[time-nuts] Timing or Navigation GPS Receivers (was: Turning offPPS when not enough satellites)

[Tom Van Baak]

> It's interesting that the now in development carrier phase GPS time
> transfer method that might offer 1,000 times lower uncertanity is based
> on the Ashtech Z12 surveying receiver, not a timing specific GPS receiver.

These are Z12-T receivers, an expensive upgrade to
the standard dual-frequency Ashtech Z12 receiver.

They require a high-performance (typically cesium or
H-maser) 20 MHz frequency as input. The 1PPS can
be used directly, but usually one just collects pseudo
range data from them and that data is post-processed
(up to two weeks, I think) by various geodetic services
with clock and orbit corrections. DougH can provide
more info on this (now obsolete) receiver. I had a Z12T
too but it died on me last year.

/tvb