending the RTCM log in NovAtel ASCII format (R TCMA) or with the NovA tel binary header (R TCMB) added to allow s ynchronous transmission and reception along with other data types.

NOTE: When sending or receiving RTCM log types, it is important to ensure that all connected equipment are

using the same RTCMRULE for compatibility.

The easiest method to send RTCM standard lo gs is from the COM1 o r COM2 ports of the referen ce GPSCard. The easiest method to receive the RTCM data is through the COM1 or COM2 port of the rover GPSCard. The rover GPSCard must issue the “ACCEPT port RTCM” command to dedicate a port before it will accept the RTCM data into that port.

The RTCMA log can be intermix ed with othe r NovAtel A SCII data over a common communication port. It will be directly interpreted by a rover GPSCard as a special data input command ($RTCM). “ACCEPT port COMMANDS” must be used with this input command. A non-NovAtel rover station will need to strip off the header ($RTCM) and terminator (*xx), then con vert the hexadecimal data to binary befo re the RTCM standard data can be retrieved.

The RTCMB log can be intermixed with other NovAtel binary data over a common communication port.

REMEMBER: Use the CDSA/B logs to monitor the COM port activity, success, and decoding errors.

USING RTCA LOG TYPES

The RTCA (Radio Technical Commission for Aviation Services) Standard is being designed to support Differential Global Navigation Satellite System (DGNSS) aviation applications. The perceived advantage to using RTCA type messages for transmitting and receiving differential corrections versus using RTCM type messages is that RTCM transmits 30-bit words, and the data is difficult to decode and process because of the parity algorithm and irregular word sizes used. RTCA is transmitted in 8-bit words, which are easier to generate, process and decode. The RTCA messages are therefore smaller, they have a 24 bit CRC that is much more robust than RTCM messages, and they permit the use of a four-alpha-character station ID.

RTCA standard logs can be received through the COM1 or COM2 port of the rover GPSCard. The remote GPSCard must issue the “ACCEPT port RTCA” command to dedicate a port before it will accept the RTCA data input to that port. The RTCA logs cannot be intermixed with other logs.

The RTCAA log can be intermixed with other NovAtel ASCII data over a common communications port. It will be directly interpreted by a rover GPSCard as a special data input comman d ($RTCA). “ACCEPT po rt commands” must be used with this input command. A non-NovAtel rover station will need to strip off the header ($RTCA) and terminator (*xx), then convert the hexadecimal data to binary before the RTCA standard can be retrieved.

The RTCAB log can be intermixed with other NovAtel binary data. Th e remote GPSCard identifies the RTCAB log by the message block identifier contained in the message, and will interpret only the RTCA data portion of the log.

NOTE: The CDSA/B logs may be used to monitor the COM port activity and differential data decode success.

Initialization - Rover Station

It is necessary to initialize the rover receiver to accept observation data from the reference station. If the receiver is not correctly initialized, it will proceed to compute solutions in single point positioning mode.

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Before initializing, ensure that the data link with the reference station has been properly set up. As well, ensure that the COM port which is to receive the differential data is s et up to match th e bit rate and pr otocol settings of the reference station broadcast data.

Establishing differential mode of operation at the rov er receiver is primarily a one- step process whereb y the accept command is used to enable reception of observation data from the reference station.

ACCEPT COMMAND

The accept command is primarily used to set the GPSCard’s COM port command interpreter for acceptance of various data formats (see the ACCEPT command in Chapter 2, Page 24 and Appendix C, Page 81).

Syntax

ACCEPT port mode

Example:

accept com2 rtcm

Once intitialized, the rover GPSCard receiver will operate in single point mode until the differential messages are received. If the data messages are lost, the GPSCard will revert to single point positioning until the pseudorange correction messages are restored.

NOTE: Ensure that the GPSCard RTCMRULE settings agree with the bit rule being transmitted by the RTCM

Range Value Default

reference station. Unless otherwise set, all GPSCards default to 6CR.

