In article <20110112162440.ab9f81c...@ptavv.es.net>, "Kevin Oberman" <ober...@es.net> writes:
>GPS satellites broadcast time in TAI, not UTC. Currently the offset >between TAI and UTC is 15 seconds. Actually, they broadcast GPS time which is offset from TAI by the number of leap seconds that had already happened when they started using GPS time. They also include the offset from GPS time to UTC so you can get UTC from GPS satellites. (They also include leap second warnings so you can do the right thing when leap seconds happen.) From http://tycho.usno.navy.mil/leapsec.html As of 1 January 2006, TAI is ahead of UTC by 33 seconds. TAI is ahead of GPS by 19 seconds. GPS is ahead of UTC by 14 seconds. We've had one more leap second since 2006, so that would be 34 and 15. http://maia.usno.navy.mil/ser7/tai-utc.dat 1999 JAN 1 =JD 2451179.5 TAI-UTC= 32.0 S + (MJD - 41317.) X 0.0 S 2006 JAN 1 =JD 2453736.5 TAI-UTC= 33.0 S + (MJD - 41317.) X 0.0 S 2009 JAN 1 =JD 2454832.5 TAI-UTC= 34.0 S + (MJD - 41317.) X 0.0 S -- These are my opinions, not necessarily my employer's. I hate spam. _______________________________________________ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
