4 Data Logs

26 MiLLennium Command Descriptions Manual

4.5 GPS TIME VS LOCAL RECEIVER TIME
All logs report GPS time expressed in GPS weeks and seconds into the week. The time reported is not corrected for
local receiver clock error. To derive the closest GPS time, one must subtract the clock offset shown in the CLKA log
(field 4) from GPS time reported.
GPS time is based on an atomic time scale. Universal Time Coordinated (UTC) time (reported in NMEA logs) is also
based on an atomic time scale, with an offset of seconds applied to coordinate Universal Time to GPS time. GPS
time is designated as being coincident with UTC at the start date of January 6, 1980 (00 hours). GPS time does not
count leap seconds, and therefore an offset exists between UTC and GPS time (at this date: 10 seconds). The GPS
week consists of 604800 seconds, where 000000 seconds is at Saturday midnight. Each week at this time, the week
number increments by one, and the seconds into the week resets to 0. (See Appendix H, Some Common Unit
Conversions, for an example)
4.6 LOG TABLES
Table 4-1 lists the logs by function while Table 4-2 is an alphabetical listing of logs. Please see Appendix D for a
more detailed description of individual NovAtel and NMEA format logs which are listed alphabetically. RTCM
and RTCA format data logs can be found in Chapter 6, Message Formats while receiver-independant RINEX logs
will be found in Chapter 7. Special Pass-Through logs are found in the next chapter, Chapter 5.

Table 4-1 Logs By Function Table

COMMUNICATIONS, CONTROL AND STATUS
Logs Descriptions
CDSA/B COM port communications status
COM1A/B Log data from COM1
COM2A/B Log data from COM2
COMnA/B Pass-through data logs
RCSA/B Receiver self-test status
RTCM16T NovAtel ASCII format special message
RTCM16 RTCM format special message
GENERAL RECEIVER CONTROL AND STATUS
Logs Descriptions
PVAA/B Receiver’s latest computed position, velocity and acceleration in ECEF coordinates
RCCA Receiver configuration status
RCSA/B Version and self-test status
RVSA/B Receiver status
VERA/B Receiver hardware and software version numbers
POSITION, PARAMETERS, AND SOLUTION FILTERING CONTROL
Logs Descriptions
DOPA/B DOP of SVs currently tracking
GGAB GPS fix data
GPGGA NMEA, position data
GPGLL NMEA, position data
GPGRS NMEA, range residuals
GPGSA NMEA, DOP information
GPGST NMEA, measurement noise statistics
MKPA/B Position at time of mark
POSA/B Position data
PRTKA/B Computed position
PXYA/B Position (Cartesian x,y,z coordinates)
RTKA/B Computed position
SPHA/B Speed and direction over ground