Z-12 Real-Time Sensor Operation & Reference Manual Ashtech 1170 Kifer Road Sunnyvale, CA USA 94086 Phone and Fax Numbers • Main • Voice: 408-524-1400 • Fax: 408-524-1500 • Sales • US: 800-922-2401 • International: 408-524-1670 • Fax: 408-524-1500 • Europe • Voice: 44-993-883-533 • Fax: 44-993-883-977 • Support • US: 800-229-2400 • International: 408-524-1680 • Fax: 408-524-1500 • BBS • Direct: 408-524-1527 Internet • • support@ashtech.com http://www.ashtech.
Copyright Notice All rights reserved. No part of this publication or the computer program s described in it may be reproduced, translated, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical photocopying, recording, or otherwise, without prior written permission of Ashtech Inc.
Trademarks Z-12 Real-Time Sensor and the Ashtech logo are tradem arks of Ashtech. All other product and brand names are trademarks or registered trademarks of their respective holders. User Notice FCC (CFR 47, Part 15.105), BS EN 55022: 1995 This equipment has been tested and found to comply with the limits for a Class A digital device, pursuant to FCC, CFR 47, Part 15 Rules, and Class A ITE (Inform ation Technology Equipment), pursuant to the European Standard EN 55022: 1995.
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Table of Contents Chapter 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Chapter 2. Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Equipment Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Antenna . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Sensor . . . . . . . . . . . .
CPD with DBEN message . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Base Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rover/Remote Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RTCM Differential Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . CPD with RTCM-RTK type 18/19 message . . . . . . . . . . . . . . . . . . . . . . . Base Setup . . . . . . . . . . . . . . .
Select Character or String Response to Set Command . . . . . . . . . . . . 55 Query Sensor Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 Query Receiver Current Segment Number . . . . . . . . . . . . . . . . . . . . . 56 Store String . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 Query File Directory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 Configure Receiver in Daisy Chain Mode . . . . . .
Query SV Mode Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80 Use Unheathy SVs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80 Designate Satellites to Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 Set VDOP Mask . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 Query Week Number . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 Upload Waypoint to Sensor . .
Select Type Of EOT Character for RTCM Message . . . . . . . . . . . . 125 Compatible RTCM Message 18/19 Format . . . . . . . . . . . . . . . . . . . 125 Initialize RTCM Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125 Set Maximum Age of RTCM Differential Corrections . . . . . . . . . . 125 Define RTCM Message . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126 Disable Differential Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Appendix A. Photogrammtery & Event Marker . . . . . . . . . . . . . . . . . . . . . . . . . . A-1 Photogrammetry (Event Marking) Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . A-1 Time Tagging the Shutter Signal . . . . . . . . . . . . . . . . . . . . . . . . . . . A-2 Appendix B. Radio Link . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-1 Data Transmission Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
List of Figures List of Figures Z-12 Real-Time Sensor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Typical GPS Antenna . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Z-12 Real-Time Sensor Front Panel . . . . . . . . . . . . . . . . . . . . . . . . 8 Power Connector pin layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 DB9 Pin Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Null Modem Data Cable. . . . . .
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List of Tables List of Tables Accuracy as Function of Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Technical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Sensor Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Memory Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Z-12 Real-Time Sensor Front Panel . . . . . . . . . . . . . . . . . . . . . . . . 9 Power Connector Pinouts .
Table 4.24: Table 4.25: Table 4.26: Table 4.27: Table 4.28: Table 4.29: Table 4.30: Table 4.31: Table 4.32: Table 4.33: Table 4.34: Table 4.35: Table 4.36: Table 4.37: Table 4.38: Table 4.39: Table 4.40: Table 4.41: Table 4.42: Table 4.43: Table 4.44: Table 4.45: Table 4.46: Table 4.47: Table 4.48: Table 4.49: Table 4.50: Table 4.51: Table 4.52: Table 4.53: Table 4.54: Table 4.55: Table 4.56: Table 4.57: Table 4.58: Table 4.59: Table 4.60: Table 4.61: Table 4.62: Table 4.63: Table 4.64: Table 4.
Table 4.66: Table 4.67: Table 4.68: Table 4.69: Table 4.70: Table 4.71: Table 4.72: Table 4.73: Table 4.74: Table 4.75: Table 4.76: Table 4.77: Table 4.78: Table 4.79: Table 4.80: Table 4.81: Table 4.82: Table 4.83: Table 4.84: Table 4.85: Table 4.86: Table 4.87: Table 4.88: Table 4.89: Table 4.90: Table 4.91: Table 4.92: Table 4.93: Table 4.94: Table 4.95: Table 4.96: Table 4.97: Table 4.98: Table 4.99: Table 4.100: Table 4.101: Table 4.102: Table 4.103: Table 4.104: Table 4.105: Table 4.106: Table 4.
Table C.1: Page xvi Differential Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1 Overview The Z-12 Real-Time Sensor, Figure 1.1, processes signals from the Global Positioning System (GPS) satellite constellation. The sensor provides real-time position, velocity, and time measurements using twelve dedicated separate and parallel channels for Coarse/ Acquisition (C/A) code-phase, and carrier-phase measurement on the L1 (1575 MHz), and Precise (P) code phase and carrier phase measurem ent on L1 and L2 (1227 MHz) bands.
being compatible for differential and RTK operation with any other receiver that implements the RTCM standard. Figure 1.1: Z-12 Real-Time Sensor Functional Description The sensor is activated when power is applied to either of the two power connectors, and the power pushbutton is pushed to ON. After self test, the sensor initializes its 12 channels and begins searching for all satellites (SVs or Space Vehicles) within the field of view of the antenna. The sensor can track all Block I and Block II GPS SVs.
Real-Time Differential One of the most important functions of the sensor is providing real-time position solutions with accuracy ranging from centimeter level to 100 meters. Table 1.1 summarizes the positioning modes and expected accuracy. Table 1.
Data Collection for Post-Processing One independent measurement is collected per 0.2, 0.5, 1.0 second, or slower, depending upon whether the Q (Quick Position) option is installed in the sensor, with no interpolation or extrapolation from previous measurements. The measurements can be stored in internal battery-backed RAM, from which the data can be transferred later to a personal computer or output in real time via RS-232 serial ports.
Specifications and Options Introduction Technical Specifications Table 1.2 lists the technical specifications of the sensor. Table 1.2: Technical Specifications Characteristic Specifications Tracking 12 channels L1 CA/PL1 and PL2 Size 3.9H x 6.3"W x 8.8"D Weight 5.
If the letter or number is displayed in the response m essage, the option is available. If the letter/number is not displayed, the option is not available. Table 1.3 lists the available options when the $PASHQ,SCRN,8 command is submitted. Table 1.
2 Operation Equipment Description Antenna CAUTION Do not mount the GPS antenna near any metal objects, since these objects will reflect the GPS satellite signals causing multipath errors. Mounting the antenna higher will usually reduce the multipath effect. Figure 2.1 shows a typical GPS antenna. Figure 2.1: Typical GPS Antenna Operation Page 7 Operation The GPS antenna can be m ounted on a tripod, a hand-carried pole, a vehicle, or any suitable means.
Sensor Front Panel The Z-12 Real-Time Sensor operates with an input voltage between 10 and 32 Vdc from an external power supply. Two POWER-IN sockets let you use two external batteries. When only one battery is connected and it com es close to discharge, a continuous tone indicates that the voltage has dropped below 10 volts. You can connect the second battery to the second connector and continue recording data without interruption.
Table 2.1 describes the front panel components of the Z-12 Real-Time Sensor. Table 2.1: Z-12 Real-Time Sensor Front Panel Number Component Function Antenna RF connector The RF connector is a standard N-type female receptacle wired for connection via 50-ohm coaxial cabling to a GPS antenna with an integral LNA. The Ntype connector shell is connected to the Sensor common ground. The N-type connector center pin provides +9.5 VDC (to power the LNA) and accepts 1227 and 1575.
center pin provides +9.5 VDC (to power the LNA) and accepts 1575 MHz or 1227.60 MHz RF input from the antenna; the RF and DC signals share the same path. CAUTION The current is limited to 150 mA out of the RF center conductor. It is short-circuited protected. If using a splitter or other RF network, use an inner DC block suitable for 1-2 GHz, 50 ohms, maximum voltage 25 V to protect the Sensor from external voltages.
The voltage input range is 10-32 volts, with a power rating of 12 watts. WARNING Do not connect or disconnect power or signal cables from the Z-12 Real-Time Sensor while power applied. Possible injury and equipment damage may occur. Serial Port Configuration Figure 2.4: DB9 Pin Configuration Operation Page 11 Operation The Sensor provides three RS-232 serial ports with two-way full-duplex communication.
