On Sep 30, 2011, at 6:45 PM, Tom Van Baak wrote: >>> And the clocks are not locked to a receiver, they are free but the offset >>> is continuously monitored through those CV measurement. >> >> Would you not lock the GPS (GNSS) receivers to the CS-clocks being compared? >> >> Björn > > It's pretty common with high-performance timing to NOT lock the > local clock to GPS. There are several reasons for this. One is that > you get the both the best stability of the undisturbed local clock > plus a continuous log of the difference between the local clock > and the external timing source (GPS). Locking an oscillator to > GPS introduces its own set of noise. Locking implies real-time > processing of the GPS signal (you miss a lot of performance > that way). > > The other reason is that they are at least using common view, if > not other forms of post-processing, to greatly improve accuracy. > There's always a trade-off between good GPS timing in real time > or superb GPS timing if you wait days or weeks and crunch all > the numbers.
It is a lot easier to post-process the data if there's no third party changing the frequency behind the scenes to keep things on time and on frequency. Warner _______________________________________________ LEAPSECS mailing list [email protected] http://six.pairlist.net/mailman/listinfo/leapsecs
