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Fix PPS based UTC timestamp in camera trigger and capture messages

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The existing implementation has about 100ms difference to a reference clock. With the changes this error less than 25us.
- Use sensor_gps messages with hrt timestamps as RTC reference and not the system realtime clock. The PPS interrupt can then be aligned with the GPS clock system.
- Keep fallback based on system RTC when no PPS pulse was captured
This commit is contained in:
Michael Schaeuble
2021-12-17 07:56:08 +01:00
committed by Beat Küng
parent ebb657bcf4
commit 5ad8b84dec
6 changed files with 61 additions and 31 deletions
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msg/pps_capture.msg
+2 -3
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@@ -1,3 +1,2 @@
uint64 timestamp # time since system start (microseconds)
uint64 rtc_timestamp # captured time in microseconds from real-time clock at PPS event
int32 rtc_drift_time # time drift between RTC and PPS event in microseconds
uint64 timestamp # time since system start (microseconds) at PPS capture event
uint64 rtc_timestamp # Corrected GPS UTC timestamp at PPS capture event