[ntp:questions] GPS

David L. Mills mills at udel.edu
Tue Oct 5 20:50:47 UTC 2010


My experience with SA some years ago was that the timing accuracy was in 
the order of LORAN C, that is, about one microsecond. However, the 
oscillator in my Austron 2201 GPS receiver was disciplined in frequency 
by LORAN C, with result the timing accuracy was in the order of 50 ns. I 
calibrated it with a Cesium oscillator. In other words, even if SA were 
turned back on, it is easily defeated.


John Hasler wrote:

>Chris H writes:
>>With Selective Availability enabled would that cause time accuracy
>>issues with the signals from the satellite?
>I believe that it would inject a maximum of about 300 ns of random
>error.  However, SA is obsolete.  The newest satellites don't even
>implement it.

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