Markus Kuhn schrieb:
"Joseph S. Myers" wrote on 1999-12-04 12:14 UTC:
Do you happen to know what GPS receivers are available that provide user access to TAI (or some other form of the leap second offset information transmitted in GPS; ideally all the parameters from Table 2-11 (UTC Parameters) of the GPS Standard Positioning Service Signal Specification 2nd Edition)? This doesn't seem to be the sort of feature manufacturers of GPS receivers advertise, but it's of more interest to me in a GPS receiver than the route storage features that get promoted.
It is possible to extract TAI from GPS time. Those scales differ just by an integral amount of seconds. As for GPS to UTC conversion, the GPS has correction information that give the current and the future GPS/UTC offset and the time when the switch occurs. Thus leap second announcement can be calculated when approching a switch event. New ntpd code (4.0.x) support Trimble TSIP decoding. Newer Meinberg GPS receivers feature a binary protocol that will give out some more information, though no direct GPS time. GPS time can be reconstructed by converting the Meinberg time stamps to GPS via the GPS/UTC correction value. Regards, Frank Kardel