GPS Dual receiver
- Dual Receiver is recommended for highest requests for time reliability such:
- Airports control centers, where Error higher than 5ms is total critical.
- Power plants
- Banking apps.
- Mounted are two GPS chipsets with ceramic antennas.
- These two chipsets are from different manufacturers and with different technology also:
- FASTRAX chipset
- SirfStart IV
- On board Supervisor processor:
- compare DATA from receivers
- compare PPS signal timing
only on valid conditions, supervisor produce output NMEA sentences with Time FIX VALID flag.
- What is valid conditions:
- Timing of Rising Edge of PPS pulses from receivers must be equal +/- 2 msec
- NMEA data must be equal to 1 second
- NMEA data must be received by Supervisor min 100 msec before Rising edge of PPS
Otherwise Supervisor produce NMEA sentence with NO FIX flag.
- We note: All NTP servers build-in (RTC) Real Time Clock is powered by thermal compensated Crystal, with max Error +/-1sec per week. RTC is adjusted only when GPS Time is different more than +/- 1 msec.
- All conditions: as cable, power ... are same as single receiver. Therefore replacement is simply available.