Table 2.3 lists the signal param eters for the three DB9 connectors. Table 2.3: DB9 RS-232 Connector Pinouts Port Pin Signal A 1 DCD1 Data Character Detect for port 1 2 RXD1 Receive Data for port 1 3 TXD1 Transmit Data for port 1 4 +12V1 Supply output for radio. Acts as DTR if necessary. 5 GND1 Signal Ground for port 1 6 DSR1 Data Set Ready for port 1 7 RTS1 Request To Send for port 1 8 CTS1 Clear To Send for port 1 9 1PPS One Pulse Per Second output.
Serial Null Modem Data Cable Table 2.5 shows the wiring information for the Null Modem data cable. Operation Figure 2.5: Null Modem Data Cable Default Parameters The default transmit/receive protocol is 9600 baud, eight data bits, no parity, and one stop bit (8N1). When you first establish communications with the Sensor, your communications interface must use this protocol.
Data Output Options All the default data output com mands are set to OFF. The Sensor will not output any data until you send a message commanding it to do so. Refer to “$PASHS,OUT” on page 87 for more information. Configuration Defaults To determine whether the Sensor has the Q option installed, refer to Table 1.3 on page 6. Table 2.4 lists the default settings for the Sensor operating configuration. Table 2.4: Operating Configuration Defaults Parameter Without Q Option* With Q Option* NAV cycle 1 0.
battery, thus maintaining data integr ity. Y ou can also operate the Sensor from tw o parallel batteries for longer se ssions. The Sensor is internally protected in case the battery connections ar e unintentionally reversed. Figure 2.6: Equipment cable connections in Differential Setup Powering On the Sensor 1. Operation After Sensor has been properly cabled, press the On/Off button to apply power.
Receiver Memory Reset 2. It is good practice to reset the Sensor to its factory defaults prior to operating it for the first time or when a system malfunction occurs. A reset of the internal memory clears the memory and restores the factory defaults. You can reset the Sensor internally using the reset plug supplied with the Sensor, or externally by issuing a command to the Sensor with an IBM-compatible personal computer (PC).
4. Monitoring Satellite Tracking For the following operations, the Sensor must be connected to a GPS antenna, and at least four satellites must be tracked. 6. After connecting the Sensor to an antenna which has a clear view of the sky, the Sensor should track satellites. When the Sensor is tracking satellites, the LED on the front panel flashes green for each satellite. For example, if the LED flashes green five times between red flashes, five satellites are being tracked. 7.
Ensur e you enter these commands. The first command enables NMEA output port A while the third one tells the Sensor to return GGA information through port A. The second one tells the NMEA output rate every 1.0 sec. For mor e information about these com mands, refer to Chapter 4, Command Response Formats. The response message is in NMEA 083 format with the structure: $GPGGA,hhmmss.ss,ddmm.mmmmmm,s,dddmm.mmmmmm,s,n, qq,pp.p,±hhhhh.hhh,M,,M,dd.ll,ssss where the fields are as defined in Table 2.5. Table 2.
To change the output rate, issue the command $PASHS,NME,PER,x w here x is the output rate in seconds. Example: GGA message, Autonom ous Position $GPGGA,015454.00,3723.285136,N,12202.238517,W,1,08,01.0,+00012. 384,M,,M,,0000 Example: GGA message, RTCM differential Example: GGA message, CPD differential (RTCM-RTK or DBEN) $GPGGA,015454.00,3723.285136,N,12202.238517,W,3,08,01.0,+00012. 384,M,,M,00.123,0000 9. To stop GGA output, issue the command $PASHS,OUT,A. 10.
Hardware Setup In the following setup, port B for both base Sensor and rover Sensor will be used for differential data link, while port A will be used for connecting to a PC and Sensor serial control. 1. Connect all the cables for the base Sensor and the rover Sensor as described in “Hardware Setup” on page 14. 2. Connect the port B of both base Sensor and the rover Sensor with provided serial cable. A typical differential system is depicted in Figure 2.6.
What if the Base Coordinates are Unknown? If you enter the base station coor dinates this w ay, any rover using differential data fr om the base station can still compute very accurate positions up to centimeter level, relative to the base station. But the absolute accuracy w ill only be as accurate as the accuracy of the autonomous position in the base station. CPD with DBEN message Examine the following items prior to conducting a software setup. 1. The hardware setup is complete and correct 2.
4. 5. 6. If applicable, measure and enter the antenna offset parameters: slant, radius, vertical offset, and horizontal offsets in distance and azimuth. For exam ple, to set antenna slant to 5 meters, $PASHS,ANH,5.0 A typical command to set antenna offset parameters could be $PASHS,ANT,1.678,0.1737,0.5,0000.00,0.0 To query current antenna parameters: $PASHQ,ANT The response would be $PASHR,ANT,1.67880,0.1737,00.5000,00000.00,00.0000*12 Enter the base station site ID.
9. The base Sensor is now operational. To verify it, connect port B to a PC at 9600 BAUD which is running a communication program, such as Ashtech’s REMOTE.EXE, one should see message starts with a header $PASHR,RPC would output on a one second interval. Rover/Remote Setup 1. 2. 4. 5. STATUS: MSMOD:01 Hz MODE: ROVER BASE STAT: 00000 PRN: 01 03 09 17 21 23 28 31 AGE: 394 ms RCVD CORD:008 SEC CORD USED: RECEIVED AMBIGUITY:FIXED RCV INTVL:01.
the Sensor can even take advantage of RTCM-com pliant m essages from receivers manufactured by other companies (such as the Trimble 4000SSi™). This design provides the versatility and performance necessary to complete any job requiring precision solutions. Table 2.
Table 2.7: Differential RTCM Message Types (continued) Mode Message Type Send Receive Description Expected Accuracy * Type 18/19A is for Ashtech-to-Ashtech operation. Choke ring antenna, short baseline, 1 Hz, fast CPD off Type 18/19B is for Ashtech-to-Trimble operation. Operation CAUTION Be aware that once RTCM base or rover mode is selected on a given port, all set and query command to that port will be ignored.
b. 5. $PASHS,RTC,SPD,9 Selects burst mode to output RTCM message. c. $PASHS,RTC,TYP,1,1 Selects Type 1 every second d. $PASHS,RTC,TYP,2,0 Disables Type 2 e. $PASHS,RTC,TYP,3,1 Selects Type 3 every minute f. $PASHS,RTC,TYP,6,OFF Disables Type 6 g. $PASHS,RTC,TYP,16,0 Disables Type 16 h. $PASHS,RTC,TYP,18,1 Selects Type 18/19 every second To verify the setup, send $PASHQ,RTC command to the Sensor. A typical response message would be STATUS: SYNC: AGE:0000 TYPE:18 QA:100.
3. 4. 5. 8. $GPGGA,015454.00,3723.285136,N,12202.238517,W,3,08,01.0,+00012. 384,M,,M,00.123,0000 RTCM differential (pseudo-range) with type 1 message Perform the following checklist prior to software setup. 1. The hardware setup is complete and correct. 2. All parameters are assumed to be at the factory default settings. Refer to “Receiver Memory Reset” on page 16 on how to reset the param eters to the factory defaults. 3.
4. 5. Send the following commands to the base Sensor $PASHS,RTC,BAS,B Configures the Sensor into RTCM base mode and use port B for output differential message. $PASHS,RTC,SPD,7 Selects the 300 bit-per-second speed to output RTCM m essage. By default the type 1 m essage will be output continuously to port B. To verify the setup, send $PASHQ,RTC command to the Sensor. A typical response message would be STATUS: SYNC: AGE:0000 TYPE:00 QA:100.
7. The rover Sensor is now operational. Refer to “Monitoring Position” on page 17 for more information on position information. A typical GGA message with fixed ambiguities would be $GPGGA,015454.00,3723.285136,N,12202.238517,W,2,08,01.0,+00012. 384,M,,M,002,0000 Position Update Rate Configuration Table 2.8: MSMOD data description x.x (second) Description Default Data Record/ Real-time output Interval (second) Default NMEA output interval (second) 1.0 1Hz position update rate 20.0 5.0 0.
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3 Understanding CPD This chapter provides CPD operation in more detail by describing monitoring the CPD solution, solution output and storage, trouble shooting and performance optimization. RTCM reference station setup is also described briefly. For detailed information on the commands and responses that are mentioned in this chapter, please refer to Chapter 4, Command Response Formats.
00.011,00.011,00.012,-00.000,+00.000,-00.000,221001,+000.000,000.001,+000.001, 00.000,00.000,00.000*6C In a CBEN message, the solution RMS values represent one-sigma solution accuracy. A fixed ambiguity solution should have all three RMS values < 0.03 meters, with PDOP < 4.0. You can also look at the $PASHR,CPD message for am biguities fixing status. Refer to “$PASHQ,CPD” on page 144. Solution Latency The GGA message contains a field which shows the solution latency. For example: $GPGGA,015454.00,3723.
