[ntp:questions] Accuracy of GPS satellite signal ?

Ry malayter at gmail.com
Sun Jan 28 14:54:35 UTC 2007

On Jan 28, 8:39 am, John Allen <allen{at}vo{dot}lu> wrote:
> Richard B. Gilbert wrote:
> > It should not matter which satellites your site is using, they all keep
> > the same time to within nanoseconds!To satisfy my curiosity without effort on my part, can someone tell me where the GPS
> satellites actually get their time from?
The atmoic clock on each sattelite is synchronized with the time from 
the U.S. Naval Observatory's atomic clocks. As for the "time exchange" 
protocol they use, I'm not sure, but I'd assume it is a lot more 
specialized (and most likely more complex) than NTP. I think they 
would have to account for radio propagation variations and 
relativistic effects at the very least.

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