Novatel OM-20000053 Rev 2 1.3 DIFFERENTIAL OPERATION

1 Quick Start
16 MiLLennium GPSCard SW Version 4.503/4.52 Command Descriptions Manual Rev 2
COMMONLY USED LOGS
Other useful logs are
•RCCA to list the default command settings
•ETSA to monitor the channel tracking status
•SATA to observe 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 information on sending commands see Chapter
2, Page 24 and the individual commands listed alphabetically in Appendix C, Page 81.
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 anticipated data link and remote users. Use the GPSCard COMn command 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.
Type Logs Trigger
Positioning PRTKA/B
POSA/B ontime or onmark
Post Processing RGEA/B/D
REPA/B, ALMA/B ontime onchanged
NMEA Position GPGLL
GPGGA ontime or onmark