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| author | Eric S. Raymond <esr@thyrsus.com> | 2013-09-28 07:30:37 -0400 |
|---|---|---|
| committer | Eric S. Raymond <esr@thyrsus.com> | 2013-09-28 07:30:37 -0400 |
| commit | f695fa37b75c966659956ababe5cbd6584b38639 (patch) | |
| tree | 171c33ff3e3d98078dec3bab1f856711273096ec /timebase.c | |
| parent | 0fde30987d1893fcca4e1834c3a0694627757b47 (diff) | |
| download | gpsd-f695fa37b75c966659956ababe5cbd6584b38639.tar.gz | |
More about time constraints.
Diffstat (limited to 'timebase.c')
| -rw-r--r-- | timebase.c | 7 |
1 files changed, 6 insertions, 1 deletions
@@ -21,7 +21,12 @@ necessarily processed correctly on consumer-grade devices, and will not be available at all when a GPS receiver has just cold-booted. Thus, UTC time reported from NMEA devices may be slightly inaccurate between a cold boot or leap second and the following -subframe broadcast. +subframe broadcast. + +It might be best not to trust time for 20 minutes after GPSD startup +(long enough for an ephemeris to load) but this isn't actually +implemented as the divergence will normally be only one second or +less. GPS date and time are subject to a rollover problem in the 10-bit week number counter, which will re-zero every 1024 weeks (roughly every 20 |