[time-nuts] KS problem

Charles Steinmetz csteinmetz at yandex.com
Wed Dec 10 17:42:34 EST 2014

Bob wrote:

>No, I do not have a 360 degree view of the sky   *  *  *   I have 
>the southerly 180 degrees from about 20 degrees elevation and up.  I 
>bought this KS as an example reference for my homegrown.  It may be 
>that it's just not up to the job under my conditions.

This will affect the ultimate performance of your GPSDO, too.  GPS 
engines are able to generate the best "solution" and, therefore, to 
produce the most stable PPS, when the available satellite 
constellation includes a geometric diversity of good signals (i.e., 
good signals from satellites everywhere in the skyward 
hemisphere).  A limited view of the sky causes a less stable PPS, 
which in turn causes a less stable GPSDO output.  Probably not a big 
factor at xDEV ~ e-10, but increasingly important if you push toward e-12.

Best regards,


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