LOG POSITION DATA AND OTHER USEFUL DATA

The GPSCard remote receiver has many options for information data logging. To monitor position status, the user may find the PRTKA/B logs to be the most informative. Other options exist, such as POSA/B and GPGGA. As well, velocity data can be found in the VLHA/B, SPHA/B and GPVTG logs. It is really up to your specific applications as to the full range of logs you require.

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2 COMMAND DESCRIPTIONS

2.1 GENERAL

This section describes all commands accepted by the GPSCard with the exception of the "Special Data Input Commands". They are listed in alphabetical order. For descriptions of output logs using the LOG command, see Chapter 3.

The GPSCard is capable of responding to over 50 different input commands. You will find that once you become familiar with these commands, the GPSCard offers a wide range in operational f lexibility. All commands are accepted through the COM1 and COM2 serial ports. See Table 2-1, Page 26 for a complete command listing.

NOTE: You will find the HELP command a useful tool for inquiring about the various commands available.

The following rules apply when entering commands from a terminal keyboard:

• The commands are not case sensitive (

e.g. e.g.

HELP or help FIX POSITION or fix position

COMMAND or command).

• All commands and required entries can be separated by a space or a comma

(command,variable

OR command variable).

e.g. datum,tokyo e.g. datum tokyo e.g. fix,position,51.3455323,-117.289534,1002 e.g. fix position 51.3455323 -117.289534 1002 e.g. com1,9600,n,8,1,n,off e.g. com1 9600 n 8 1 n off e.g. log,com1,posa,onchanged e.g. log com1 posa unchanged

• At the end of a command or comm and strin g, p res s th e <CR> key. A carriage return is what

the card is looking for and is usually the same as pressing the <Enter> key.

• Most command entries do not provide a response to the entered command. Exceptions to

this statement are the VERSION and HELP commands. Otherwise, successful entry of a command is verified by receipt of the COM port prompt (i.e. COM1> or COM2>).

The syntax for a command can contain optional parameters (OPT1, OPT2, ...). OPT2 may only be used if it is preceded by OPT1. OPT3 may only be used if it is preceded by OPT2 and so on. Parameters after and including OPT1 will be surrounded by square brackets.

An optional parameter such as {hold} surrounded by braces may be used with the log without any preceding optional parameters

Example:

log com1 posa 60 1 hold log com1 posa hold

When the GPSCard is first powered up, or after a FRESET command, all commands will rev ert to the factory default settings. An example is shown below. The SAVECONFIG command can be used to modify the power-on defaults. Use the RCCA log to reference stati on comm a nd and log settings.

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NOTE: All previously stored configurations that were saved to non-volatile memory are erased (including

Saved Config, Saved Almanac, and Channel Config).

Example:

Optional Calculation Of The Checksum

When an input command is followed by an optional checksum, the checksum will be verified before the command is executed. The checksum is the result of the logical exclusive-OR operation on all the bits in the message. So, the checksum of a command with parameters will change if the parameters are modified.

NOTE: The command must be typed in uppercase for the proper checksum to be calculated.

As an example, it may be essential to ensure that a receiver has received and executed the correct command from a host computer. If the checksum were calculated by the sender and attached to the command, the receiver would be able to recognize if errors had been introduced and if so, alert the sender to this with an “Invalid Command CRC” message.

Example:

FIX HEIGHT 4.567[CR][LF] FIX HEIGHT 4.567*66[CR][LF]

Both are acceptable, but only the second one would trigger the verification function.

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2.2 STANDARD COMMAND TABLES

Table 2-1 lists the commands by function while Table 2-2 is an alphabetical listing of commands. Please see Appendix C, Page 81 for a more detailed description of individual commands which are listed alphabetically.

