Hi,
I am using a microcontroller to generate PPS and NMEA string to time sync an Nvidia Jetson computer using gpsd and chrony for the GPS-denied environment. PPS and NMEA are verified as good.
When I started time synchronization process, chrony always like:
#* PPS 0 0 1 0 -894ms[ -894ms] +/- 1000ns
I tried a lot of times, chrony always considers PPS time is ahead around 890 ms. But I checked the NMEA time data is right. When the computer is synchronized, system time is ahead of NMEA time. Before the time synchronization, both of them are verified the same.
After the 1 hour test, time is synchronized, but with this const offset.
Could you tell me how to debug this? Thanks for your help..
Best regards,
-------------------------------------------------Lin Zhao
Research Assistant @ Graduate School of Oceanography
Ph.D. Student @ Department of Ocean Engineering
University of Rhode Island
Room 2, Horn Lab
215 South Ferry Road
Narragansett RI 02882
Phone: 401-771-4661