How does Star Sync get the time from the GPS?
The GPS receiver outputs UTC (Coordinated Universal Time) date and time of day in the transmitted data. After the initial position fix, the date and time of day are calculated using GPS satellite information and are synchronized with the one-pulse-per-second output. The highly accurate one-pulse-per second output is provided to Star Sync from the Garmin GPS35. The signal is generated after the initial position fix has been calculated and continues until power down. This rising edge of the signal is synchronized to the the start of each GPS second. The information transmitted to Star Sync is referenced to the pulse immediately preceding the NMEA 0183 RMC sentence. Beagle Software specially configures the Garmin GPS35 so that this pulse is usable by the Star Sync software.
