Improved Galileo Time to First Fix - Bert Hubert's writings
a day ago
- Galileo introduced three new features to significantly reduce 'time to first fix' without needing cloud assistance.
- The new features include a lower-precision short-term orbit/clock message (word 16) for faster initial fixes.
- Parity protection using Reed-Solomon codes (words 17-20) allows recovery of full ephemeris from any 4 of 8 messages, improving robustness.
- A secondary synchronization pattern (SSP) tags each message with GST time modulo 6 seconds, aiding faster time synchronization even without decoding.
- These improvements provide resilience for unconnected devices and during communication disruptions, while also speeding up fixes for connected devices.