Table 2-1 Commands By Function Table

COMMUNICATIONS, CONTROL AND STATUS

Commands Descriptions

ANTENNAPOWER Power to the low-noise amplifier of an active antenna COMn COMn port configuration control COMn_DTR DTR handshaking control COMn_RTS RTS handshaking control

DIFF_PROTOCOL FREQUENCY_OUT Variable frequency output (programmable ) LOG Logging control MESSAGES Disable error reporting fro m comm an d in terpre te r RINEX Configure the user defined fiel ds in t he file header RTCMRULE Sets up RTCM bit rule RTCM16T Enters an ASCII message SEND Sends ASCII message to COM port SENDHEX Sends non-printable characters

SETL1OFFSET

1 Intended for advanced users of GPS only

Differential Protocol Control

Add an offset to the L1 pseudorange to compensate for signal delays

GENERAL RECEIVER CONTROL AND STATUS

Commands Descriptions

$ALMA Download almanac data file CRESET Reset receiver to factory default DYNAMICS Set correlator tracking bandwidth HELP On-line command help RESET Performs a hardware reset (OEM only) SAVEALMA Saves the latest almana c in NVM SAVECONFIG Sav es current configuration (OEM onl y) $TM1A Injects receiver time of 1PP S VERSION Software/hardware information

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Table 2-1 Commands By Function Table (continued)

POSITION, PARAMETERS, AND SOLUTION FILTERING CONTROL

Commands Descriptions

CSMOOTH DATUM Choose a DATUM na me type ECUTOFF Satellite elevation cut-off for solutions FIX HEIGHT C onstrains to fixed height (2D mode) FIX POSITION Constrains to fixed lat, lon, height FRESET Clears all data which is stored in NVM $IONA Download ion osphe ric correction data

IONOMODEL LOCKOUT Deweights a satellite in solutions

$PVAA RTKMODE Setup the RTK mode UNDULATION Ellipsoid-geoid separation USERDATUM User-customized datum WAASCORRECTION Controls handling of WAAS/EGNOS corrections.

1 Intended for advanced users of GPS only.

Sets amount of carrier smoot hi ng

What ionospheric correction to use (MiLLennium with the WAAS option)

Position, velocity and accel e rat ion in ECEF coordinates

2 Command Descriptions

SATELLITE TRACKING AND CHANNEL CONTROL

Commands Descriptions

$ALMA Download almanac data file ASSIGN Satellite channel assignment CONFIG Switc hes the channel configuratio n of th e G PSCard DYNAMICS Sets correlator tracking band w idth FIX VELOCITY Aids high ve l ocity reacqu i s ition RESETHEALTH Reset PRN health SETHEALTH Overrides broadcast satellite health

WAYPOINT NAVIGATION

Commands Descriptions

MAGVAR Magnetic variation correction SETNAV Waypoint input

DIFFERENTIAL REFERENCE STATION

Commands Descriptions

DGPSTIMEOUT Sets ephemeris del ay FIX POSITION Constrain to fixed (reference) LOG Selects required differential-output log POSAVE Implements position averagi ng for reference station RTCMRULE Selects RTCM bit rule SETDGPSID Set reference station ID

MiLLennium GPSCard SW Version 4.503/4.52 Command Descriptions Manual Rev 2 27

2 Command Descriptions

Table 2-1 Commands By Function Table (continued)

DIFFERENTIAL REMOTE STATION

Commands Descriptions

ACCEPT Accepts RTCM1, RTCA or RTCA B di fferential inputs $ALMA Input almanac data DGPSTIMEOUT Set maximum age of differential data accepted RESET Performs a hardware reset $RTCA RTCA differential correct io n input (ASCII) $RTCM RTCM differential correction in put (A SCII) RTCMRULE Selects RTCM bit rule SETDGPSID Select differential referen ce stat io n ID to rec ei ve

CLOCK INFORMATION, STATUS, AND TIME

Commands Descriptions

CLOCKADJUST Enable clock modelling & 1PPS adjust

DIFF_PROTOCOL EXTERNALCLOCK Sets default parameters of an optional external oscillator EXTERNALCLOCK FREQUENCY Sets clock rate

