Hi Bob, I have in the past watched presentations at ION on "signal in space" (SIS) accuracy for the GPS constellation. There was a steady improvement, with leaps between different SV (clock) generations. But also an improvements with adjustments in the ground segment, including adding more ground monitor sites. I am pretty sure there was also AVAR(?) plots for individual SVs maybe only clock types. One of the presentations was from Lookheed Martin where the new data was from II-RMs.
http://www.ion.org/search/search_proceedings.cfm -- Björn > Hi > > That's pretty close to what I'm looking for. The ideal would be to have > variance vs a range of tau for each individual sat. If there's a way to > get that from the NIST site, I've overlooked it. The "whole constellation" > data vs a range of tau is a reasonable starting point. The thing I was > surprised by was the range of performance of each sat as shown in the > paper I mentioned. > > Thanks! > > Bob > > > On Jun 3, 2010, at 9:54 PM, Brian Kirby wrote: > >> I do not know if this is what your looking for, >> http://www.nist.gov/physlab/div847/grp40/gpsarchive.cfm >> >> follow the directions on the date.... >> >> You can look at individual SVN performance, etc. >> >> Bob Camp wrote: >>> Hi >>> In this paper: >>> TOTAL HADAMARD VARIANCE: APPLICATION TO CLOCK STEERING BY KALMAN >>> FILTERING by Dave Howe , Ron Beard , Chuck Greenhall , Franc ̧ois >>> Vernotte and Bill Riley >>> http://tf.nist.gov/general/pdf/1459.pdf >>> Figure 2 actually refers to: >>> Navstar Quarterly Report 00-3, Space Application Branch, NRL, Wash D.C. >>> 20 July 2000. >>> The report apparently describes the level of variance on the various >>> GPS satellites versus tau for the first half of 2000. Bottom line >>> appears to be that 5x10^-13 is about as good as it gets out to 20 day >>> tau unless you can pick your sats. Obviously this data is a bit dated. >>> Is this data updated on a regular basis? Is it published somewhere? >>> Can one get a look at it without risking a long term stay in Federal >>> prison? It certainly would be useful to those trying to tweak GPSDO's. >>> Bob >>> _______________________________________________ >>> time-nuts mailing list -- [email protected] >>> To unsubscribe, go to >>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >> >> _______________________________________________ >> time-nuts mailing list -- [email protected] >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
