It also has an option to sync the PPS with GPS or UTC. I thought they were off by an integral number of seconds so I don't expect any change. Does anybody know what's going on here?
The GPS broadcast message includes leap second and a0 and a1 terms which are used to forward predict UTC from GPS time, which is derived from UTC(USNO).
A0 and A1 are what you'd guess: a phase offset and a frequency offset. See page 157 of the GPS ICD: <http://www.navcen.uscg.gov/gps/geninfo/ICD-GPS-200C%20with%20IRNs%2012345.pdf> So yes, at the ns level the two 1PPS will differ since UTC is not the same as UTC(USNO) or any other UTC(k) for that matter. Have you measured it? I would be interested to know what the delta is for your receiver today. You can also dump out the a1 and a0 corrections with binary commands on some GPS receivers. /tvb _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