SETTIMESYNC $UTCA Download UTC data

Differential protocol control

Enable or disable time syn ch ronization

1 Intended for advanced users of GPS only

Table 2-2 GPSCard Command Summary

Command Description Syntax

$ALMA Injects almanac (follows NovAtel ASCII log format) $IONA Injects ionospheric refract ion corrections (follows NovAtel ASCII log format) $PVAA Injects latest computed position, velocity and acceleration (follows NovAtel ASCII log format) $REPA Injects raw GPS ephemeris data (follows NovAtel ASCII log format) $RTCA Injects RTCA format DGPS corrections in ASCII (Type 1) (follows NovAtel ASCII log format) $RTCM Injects RTCM format differential corrections in ASCII (Type 1) (follows NovAtel ASCII log format) $TM1A Injects receiver time of 1 PPS (follows NovAtel ASCII log format) $UTCA Injects UTC information (follows NovAtel ASCII log format) ACCEPT Port input control (set command interpreter) accept port,option ANTENNAPOWER Power to the low-noise amplifier of an active antenna antennapower flag ASSIGN Assign a prn to a channel # assign channel,prn,doppler, search window UNASSIGN Un-assign a channel unassign channel UNASSIGNALL Un-assign all channels unassignall CLOCKADJUST Disable clock steering mechanism clockadjust switch COMn Initialize Serial Port (1 or 2) comn bps,parity,databits,stopbits, handshake,echo COMn_DTR Programmable DTR lead/tail time comn_dtr control,active,lead,tail COMn_RTS Programmable RTS lead/tail time comn_rts control,active,lead,tail CONFIG Switches the channel configuration of the GPSCard config cfgtype CRESET Configuration reset to factory default creset CSMOOTH Sets carr ier smo oth ing csmooth value DATUM Choose a DATUM name type datum option USERDATUM User defined DATUM userdatum semi-major,flattening,dx,dy,dz, rx,ry,rz,

DGPSTIMEOUT Sets maximum age of differential data to be accepted and ephemeris

delay

scale dgpstimeout value value

28 MiLLennium GPSCard SW Version 4.503/4.52 Command Descriptions Manual Rev 2

2 Command Descriptions

DIFF_PROTOCOL Diffe ren tial cor rect ion messa ge enc odi ng and decod ing for

DYNAMICS Set receiver dyna mics dynamics option [user_dynamics] ECUTOFF Set elevation cutoff angle ecutoff angle EXTERNALCLOCK Sets default parameters of an optional external oscillator externalclock option EXTERNALCLOCK

FREQUENCY FIX HEIGHT Sets height for 2D navigation fix height height [auto] FIX POSITION Set antenna coordinates for reference station fix position lat,lon,height [station id] [health] FIX VELOCITY Accepts INS xyz (ECEF) input to aid in high velocity reacquisition of

UNFIX Remove all receiver FIX constraints unfix FREQUENCY_OUT Variable frequency output (programmable) frequency_out n,k FRESET Clears all data which is stored in non-volatile memory freset HELP or ? On-line command help help option or ? option IONOMODEL Influences what ionospheric corrections the card uses ionomodel keyword LOCKOUT Lock out satellite lockout prn UNLOCKOUT Restore satellite unlockout prn UNLOCKOUTALL Restore all satellites unlockoutall LOG Choose data logging type log [port],datatype,[trigger],[period],[offset],{hold} UNLOG Disable a data log unlog [port],data type UNLOGALL Disable all data logs unlogall [port] MAGVAR Set magnetic variation correction magvar value MESSAGES Disable error reporting from command inte rpre ter messages port,option POSAVE Implements position averaging for reference station posave maxtime, maxhorstd, maxverstd RESET Performs a hardware reset (OEM only) reset RINEX Configure the user defined fields in the file headers rinex cfgtype RTCM16T Enter an ASCII text message to be sent out in the RTCM data stream rtcm16t ascii message RTCMRULE Set variations of the RTCM bit rule rtcmrule rule RTKMODE Set up the RTK mode rrtkmode argument, data range SAVEALMA Save the latest almanac in non-volatile memory savealma option SAVECONFIG Save current configuration in non-volatile memory (OEM only) saveconfig SEND Send an ASCII message to any of the communications ports send port ascii-message SENDHEX Sends non-printable characters in hexadecimal pairs sendhex port data SETDGPSID Enter in a reference station ID setdgpsid option SETHEALTH Override PRN health sethealth prn,health RESETHEALTH Reset PRN health resethealth prn RESETHEALTHALL Reset all PRN health resethealthall SETL1OFFSET Add an offset to the L1 pseudorange to compensate for signal delays setL1offset distance SETNAV Set a destination waypoint setnav from lat,from lon,to lat, to lon,track offset, from