To output the NMEA messages, use the $PASHS,OUT and $PASHS,NME commands. If for any reason the CPD solution cannot be com puted for an epoch, there will be no CPD solution output for that epoch in any real-time or NMEA m essage. Other solution messages are also available for query, and not to output periodically like PBEN or CBEN messages. These m essages are UBN and OBN. The U BN message gives CPD position, velocity, and statistical information in binary form at.
4. 5. 6. 7. To improve the vector solution, you may wait for 5-10 epochs of data before issuing the next set of com mands: $PASHS,SIT,???? $PASHS,CPD,FST,ON $PASHS,CPD,DYN,2 These three commands reset the unit for dynamic operation. The receiver will beep twice, indicating that the vector solution has been created. Wait for more than two seconds, and then enter the next command to log the solution to the OBEN file: $PASHQ,OBN Verify the site name in the vector solution. If it does not match, query again.
Troubleshooting The following problems are sometimes encountered by users new to Z-12 Real-Time Sensor. If your system isn’t working properly, please refer to this list. If you need further assistance, please call an Ashtech customer service representative. Table 3.1: Troubleshooting Tips Symptom Action LED displays constant amber Indicates the system is not operating. Try to clear internal/external memory with $PASH,INI.
Table 3.1: Troubleshooting Tips Symptom No CPD solution Action CPD solution is intermittent and the Rover beeps Cannot get fixed CPD solution CPD solutions are not being stored in the Rover Cannot get the CPD solution output in real-time Page 36 Verify that there are at least four common satellites between the base and the rover, using $PASHQ,CPD,INF command. Verify that base station coordinates have been received in the rover side, using $PASHQ,CPD,POS command.
System Performance Optimization CPD Solution Parameters Table 3.2 lists the commands which are provided for optimizing the CPD operations. Table 3.
If the ambiguities are fixed incorrectly, the satellite geom etry must change appreciably before the ambiguities will again fix correctly. For a static rover, this will happen within approximately 10 m inutes, or when a new satellite is acquired. Figure 3.1: Ambiguity Fix Test Results Dynamics: $PASHS,CPD,DYN Select the dynamics for the fastest acceleration you expect to be moving. If the dynamics are not set properly, the CPD solution will be less accurate.
assume limited vertical m ovement. AIRCRAFT dynamics assume higher speeds and accelerations.
It is im portant to set the rover’s update r ate to m atch the base’s DBEN m essage output interval. Initialization: $PASHS,CPD,RST If you wish to reset the carrier phase cycle am biguities that have been found, send $PASHS,CPD,RST command. Note that your position accuracy will temporarily degrade and you should wait until the ambiguities are fixed again before expecting centimeter accuracy.
Table 3.3 lists the recommended message schedules. Table 3.3: Default RTCM message schedules Message Type Interval (seconds) 1 1 2 0 (off) 3 60 (1 minute) 6 0 16 Off 18/19 1 Understanding CPD Page 41 Understanding For CPD (RTK) application only, you can turn on type 3 and type 18/19 only. For RTCM code differential only, you can turn on type 1 to be continuous and turn off all other message.
Page 42 Z-12 Real-Time Sensor Operation and Reference Manual
4 Command Response Formats Overview Com mand Response Formats Page 43 Command This section discusses the format and structure of the commands to and the responses from the sensor. As noted previously, an external device such as a personal com puter (PC) or a handheld controller must be used to input commands to the sensor, and to monitor responses from the sensor. All commands must be terminated with or , as appropriate for the external device.
Table 4.
Table 4.
Table 4.
Table 4.
Table 4.
Table 4.
General Sensor Commands The sensor commands are used to control various operations of the sensor, such as port selection, baud rate, type of output message, processing mode, etc.Table 4.2 summarizes the sensor commands. Table 4.
Table 4.
Table 4.2: General Sensor Commands (continued) Command Description Page $PASHS,VDP Set VDOP mask 81 $PASHQ,WKN Query week number 81 $PASHR,WKN Response message, week number 81 $PASHS,WPL Upload waypoint to sensor 81 $PASHS,ZMD Set sensor to Z mode 82 Query Satellites with Received Almanac $PASHQ,ALH This command asks for ALH message. This message contains the number of satellites with received almanac since the receiver was turned on. The port for the message output may be specified.
Set Antenna Height $PASHS,ANH This command sets the antenna height. The command structure is $PASHSANH,x.xxxx where x.xxxx is the height in meters. Maximum value is 6.4000. Example: Set antenna height to 2.0000 meters $PASHS,ANH,2.0000 Set Antenna Offsets $PASHS,ANT This command sets the antenna offsets from a reference point to the antenna phase center. Slant is measured from the reference point to the antenna edge. Radius is the distance from the antenna phase center to the antenna edge.
where each item is as described in Table 4.5. Table 4.5: Typical ANT Com mand Item Description $PASHS,ANT Message header 1.678 Specify antenna height as 1.678 meters 0.1737 Specify antenna radius as 0.1737 meters 0.0 0000.00 0.0 Specify antenna phase center height as 0.0 meters Specify antenna horizontal azimuth as 0000.00 degrees Specify antenna horizontal distance as 0.0 meters Query Antenna Parameters $PASHQ,ANT This command asks for the current antenna parameters.
Select Character or String Response to Set Command $PASHS,CACK The $PASHS,CACK,[1/0] com mand switches between single-character acknowledge/notacknowledge (ACK/NAK) response messages and string ACK/ NAK response messages. Table 4.7 lists the com mand structure and corresponding ACK/NAK response message. Table 4.
s = DL: DMA low power Example: $PASHR,CFG,LZ Low-power Z-12 receiver Query Receiver Current Segment Number $PASHQ,CRS This command requests the receiver current segment number. The structure is $PASHQ,CRS. The response is output from the port that received the request. $PASHR,CRS The response is in the form $PASHR,CRS,i where i is the current file index in the receiver external memory. Range of i is 0 through 99.
where the items in the response message are as defined in Table 4.8. Table 4.
Set Elevation Mask $PASHS,ELM This command sets the value of the SV elevation mask for data collection. The command structure is $PASHS,ELM,x where x is a number between 0 and 90 (default = 5 degrees). Example: Set elevation m ask to 10 degrees $PASHS,ELM,10 Set Static Site Occupation Counter $PASHS,EPG Set epochs to go (for kinematic use). Epochs to go is a counter used during kinematic surveys that specifies the number of data epochs to be collected at the current site.
Refer to Table 4.10. Table 4.10: FIL Structure Setting 999 Description Delete all image files in the receiver d Index of the file to be deleted * Delimiter between data and checksum h Byte wise XOR checksum in hex checksum beginning with PASHS (exclude '$' sign) Return message: 'C' Operation completed successfully If the file to be deleted is not the last file in the sensor, the sensor moves all the following files up and waits until the operation is complete.
receive the response. If the destination port is not specified, the response message goes to the port that received the request. $PASHR,FLS The response is a message in the form $PASHR,FLS,eeee,ttt,nn,ffff,dd.hh.mm,ffff where the fields are as described in Table 4.11. Table 4.11: FLS Structure Field eeee Descriiption Free memory in sensor external memory 0 through 6200 kilobytes ttt Total number of files currently in sensor 1 through 100 nn Number of files matching query criteria 1 through 10 ffff dd.
Table 4.12: Typical FLS Message (continued) Item Description 74560647 745th GPS week 6th day 06 th hour 47th minute 2051 size of file = 2051 kilobytes ???? Site name of 19th file 74631651 746th GPS week 3rd day 16th hour 51st minute 0003 size of file = 3 kilobytes *35 Checksum Set HDOP Mask $PASHS,HDP,X Reset Receiver Memory and Communication Parameters. $PASHS,INI This command resets the receiver memory and serial baud rate.
Table 4.13: Memory Reset Codes (continued) Field Description m Reset memory code: 0 = No memory reset 1 = Reset internal memory (ext RAM) 2 = Reset external memory (BBU- battery-backed-up) 3 = Reset internal and external memory c Modem initialization code (the comm. port the init string will be sent to) 0 = None) A or D Return message: None Select Ionospheric Model $PASHS,ION,X This command selects the ionospheric or tropospheric model for the position computation.
Set Longitude of Antenna Position $PASHS,LON Sets the longitude of the antenna used in differential base mode. The command structure is $PASHS,LON,dddmm.mmmmmmm,x where dddmm.mmmm is longitude in degrees (ddd) and decimal minutes (mm.mmmmmmm), and x is E (East) or W (West). The default is 0. Example: Set antenna longitude to 12159.8291219° west $PASHS,LON,12159.8291219,W $PASHQ,PAR The response message for the default values of query command $PASHQ,PAR is typically as shown below.
