Is sub-millisecond GPS time recorded or exposed on HERO13

[DrordeHartog]

Question:
On HERO13, is any sub-millisecond GPS timing (e.g., PPS edge timestamps or GPS–camera clock phase) recorded internally, even if it is not exposed via GPS9 or the current GPMF tooling?

Put differently: is the millisecond-level resolution observed in GPS9 a limitation of what is recorded, or only of what is exposed?

Context:
We are evaluating whether GPS time alone can serve as a shared timebase for sub-millisecond rolling-shutter phase comparison across two cameras, or whether an external PPS-visible optical event is fundamentally required.

Thanks in advance for any clarification

[dnewman-gpsw]

This will be require your own validation, but I don't expect it will meet you needs (not sub-millisecond.) Currently UTC time clock is to the nearest 0.1s, yet GPS9 allows for millisecond precision. Sometimes you will see 0.099 timing, which is odd. My two speculations:

1. GPS 10Hz output synchronous to the clock it is resolving, so you could use the GPMF timestamps to get higher precision (better that 0.1s) for time.
2. There is an artificial limit from the GPS chip vendor, GoPro would have to pay more for different microcode. This chip can be licensed for different applications and precision, it is doubtful GoPro would have paid extra (already costly to add GPS in every camera) for highest precision timing (location is more important.)
   or a combination of both.

[DrordeHartog]

Thanks for the quick and clear response