SETTIMESYNC Enable or disable ti me synchronization settimesync flag UNDULATION Choose undulation undulation separation VERSION Current software and hardware information version WAASCORRECTION Dictates how the card handles WAAS/EGNOS corrections waascorrection keyword [prn] [mode]

implementation in the GPS card firmware

Sets clock rate external frequency clock rate

SVs

diff_protocol type key or diff_protocol disable or diff_protocol

fix velocity vx,vy,vz

port,to port

MiLLennium GPSCard SW Version 4.503/4.52 Command Descriptions Manual Rev 2 29

2 Command Descriptions

Gro

Integrity data,differential corrections

time control, and statu

PS Satellit

eConstellationIntegrity da

ta,differential

and ranging

C-ban

tio

2.3 WAAS

The Wide Area Augmentation System (WAAS) is a safety-critical system that provides a quality of positioning information previously unavailable. The WAAS improves the accuracy, integrity, and availability of the basic GPS signals. In the future, the wide area of coverage for this system will include the entire United States and some outlying areas. At the time of publication, there are two WAAS satellites over the western Atlantic Ocean and the Pacific (PRN 122 and PRN 134 respectively) and one EGNOS satellite over the eastern Atlantic Ocean (PRN 120). WAAS data is available from any of these satellites and more satellites will b e available in the fu ture.

The primary functions of WAAS include:

• data collection

• determining ionospheric corrections

• determining satellite orbits

• determining satellite clock corrections

• determining satellite integrity

• independent data verification

• WAAS message broadcast and ranging

• system operations & maintenance

As shown in Figure 2-1, the WAAS is made up of a series of Wide Area Reference Stations, Wide Area Master Stations, Ground Uplink Stations and Geostationary Satellites (GEOs). The Wide Area Reference Stations, which are geographically distributed, pick up GPS satellite data and route it to the Wide Area Master Stations where wide area corrections are generated. These corrections are sent to the Ground Uplink Stations which up-link them to the GEOs for re-transmission on the GPS L1 frequency. These GEOs transmit signals which carry accuracy and integrity messages, and which also provide additional ranging signals for added availability, continuity and accuracy. These GEO signals are available over a wide area and can be received and processed by ordinary GPS receivers. GPS user receivers are thus able to receive WAAS data in-band and use not only differential corrections, but also integrity, residual errors and ionospheric information for each monitored satellite.

GPS User

Figure 2-1 The WAAS Concept

Geostationary Satellite (GEO)

Wide-area

Refere nce Sta t ion

(WRS)

L1 & C-band

Wide-area

Refere nce Sta t ion

(WRS)

Wide-area

Master Station

(WMS)

L1 & L2

Wide-area

Reference Sta

(WRS)

orrections,

control

nd Uplink

tation

(GUS)

30 MiLLennium GPSCard SW Version 4.503/4.52 Command Descriptions Manual Rev 2

+ 255 hidden pages

Novatel OM-20000053 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

OM-20000053 REV 2

Table of Contents

Software License

Software Support

Foreword

Congratulations!

Scope

Prerequisites

What’s New In This Manual?

1.1 INSTALLATION

1.2 DATA LOGGING

1.3 DIFFERENTIAL OPERATION

1.4 RTK MODE

2.1 GENERAL

2.2 STANDARD COMMAND TABLES

2.3 WAAS