Table 4.14: Typical PAR Response Message (continued) Item HDOP Horizontal Dilution of Precision. Default is 4. VDOP Vertical Dilution of Precision. Default is 4. PEM Position Elevation Mask. Elevation below which the SV will not be used to compute a position. Default is 05 degrees. UNH Use unhealthy SVs for position computation. Values are Y (yes), N (no). Default is N. IONe Include or exclude ionosphere and tropospheric model in position computation. Values are Y (yes) and N (no). Default is N.
Set Photogrammetry Edge $PASHS,PHE This command selects the rising or falling edge of the photogrammetry edge. The structure is $PASHS,PHE,x where x is R for rising edge, F for falling edge. Example: Select falling edge: $PASHS,PHE,F This command requires that the P (Photogrammetry/Event Marker) option be installed in the sensor. $PASHQ,PHE The corresponding query command is $PASHQ,PHE,x where x is the port, A, B, or C, to output the message.
Example: Set minimum satellites to 4 $PASHS,MSV,4 Set PDOP Mask $PASHS,PDP,X This command sets the value of the PDOP m ask. The com mand structure is $PASHS,PDP,x where x is a number between 0 and 99. Position is not computed if the PDOP exceeds the PDOP mask. The PDP default is 40. Example: Set PDOP to 30 $PASHS,PDP,30 Set Position Elevation Mask $PASHS,PEM This command sets the elevation mask for position computation. The command structure is $PASHS,PEM,d where d is 0 to 90 degrees.
Table 4.15: PJT Structure (continued) Field Description aa Antenna number mmdd Month and day ii Operator ID 0 through 99 2 characters Comment, up to 13 characters Set Position Mode $PASHS,PMD Set Position of the Antenna $PASHS,POS This command sets the position of the antenna used in differential base mode. The structure is $PASHS,POS,ddmm.mmmmmmm,x,dddmm.mmmmmmm,y,sxxxxx.xx where the fields are as defined in Table 4.16. Table 4.16: POS Command Structure Field ddmm.
Table 4.16: POS Command Structure (continued) Field x dddmm.mmmmmmm y sxxxxx.xx Description North (N) or South (S longitude in degrees (ddd) and decimal minutes (mm.mmmmmmm) East (E) or West (W) ellipsoidal height in meters where s is the sign (+ or -) and xxxxx ranges from 0 to ±99999.99. Example: $PASHS,POS,3722.2912129,N,12159.7998265,W,+15.25 $PASHQ,POS The associated query command is $PASHQ,POS,x,*crc where x is the port A, B, or C.
Query Port and Baud Rate $PASHQ,PRT This command asks for the sensor port and baud rate. The structure is $PASHQ,PRT $PASHR,PRT The response is a message in the form : $PASHR,PRT,x,d where x is the specified port, and d is the baud rate index, as listed in Table 4.18. Table 4.
Reboot $PASHS,RBT Clear (reboot) internal RAM and reset sensor. Resets baud rate to 9600 baud. The structure is $PASHS,RBT. Set Recording Interval $PASHS,RCI This command sets the value of the interval during which raw data will be output or recorded. The command structure is $PASHS,RCI,x where x is an integer number between 1 and 999 seconds. Default is 20.0. With the Q option installed, the RCI values are as listed in . Table 4.
$PASHR,RDP The response message is in the form $PASHR,RDP,x,m ,c,l,r where the fields are as described in Table 4.20. Table 4.20: RDP Structure Field x mmm Description Output port A or B Modem mode TRS cc Channel 0 through 15 llll RF link speed 4800 or 9600 r RF sensitivity (squelch) 0, 1, 2 Example: $PASHR,RDP,A,TRS,7,9600,2 Example: Set port A, TRS, channel 2, 4800 baud, squelch 2 Turn Data Recording On/Off $PASHS,REC Command This command turns data recording on or off.
Set Type of Data $PASHS,RNG This command sets the data type mode. The command structure is $PASHS,RNG,x where x is 0 or 2: 0 = geodetic data (B-file) 2 = position data (C-file). Reset Parameters To Factory Defaults. $PASHS,RST This command resets the sensor to the factory defaults and clears all m emory. The structure is $PASHS,RST.
command, only the parameters listed in Table 4.21. . For a complete reset, use the Table 4.21: Parameters Reset by RST Com mand Parameter Description Default Value SETUP INTVL Recording interval 20.0 Hz 0.5 Hz 0.
Table 4.21: Parameters Reset by RST Command (continued) Parameter Description Default Value THIS COORDINATES XMIT INTVL Broadcast interval for BPS message. BPS message 30 seconds contains base station ground mark coordinates (if relevant) and antenna offset from reference point. This command is relevant only for base or RBP rover mode. ADVANCED PARAMS/ AMBIGUITY FIX MODE Confidence level for reliability of ambiguity fixed solution.
Table 4.21: Parameters Reset by RST Command (continued) Parameter Description Default Value CBEN Epoch-by-epoch solution Off MBEN Measurement data Off PBEN Position data Off SNAV Ephemeris data, binary only Off SALM Proprietary, binary only Off FORMAT Output format, ASCII/binary ASCII BAUD RATE Real-time message baud rate 9600 PULSE GENERATION PARAMETERS PERIOD Time span between 2 pulses 0.5 to 60 seconds OFFSET The range that PPS may be advanced or delayed from 000.
Table 4.21: Parameters Reset by RST Command (continued) Parameter CYCLE TIME Description Fast CPD update rate: Default Value 1 sec - no Q option 0.5 sec - Q option and internal memory cleared 1 or 0.
Upload Route Information $PASHS,RTE This command uploads a number of route information. The structure is $PASHS,RTE,d1,d2,d3...... where the fields are as described in Table 4.22. Table 4.22: RTE Structure Field Description d1, d2, d3...... Waypoint number 1 through 20 Example: $PASHS,RTE,3,7,12,13 Return message: None Save Parameters $PASHS,SAV Query Sensor Configuration $PASHQ,SCRN,8 The $PASHQ,SCRN,8 command queries the configuration and options of the sensor.
Table 4.23: Configuration and Options (continued) Field Description 3J16 Firmware version, 4 characters C05 C = coprocessor, 05 = sensor option 1C63 Channel version, 4 characters DP Options: D = differential, base or remote U = differential, rover only P = photogrammetry 12 Code option: 1 = P code L1 2 = P code L2 M Remote monitor Q 1/4-second (quick) update rate L Low-power (sleep) mode J Real-time Z option Enter Site ID $PASHS,SIT,X This command sets the site name.
Table 4.24: Communication Baud Rate (continued) Code Baud Rate Code Baud Rate 2 1200 7 38400 3 2400 8 57600 4 4800 9 115200 To resume communication with the sensor after changing the baud rate using this command, change the baud rate of the command device. Example: Set port A to 19200 baud $PASHS,SPD,A,6 Query Elapsed Time for Each Tracked SV Since Positioning Began $PASHQ,SRD This command asks for the elapsed time for each tracked satellite since positioning began.
Query Status of Currently Locked Satellites $PASHQ,STA This command asks for the status of currently locked satellites. The structure is $PASHQ,STA or $PASHQ,STA,x where x is the port to output the response. If no port is specified, the response is output from the port that received the request.
$PASHS,UNH,Y Designate Satellites to Use $PASHS,USE This command selects satellites to track or not track. The structure is $PASHS,USE,d,c where d = PRN number of the satellite (range from 1 to 32), and c = Y to use or N to not use. Example: Use (track) satellite 15 $PASHS,USE,15,Y Set VDOP Mask $PASHS,VDP This command sets the value of the VDOP mask. The structure is $PASHS,VDP,x where x is 0 to 99. The VDOP default is 4. VDP is not used in CPD.
where the fields are as described in Table 4.27. Table 4.27: WPL Structure Field ddmm.mmmm y ddmm.mmmm x ww nnnnnnnn Description dd = degree part of latitude 0 through 90 mm.mmmm = decimal minutes 0 through 59.9999 Direction of latitude S = south N = north dd = degrees of longitude 0 through 180 mm.mmmm = decimal minutes 0 through 59.9999 direction of longitude E = east W = west Waypoint number 0 through 99 Waypoint name up to 7-character string Example: $PASHS,WPL,3722.3871,N,12159.
Raw Data Commands Table 4.28 summarizes the raw data commands. Table 4.
Query CBEN Message $PASHQ,CBN This command asks for the CBN message. This command queries only the current epoch. For query about bufferized message, use the $PASHQ,UBN command. The command strtucture is $PASHQ,CBN,c1*crc $PASHR,CBN The response message is in the form $PASHR,CBN,... This response message displays ASCII information on epoch-by-epoch solutions. The structure is $PASHR,CBN,xx,xx,xx.xx,ssss,xx,xxx.x,xx,xx.xxxxxxx,s,xxx,s,±xxx.xxx,xx.xxxx,x x.xxxx,xx.xxxx,±xx.xxx,±xx.xxx,±xx.xxx,ABCDEF,±xxx.
