fix(ubx): real UTC time and no fake sample timestamp on NAV-RELPOSNED/DAHEADING - #240
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dakejahl wants to merge 1 commit into
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fix(ubx): real UTC time and no fake sample timestamp on NAV-RELPOSNED/DAHEADING#240dakejahl wants to merge 1 commit into
dakejahl wants to merge 1 commit into
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…/DAHEADING time_utc_usec carried the raw iTOW, which is GPS time of week rather than a UTC epoch, so a consumer aligning the relative position to a PPS pulse got a time off by weeks. The UTC time is now derived from the last NAV-PVT/TIMEUTC epoch with a valid time by the iTOW difference; GPS and UTC differ by whole seconds, so the sub-week offset is identical in both. timestamp_sample was stamped with the parse time, which reads as a driver-supplied measurement time and defeated the consumer's receiver delay compensation. It is now left unset.
ABI/API Compatibility ReportStatus: DetailsThis comment is automatically updated on each push. |
dakejahl
marked this pull request as draft
September 10, 2026 04:25
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Summary
NAV-RELPOSNED and NAV-DAHEADING get a real
time_utc_usecand no longer stamptimestamp_samplewith the parse time.Problem
time_utc_useccarried the raw iTOW, GPS time of week rather than a UTC epoch, so a consumer aligning the relative position to a PPS pulse got a time off by weeks.timestamp_samplewas set to the parse time, which reads as a driver-supplied measurement time and defeats the consumer's receiver delay compensation. The PX4 side of this is PX4/PX4-Autopilot#27102.Solution
The UTC time is derived from the last NAV-PVT or NAV-TIMEUTC epoch with a valid time by the iTOW difference, wrapped at the week boundary. GPS and UTC differ by a whole number of seconds, so the sub-week offset is identical in both.
timestamp_sampleis left unset for the consumer to fill.