[time-nuts] GPS Sat Clock Data

Bob Camp lists at rtty.us
Thu Jun 3 22:10:56 EDT 2010


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
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