Table 4.30: Epoch Inform ation Structure (continued) Field Description ±xx.xxx Cross correlation of YZ ±30 meters ABCDEF Solution type flag containing 6 fields, 8 bytes. ±xxx.xxx East velocity - 1000 to +1000 meters\sec ±xxx.xxx North velocity - 1000 to +1000 meters\sec ±xxx.xxx Up velocity ± 1000 meters\sec xx.xxx Standard deviation of east velocity 0 to 16.0 meters/sec xx.xxx Standard deviation of north velocity 0 to 16.0 meters/sec xx.xxx Standard deviation of up velocity 0 to 16.
in this command. If the port is not specified, the message is output to the port from which this command was received. This query is relevant only if the receiver is in CPD mode and the dynamic parameter is set to static (antenna on tripod, not on manual pole). The command structure is $PASHQ,OBN,x where x is the serial port for message output, A or B $PA SHR,OBN The response message displays information about vector solutions accumulated from the beginning of a static site occupation.
Table 4.32: OBN (Binary Data) Structure. (continued) Field Type Description Number of epochs available Number of epochs used for solution Number of satellites used for solution Reference satellite PRN PRNs of used satellites L1 ambiguitiy, 0.01 cycle Number of epochs for each satellite Standard deviation of L1 ambiguity, cycles L2 ambiguity, 0.
$PASHS,OUT,c,d1,d2,d3....... where data types d1, d2, d3......can be specified; data types listed in Table 4.33 can be concatenated, must be delimited by comma [,]. Table 4.
where the fields are as defined in Table 4.34: PBEN Data structure Field Description f1 Receiver time in seconds of week when code is received 0 through 604800.00 f2 Station position ECEF-X ±9999999.9 meters f3 Station position ECEF-Y ±9999999.9 meters f4 Station position ECEF-Z ±9999999.9 meters d1 Latitude degrees 0 through 90 f5 Latitude minutes 0 through 59.
where the items in the message are as described in Table 4.35. Tab le 4.35: RAW Message Structure Item RCI:020.0 Description Send or record interval of the data in seconds. Default is once every 20 seconds for 1 HZ NAV cycle. The default is 0.2 or 0.5 second for 5 Hz or 2 Hz NAV cycle, respectively. MSV:3 Minimum number of SVs for the data to be sent or recorded ELM:05 Data elevation mask. The elevation below which data from that satellite will not be recorded. Default is 10 degrees. REC:Y ANH:0.
where the fields are as defined in Table 4.36. Table 4.36: UBN Structure Field Description g GPS time since 1/5/80 in seconds n Number of solutions and head/tail selector t Time interval between output solutions constant 1 second x Port for message output, A or B Example: $PASHQ,UBN,0.0,+1,1.0 $PASHR,UBN The response is a message in the form $PASHR,UBN, where the structure is as defined in Table 4.37. Table 4.
Table 4.
NMEA Data Message Commands NMEA data message com mands can be sent to the sensor through serial port A, B, or C, and can also be directed so the m essage is output through port A, B, or C. The general format for the NMEA message set com mands is: $PASHS,NME,str,x,y The command enables or disables NMEA message type str on port x, where x is A, B, or C, str is one of the following three-character strings GLL BWC GXP DAL GGA GSA VTG GSV GSN TTT MSG RRE APA ALM MSG GRS UTM SAT XTE Table 4.
Table 4.39 summarizes the NMEA commands. Table 4.
Table 4.
where each field is as described in Table 4.40. Table 4.
Table 4.41: Autopilot APA Structure (continued) FIeld eee.eee s Description (continued) Cross-track error 0 through 999.
Table 4.42: BWC Structure (continued) Field ddd.ddd ppp Description Distance (N for nautical miles) 0 through 999.999 Waypoint identifier 3-character string Example: $GPBWC.015454.00,0000.000,N,00000.0000,E,069.00,T,84,73,M,999.999,N,001 NMEA Decimal Almanac Message $PASHS,NME,DAL This message displays the NMEA almanac message in DAL format. The structure is: $PASHS,NME,DAL,ss,hhh,e.eeeeeeeE±99,ttttttt,i.iiiiiiiE±99,±a.aaaaaaaE±99, ±m.mmmmmmmE±99,±c,cccccccE±99, c.
$GPDAL,14,00,5.2795410E-03,032768,3.065721E-01,-2.4811015E09,5.1536948E03,5.8827317E-01,8.8243234E-01,-8.8568139E-01,8.201599E05,7.2759576E-12,571 GGA (GPS Position) Message $PASHS,NME,GGA,X ,Y This command enables/disables the NMEA GPS position response message on port x, where x is either A, B, or C, and Y is ON or OFF. This message is not output unless position is computed. Example: Enable GGA on port A $PASHS,NME,GGA,A,ON followed by output command $PASHS,OUT,x,NMEA where x is the output port.
Example: Set: $PASHS,NME,GGA,A,ON Typical Response: $GPGGA,183805.50,3722.36223,N,12159.82741,W,2,03,02.8, +00016.12,M,31,M,005,0001*6F Table 4.45 describes each item in the response message.
Table 4.45: Typical GGA Response Message Item $GPGGA 183805.50 Description Header Time of position computation 3722.36223 Latitude N N North 12159.82741 Longitude W West 2 Differential mode 03 Number of SVs used in position computation 02.8 HDOP +00016.12 Altitude M Meters. Units of altitude. 31 Geoidal separation M Meters.
where each field is as described in Table 4.46. Table 4.46: GLL Structure Field Description ddmm.mmmmm Latitude component of position, ddmm.mmmmm, in degrees, minutes and decimal fraction of minutes s dddmm.mmmmmm s hhmmss.ss s *cc Latitude sector, s = N - North, s = S - South Longitude component of position, dddmm.mmmmm, in degrees, minutes and decimal fraction of minutes.
Example: Enable GRS message on port C $PASHS,NME,GRS,C,ON followed by output com mand $PASHS,OUT,x,NMEA where x is the output port. $GPGRS The response message is in the form $GPGRS,hhmmss.ss,m,sxx.x,sxx.x,sxx.x,....*cc Range residuals are recomputed after the GGA position is computed. Therefore the mode m is alw ays 1. There will be a range residual sxx.x for each satellite used in position com putation, and the order of the residuals m atches the order of the satellites in the GSS m essage. Table 4.
Table 4.49: Typical GRS Response Message (continued) Item Description -00.4 Range residual for second SV in GSS message +00.2 Range residual for third SV in GSS message +00.5 Range residual for fourth SV in GSS message +00.7 Range residual for fifth SV in GSS message -00.
NMEA GSN (Signal Strength/Satellite Number) $PASHS,NME,GSN,X ,Y This command enables/disables the signal strength/satellite number response message on port x, where x is either A, B, or C, and y is ON or OFF. Example: Enable GSN message on port C $PASHS,NME,GSN,C,ON followed by output command $PASHS,OUT,x,NMEA where x is the output port. $GPGSN The response is a message in the form : $GPGSN,qq,pp,ss,ss,.....
Table 4.52: Typical GSN Message (continued) Item 039 16 Description Signal strength of the second SV PRN number of the third SV 021 Signal strength of the third SV 999 Termination when no RTCM information 7d Message checksum in hexadecimal NMEA GSV (Satellites-In-View) $PASHS,NME,GSV,X ,Y This command enables/disables the satellites-in-view m essage to send out of serial port, where x is port A, B or C, and y is ON or OFF.
$GPGSV The response message is in the form : $GPGSV,d1,d2,d3,d4,d5,d6,d7,d8,d9,d10,d11,d12,d13,d14,d15, d16,d17,d18,d19*CC where the fields are as defined in Table 4.53. Table 4.
Table 4.
Table 4.55: Typical GXP Response Message (continued) Field ddmm.mmmmm s dddmm.mmmmm s Description Latitude component of position, ddmm.mmmmm, in degrees, minutes and fraction of minutes Latitude sector N = North S = South Longitude component of position, dddmm.mmmmm, in degrees, minutes and fraction of minutes Longitude sector E = East W = West Example: Set: $PASHS,NME,GXP,A,ON Response:$GPGXP,183805.00,3722.36221,N,12159.82742,W*5C where each item in the response is as described in Table 4.56. Table 4.
$GPMSG The response message format depends upon the RTCM message type enabled: type 1 is enabled by default; types 3, 6, 9, and 16 must be enabled by the $PASHS,RTC,TYP command. The format for RTCM message types 1 and 9 is: $GPMSG,rr,ssss,zzzz.z,s,h,ccc,hhmmss:ss,e,vv,spppp.pp,sr.rrr,iii*cc where the fields are as defined in Table 4.57. Table 4.57: Structure for RTCM Message Types 1 and 9 Field rr ssss zzzz.
where each item is as described in Table 4.58. Table 4.58: Typical RTCM Message Types 1 and 9 Item $GPMSG 01 0000 2220.0 1 0 127 003702:00 Description Header RTCM message Station ID Z count in seconds and tenths Sequence number Station health Total number of characters of the time item Current time in hours, minutes, and seconds 2 UDRE for SV 12 12 Satellite PRN number -0081.30 PRC for SV 12 +0.026 RRC for SV 12 235 IODE for SV 12 2 UDRE for SV 13 13 Satellite PRN number PRC for SV 13 +0.
Table 4.58: Typical RTCM Message Types 1 and 9 (continued) Item Description 145 IODE for SV 27 7A Message checksum in hexadecimal The structure for RTCM message type 3 is: $GPMSG,rr,sss,zzz.z,s,h,ccc,hhmmss:ss,sxxxxxxx.xx,syyyyyyy.yy, szzzzzzz.zz where the fields are as defined in Table 4.59. Table 4.59: Structure for RTCM Message Type 3 Field rr sss zzz.z Description RTCM type station identifier, 0000 to 1023 Z count in seconds and tenths, 0000.0 to 3600.
Table 4.60: Typical RTCM Message Type 03 (continued) Item Description 038 Total number of characters after the time item 231958:00 Current time in hours, minutes and seconds -2691561.37 Station X component -4301271.02 Station Y component +3851650.
Table 4.62: Typical RTCM Message Types 6 and 16 (continued) Item 1209.6 5 0 038 232008:00 TEXT 5C Description Z count in seconds and tenths Sequence number Station health Total number of characters after the time item Current time in hours, minutes and seconds Message content Message checksum in hexadecimal Set NMEA Send Interval $PASHS,NME,PER,X Set the send interval of the NMEA response messages in seconds. The structure is $PASHS,NME,PER,x where x is a any half-second or full-second value between 0.
A range residual (xxx.x) is computed for each satellite (ss) used in position computation. Residuals and position errors not computed unless at least 5 satellites are used in position computation. The fields in the RRE message are as defined in Table 4.63. Table 4.63: RRE Structure Field Description qq Number of satellites used to compute position ss PRN number for each of the satellites used in position computation s,xxx.x..... hhhh.h vvvv.v + or - and xxx.
Table 4.64: Typical RRE Response (continued) Item 0001.3 76 Description Vertical position error in meters Message checksum in hexadecimal NMEA SAT (Satellite Status) Message $PASHS,NME,SAT This command enables/disables the satellite status m essage. The srructure is $PASHS,NME,SAT,x,y where x is the output port A, B, or C, and y is ON or OFF. Example: Enable SAT message on port B $PASHS,NME,SAT,B,ON followed by output command $PASHS,OUT,x,NMEA where x is the output port.
Query: $PASHQ,SAT,B or Set: $PASHS,NME,SAT,B,ON Typical Response: $PASHR,SAT,03,03,103,56,60,U,23,225,61,39,U,16,045,02,21,U*6E where each item is as described in Table 4.66. Table 4.
$PASHS,OUT,x,NMEA where x is the output port. There is no query command for TTT. $PASHR,TTT The response is a message in the form : $PASHR,TTT,x,hh:mm:ss.sssssss*cc where each field is as defined in Table 4.67. Table 4.67: TTT Structure Field x hh:mm:ss.sssssss Description Day of GPS week, 1 to 7, where Sunday = 1 Time in hours, minutes, seconds Example: Enable TTT event marker on port A Set: $PASHS,NME,TTT,A,ON Typical Response: $PASHR,TTT,6,20:41:02.0000000*OD where each item is as described in Table 4.
Table 4.69: NMEA UTM Structure (continued) Field Description eeeeeee.ee East UTM coordinate 0 through 9999999.99 meters nnnnnnn.nn North UTM coordinate 0 through 9999999.99 meters q GPS quality indicator 1 = GPS available 2 = RTCM differential available 3 = Carrier phase differential (CPD) available ss Number of satellites being used 3 through 12 hh.h HDOP 0 through 99.9 aaaaa Antenna height in meters -1000 through 18000 ggg.g Geoidal height in meters -999.9 through 999.
$GPVTG,ttt,c,ttt,c,ggg.gg,u,ggg.gg,u*cc where each field is as defined in Table 4.70. Table 4.70: VTG Structure Field Description ttt True track/true course over ground, ttt = 000 to 359 degrees c True course over ground marker, c = always T (true course) ttt Magnetic track/magnetic course over ground, ttt = 000 to 359 degrees (output only if magnetic variation option (M) is installed in receiver) c Magnetic course over ground marker, c = always M (magnetic course) ggg.gg u ggg.
NMEA Message VTG (COG/SOG) $GPVTG This message displays the vehicle course over ground (COG) and speed over ground (SOG). The structure is $GPVTG,ccc,T,ccc,M,sss.ss,N,,sss.ss,K where the fields are as described in Table 4.72. Table 4.72: VTG Structure Field ccc,T ccc,M Description COG (Course Over Ground) and T for true north 0 through 359 degrees COG and M for magnetic variation north 0 through 359 degrees sss.ss,N SOG (Speed Over Ground) and N for knots 0 through 999.99 knots/hour sss.
Example: $GPXTE,A,A,019.999,R,N RTCM Commands Table 4.74 summarizes the RTCM commands. Table 4.
Example: Turn auto differential m ode on $PASHS,RTC,AUT,Y Set Receiver as Differential Base Station $PASHS,RTC,BAS Set the sensor to operate as a differential base station using RTCM format. The command structure is $PASHS,RTC,BAS,x where x is the differential port and can be set to A, B, or C. Example: Set to RTCM differential base m ode using port B $PASHS,RTC,BAS,B $PASHQ,MSG The associated query command is $PASHQ,MSG,x where x is port A, B, or C.
There is no response message. This command requires that the RTCM Differential or RTCM Remote Only options (D or U, respectively) be installed in the sensor. Select Type Of EOT Character for RTCM Message $PASHS,RTC,EOT Selects the type of EOT characters to be transmitted at the end of an RTCM message.
structure is $PASHS,RTC,MAX,x where x is any number between 1 and 1199. Default is 60. Used only in REMOTE m ode. Define RTCM Message $PASHS,RTC,MSG Define RTCM message up to 90 characters long that will be sent from the base to the remote. The command structure is $PASHS,RTC,MSG,x where x is the tex messaget. Used only if message type 16 is enabled.
Check Sequence Number $PA SHS,RTC,SEQ Checks sequence number of received m essages7 and, if sequential, accept corrections; if not, don't use correction. The command structure is $PASHS,RTC,SEQ,x where x is Y (check) or N (do not check). Default is N. Used only in REMOTE mode. Valid only at beginning of differential operation. After two sequential RTCM corrections have been received, differential operation begins.
Set Health of Reference Station $PASHS,RTC,STH This command sets the health of the reference station. The command structure is $PASHS,RTC,STH,x where x is any value between 0 and 7. Used only in BASE mode. Default is 0. The codes for the station health are definedby RTCM as listed in Table 4.77. Table 4.77: Station Health Codes Code Health Indication 7 Reference station not working. 6 Reference station transmission not monitored. 5 Specified by service provider. 4 Specified by service provider.
x is the type and y is the period. Used only in BASE mode. Table 4.78 indicates the Table 4.78: Types of RTCM Messages Type Range 1 0 to 99 seconds, where 0 is disabled and 99 is generated continuously 3 0-99 minutes, where 0 is disabled and 99 is generated continuously 6 1 = ON, 0 = OFF 9 Same as type 1. Sensor can not output type 9. 16 Default = OFF Same as type 3 18 19 types of messages available and the period range setting.
Table 4.79 describes each item of the message. Table 4.79: RTC Message Structure Item Page 129 Description STATUS Asterisk (*) denotes sync to last received RTCM message between base and remote stations (remote only). TYPE RTCM message type being sent (base) or received (remote). Types 1,2,3,6,16,18/ 19 STID Station identification received from the base station. 4 characters, 0 through 1023 STHE Station health received from the base station. See $PASHS,STH for details.
If any of these parameters is changed by the corresponding set com mand, send the corresponding query command to obtain the current status. If changed, use the $PASHS,SAV,Y set command to save the values. After the next power-up, the message displayed in response to the corresponding query com mand will display the saved values instead of the defaults. The set command $PASHS,RST always resets the parameters to the default values.
CPD Commands Table 4.81 summarizes the CPD commands. Table 4.
Set Integer Ambiguity Parameter $PASHS,CPD,AFP This command sets the integer ambiguity fixing param eter. The command structure is $PASHS,CPD,AFP,f1,*crc where field f1 is as defined in Table 4.82. Table 4.82: AFP Structure Field f1 Description Ambiguity fixing parameter. Range 1 through 5. *crc Example: Set ambiguity fixing parameter to 4: $PASHS,CPD,AFP,4 Set Antenna Parameters Of Other Receiver $PASHS,CPD,ANT OR $PASHS,BPS,ANT Table 4.
Example: $PASHS,CPD,ANT,1.790,0.1737,0.0,0000.00,0.0 $PASHQ,CPD,ANT OR $PASHQ,BPS,ANT The accompanying query commands are $PASHQ,CPD,ANT and $PASHQ,BPS,ANT. These com mands ask for inform ation about the OTHER sensor's antenna param eters. The port for the message output may be specified in this command. If the port is not specified, the message is output to the port from which this command was received The command structure is $PASHQ,CPD,ANT,c1*crc where c1 is the port for message output, port A, C, or C.
$PASHR,CPD,DLK The response is a message in the form $PASHR,CPD,DLK,mmm,b,n,......where the fields are as defined in Table 4.85. Table 4.85: DLK Message Structure Field mmm Description Receiver mode: BAS = base ROV = rover RBB = RBR = OFF = off Following message available only when sensor is not in OFF mode.
where the field parameters are as defined in Table 4.86. Table 4.86: CPD DYN Structure Field d1 *crc Description Dynamic - one of the following values: 0 = static (antenna on tripod) 1 = quasistatic (antenna on hand-carried pole) 2 = walking 3 = automobile 4 = aircraft 5 = ship Checksum Example: Set dynamic for autom obile: $PASHS,CPD,DYN,3 Set Current Raw Position $PASHS,CPD,ENT Set current raw position as BASE position. The command structure is $PASHS,CPD,ENT*crc where *crc is the checksum.
Enable/Disable Fast CPD Mode $PA SHS,CPD,FST This command enables/disables fast CPD mode. If this m ode turned on, the rover receiver performs a fast CPD position solution. This com mand is relevant for ROVER mode only. The command structure is $PASHS,CPD,FST,s1*crc where the field parameters are as defined in Table 4.88. Table 4.
Table 4.89: CPD INF Structure (continued) Field Description d2 SVPRN for the Svs in base sensor c2 Warning field description: + - no warnings C - warning in L1 measurements P - warning in L2 measurements - - warning in both measurements + - C P 1-32 ......... repeats d2c2 for other SVPRNs in base station d10 Number of Svs in the rover station. This determines the number of fields to follow.
Example: Set mode to CPD, reverse vector processing, rover $PASHS,CPD,MOD,RBR $PASHQ,CPD,MOD The accompanying query command is $PASHQ,CPD,MOD. This command requests information about current CPD mode. The port for the message output may be specified in this command. If the port is not specified, the message is output to the port from which this command was received. The command structure is $PASHQ,CPD,MOD,c1*crc where C1 is the port, A, B, or C.
Example: $PASHR,CPD,MOD,BAS,FST,A,2,1,RPC,SMS,111,ETD,10,CPD,AUT,2*crc Select CPD processing cycle $PASHS,MSMOD This command sets the repetition rate for CPD processing. The structure is $PASHS,MSMOD,f where ƒ is 0.2, 0.5, or 1 second. This command requires that the Q option be installed in the sensor. Be aware that this com mand initiates a power cycle and will require you to reinitialize differential parameters.
$PASHS,CPD, OUT,d1*crc where the field parameters are as defined in Table 4.93. Table 4.93: Solution Selection Field Description d1e 0=raw pseudo range solution (autonomous) 1=CPD solution if available Note: When the receiver is set to ROVER mode and the CPD solution is not available, no solution will be output to the serial port. However, the raw pseudo-range solution will be stored into the external RAM.
where d1 is as defined in Table 4.94. Table 4.94: PEB/PER Structure Field Description d1 Base coordinates broadcast interval in seconds. Only the following values are valid: 0, 10, 30, 60, 120, 300 means no transmision. second *crc Example: $PASHS,BPS,PER,30 Set DBEN Transmission Period $PASHS,CPD,PED OR $PASHS,DBN,PER This command sets the DBEN message transmission period; relevant only for BASE mode or RBP ROVER mode.
Example: Set position of other receiver: $PASHS,CPD,POS,3722.2432438,N,12350.5438423,W,+34.567 $PASHQ,CPD,POS OR $PASHQ,BPS,POS The accompanying query commands are $PASHQ,CPD,POS and $PASHQ,BPS,POS. These com mands request information about the OTHER receiver's position. The port for the message output may be specified in this command. If the port is not specified, the message is output to the port from which this command was received.
Select Output Port for DBEN and BPS Messages $PASHS,CPD,PRT This command selects the serial port that will output DBEN and BPS m essages; relevant only to BASE or RBP ROVER mode. The command structure is: $PASHS,CPD,PRT,x where x is port A or B. Example: Output DBEN and BPS messages on port B: $PASHS,CPD,PRT,B CPD Status $PASHQ,CPD The $PASHQ,CPD command requests the current CPD status. The return message is typically: STATUS: MSMOD:02 Hz MODE:DISABLED BASE STAT:00000 PRN: INTVL:01.0 sec RCV INTVL:01.
Table 4.97: CPD Status Message Structure (continued) Parameter Description BASE STAT A -1 if the receiver has not tracked the L2 observables B - 1 if the entered position and computed position differ by more than 500 metres in any direction C - 1 if the base station has not cimputed position using the raw pseudo-ranges D - 1 if base station antenna parameters are all zeros. E - 1 if the base station coordinates are not entered.
Table 4.97: CPD Status Message Structure (continued) Parameter CPD PER Description CPD update period (Rover ): Fast CPD OFF 1 1Hz and Fast CPD ON 1 1Hz or 2Hz and Fast CPD ON 2 where c1 is the port for message output, port A, B, C, or D. Query CPD Solution Status $PASHQ,CPD,STS This command asks for the CPD solution status message. This message contains information about current CPD processing status. The command structure is $PASHQ,CPD,STS,x where x is the port for message output, port A or B.
where the field parameters are as defined in Table 4.99. Table 4.99: Base Position - Rover Field Description d1 Solution output selection: 0 = Use entered base position 1 - Use transmitted base position *crc Checksum Example: Use transmitted base position $PASHS,CPD,UBP,1 Display Station Coordinates $PASHR,BPS This response message displays station’s coordinates. The command has a fixed length of 96 bytes, not including .
Table 4.
In the above table, s1 is a hex-coded one byte of status flag, as defined inTable 4.101. Table 4.101: Status Flag Bit Description 1 (LSB) Base station coordinates not entered 2 Base station antenna offset is not entered (This is questionable.
Query Sensor ID and DBEN Message Type $PA SHQ,IDR The associated query com mand is $PASHQ,IDR, and the response message is in the form: $ssddR,ttt Example: Query: $PASHQ,IDR Response: $BS??R,RPC Packed DBEN $PASHR,RPC DBEN is a packed message which contains one epoch of GPS pseudo-range and carrier phase measurements. It is an essential m essage which is used for CPD operation. The response message is in the form $PASHR,RPC, where the field structure is as defined in Table 4.103.
Table 4.104: Packed Data Field Structure (continued) Data Type long Symbol Range Compress Num. Bits Resolution PRN 32 Description SVPRN for the satellites which have data in this message. It is a bitwise indication. Starting from the LSB, bit 1 corresponds to SVPRN #1, bit 2 to SVPRN #2, and so on. Bit value of 1 means that SVPRN has data in message; otherwise 0. Table 4.105 defines the data that will repeat for each satellite whose corresponding bit in PRN is 1. Table 4.
in which ceil (a) means truncates to +Inf, e.g., ceil (3.1) = 4, ceil (3.5) = 4, ceil (3.95) = 4. NSVS is number of SVs. Table 4.106 defines the DBEN message size. Table 4.106: DBEN Message Size Num SVs 4 5 6 7 8 9 10 11 12 bits 808 952 1096 1240 1384 1528 1672 1816 1960 byte 101 119 137 155 173 191 209 227 240 Report Real-Time Error $PASHR,RTR This command returns a real-time error m essage in the form $PASHR,RTR,d where d is a hex listing as defined in Table 4.
Command Com mand Response Formats Page 152
A Photogrammtery & Event Marker Photogrammetry (Event Marking) Interfaces When the event [P] option is installed, the sensor can measure and record event times with high accuracy. In order to store an event time in the sensor's memory, a trigger signal must be applied to the appropriate connector located on the panel of the sensor; in the sensor, this connector is pin 9 of serial port B.
Therefore, setting the interval parameter to 1 second ($PASHS,RCI,1) yields the highest event time record rate. Because the 1 PPS signal is being used to record the photogrammetry events, the period of the 1 PPS signal needs to be set to a value equal to or less than the period of the EVENT pulse. The trigger pulse may be TTL-compatible or open collector. Minim um pulse duration is 100 nanoseconds when the signal is not terminated at the sensor input. The impedance is approximately 2K ohms.
B Radio Link Careful consideration must be given to the following situations to get the full perform ance from the radio data link: Data Transmission Rate To provide real-time, accurate rover position solutions at a 1-second rate, the Real-time Z system requires radios which can transmit data at a speed of at least 4800 baud. For best performance, radios capable of a 9600 baud data link speed are strongly recom mended, especially for RTCM operation with type 18/19 messages.
Sensitivity Sensitivity of the transmitter and the receiver should be properly selected depending on the area and the amount of interference. For the base station, the recommended sensitivity setting is low while for the rover station, it is medium or high. If you select a channel and you notice that the radio status light is blinking, there is probably someone broadcasting on that frequency and you should select different channel if you have another available.
C This appendix presents a brief overview of real-time differential, including code differential and carrier phase differential, sources of error, differential data m essages. Differential remote/rover and base operations are available as receiver options. The RZ sensor is capable of both code-based differential and carrier phase differential.
Carrier Phase Differential (CPD) In CPD mode, the pseudo-range and carrier phase measurement data, which are coded in a DBEN message format, or RTCM Types 18 and 19, are transmitted from the base station to the rover station. This allows the rover station to compute very accurate differentially corrected positions. The real-time Z system utilizes Ashtech’s PNAV data processing engine, which processes the raw measurement data from both base receiver and the rover in doubledifference form.
Sources of Error Error source affecting the performance of the real-time differential GPS can be categorized into two groups - those that affect the Z-12 sensor and those that affect the data link. Sensor Related Errors The major sources of error affecting the accuracy of DGPS solution are SV orbit estimation, SV clock estim ation, ionosphere, troposphere, sensor noise and multipath in the measurements, carrier phase integer ambiguities in carrier phase differential.
measurements and reduce the sensor noise and multipath. After locking to a satellite, the rms noise of the smoothed pseudo-range is reduced with the square root of n where n is the number of measurements. Satellite Geometry The recommended satellite geom etry is to have the RZ Sensor (both base and rover) track at least 5 common satellites above the elevation mask angle with the PDOP (Position Dilution of Precision) less than 4. Of course, the more satellites the receivers track, the better.
Selective Availability SA Error = 0.5 * a * t2 (meters) Where a is the SA acceleration in meters /second2, currently it is about 0.01 meters / second2 and it is subject to change by DoD without notice; t is the delay in the radio link. For example, for a 2 second delay the error due to SA is roughly 0.02 meters. Differential Message Table Table C.1 shows the differential m essage type supported in RZ Sensor. Table C.
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Glossary Almanac A comprehensive database of all pertinent information for all satellites- orbit, position, health, etc. Altitude hold A means of reducing the number of satellites to 3 for a position computation. If altitude is not held (fixed), 4 satellites are required. Altitude hold is seldom required now that a full constellation of satellites is available. Autonomous A GPS position determined by a single sensor without reference to a precise known location.
for one specific satellite. Fast CPD An Ashtech proprietary differential technique to generate position at high output rate and low latency. Fixed Ambiguities The Carrier Phase Cycle Ambiguities are of integer natures. When they can be fixed to integers, the position accuracy is in centimeter to sub-centimeter level. Float Ambiguities The Carrier Phase Cycle Ambiguities are estimated as float numbers. With float ambiguities, the expected position accuracy is around meter to sub-meter level.
SA Selective Availability. Intentional degrading of GPS signal by U S Department of Defense to hamper use by enemy. Can be mostly nullified by differential operation. SV space vehicle (satellite) Glossary UBN Output message containing CPD position, velocity, and statistical information. Binary only. UDRE User differential range error Week number Sequential GPS week number measured from 1/ 5/80. Z mode, Z-tracking™ Ashtech proprietary method for achieving precise position when Anti-Spoofing (AS) is on.
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Index Symbols Index Index $GPALM, 95 $GPAPA, 96 $GPBWC, 97 $GPDAL, 99 $GPGGA, 99 $GPGLL, 101 $GPGRS, 103 $GPGSA, 104 $GPGSN, 105 $GPGSV, 107 $GPGXP, 108 $GPMSG, 110 $GPRRE, 114 $GPVTG, 120, 121 $GPXTE, 121 $PASHQ,ALH, 52 $PASHQ,ANT, 54 $PASHQ,BPS,ANT, 134 $PASHQ,BPS,POS, 143 $PASHQ,CBN, 84 $PASHQ,CFG, 55 $PASHQ,CPD, 144 $PASHQ,CPD,DLK, 134 $PASHQ,CPD,MOD, 139 $PASHQ,CPD,POS, 143 $PASHQ,CPD,STS, 146 $PASHQ,CRS, 56 $PASHQ,DFO, 131 $PASHQ,DIR, 56 $PASHQ,FL S, 59 $PASHQ,IDR, 150 $PASHQ,ION, 62 $PASHQ,MSG, 12
$PASHS,CACK, 55 $PASHS,CPD, OUT, 141 $PASHS,CPD,AFP, 133 $PASHS,CPD,ANT, 133 $PASHS,CPD,DYN, 135 $PASHS,CPD,ENT, 136 $PASHS,CPD,EOT, 136 $PASHS,CPD,FST, 137 $PASHS,CPD,MOD, 138 $PASHS,CPD,MTP, 140 $PASHS,CPD,PED, 142 $PASHS,CPD,PER, 141 $PASHS,CPD,POS, 142 $PASHS,CPD,PRT, 144 $PASHS,CPD,RST, 143 $PASHS,CPD,UBP, 146 $PASHS,DSC, 56 $PASHS,DSY, 57 $PASHS,ELM, 58 $PASHS,EPG, 58 $PASHS,FIL, 58 $PASHS,FIX, 59 $PASHS,HDP, 61 $PASHS,IDR, 149 $PASHS,INI, 61 $PASHS,ION, 62 $PASHS,LAT, 62 $PASHS,LON, 63 $PASHS,MSMOD,
$PASHSMNME,ALL,x,OFF, 95 Numerics 2-D, 52 2HZ option, 114 8N1, 13 A B BAS, 124 base, 129 position, 146 station, 128 bearing and distance, 97 BEN output, 83 binary, 83, 88 Index C carrier phase, 150 CAT IIIB aircraft landing, 1 CBN, 84 CBN message, 84 CFG, 55 Coarse/Acquisition, 1 COD, 124 communication link, 125 communication quality, 126 constellation, 2 corrections, 127 course over ground (COG), 121 CPD, 86, 137, 138, 144, 150 cross-track error (XTE), 121 CRS, 56 current antenna param eters, 54 epoch
differential, 125 base, 124 correction, 126 options, 129 remote, 126, 129 DIR, 56 DLK, 134 docking, 1 DOP, 104 DSC, 56 DSY, 57 DYN, 135 E elevation mask, 58 ellipsoidal height, 52 ELM, 58 ENT, 136 EOT, 125, 136 EPB, 88 EPG, 58 epoch, 58 epoch solutions, 84 event data, 56 marker, 117 external RAM, 140 H HDOP mask, 61 HDP, 61 headers, 43 Horizontal azimuth, 53, 133 Husky FS/2, 4 I F fast CPD, 137 FIL, 58 file directory, 56 information, 59 number, 58 first file, 56 FIX, 59 FLS, 59 FST, 137 Page Index-4 I
last altitude entered, 59 LAT, 62 latencies, 1 link speed, 71 LNA, 1 LON, 63 M N NAVSTAR, 2 NMEA, 88 almanac message, 98 autopilot, 96 GPS position, 99 latitude/longitude, 101 satellite range residual, 102 Q Q option, 4 QA value, 126 QAF, 126 quality factor, 126 O OBN, 86 OBN message, 85 OFF, 69, 95 options, 125 OUT, 141 output rate, 127 P packed, 150 packed data, 150 PAR, 63 PBN, 88 P-code, 82 Index Index Marine III, 4 maximum age, 123, 125 memory reset, 59 message types 18 and 19, 1 MOD, 138 most r
real-time, 152 data output, 87 kinematic, 1 output, 85 Real-Time Z™, 1 REC, 71 reference point, 53, 133, 141, 142 reference station, 128 REM, 126 remote, 125, 129 remote station, 131 REMOTE.EXE, 55 RF sensitivity, 71 RID, 71 RNG, 72 rover, 127, 135, 137, 140 RRE, 114, 115 RS-232, 3 RST, 72, 143 RTC, 152 RTCM, 3, 124, 125, 126, 128 Committee, 125 Differential, 125 Message 18/19, 125 message type, 110 reference, 109 remote, 124, 125 SC 104 V 2.
WGS, 133 WGS84, 53 X XTE, 121 Z Z mode, 82 ZMD, 82 Z-tracking™, 1 Index Index Page Index-7
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