[ntp:questions] Re: GPS signal quality

Brad Knowles brad at stop.mail-abuse.org
Wed Nov 10 19:22:11 UTC 2004

At 2:07 PM -0500 2004-11-10, Richard B. Gilbert wrote:

>  When GPS does work reliably; e.g. when you have a good quality signal from
>  four satellites, your clock can synchronize to within 40 microseconds or
>  better.

	This is why it can be extremely useful/important to use a GPS 
receiver that also includes an OXCO or other type of accurate clock 
that can be disciplined by the GPS signal, so that you can continue 
in a degraded mode while the GPS signal is not available and yet 
still have reasonably good time being delivered to your server.

	One example here would be the Meinberg unit.

Brad Knowles, <brad at stop.mail-abuse.org>

"Those who would give up essential Liberty, to purchase a little
temporary Safety, deserve neither Liberty nor Safety."

     -- Benjamin Franklin (1706-1790), reply of the Pennsylvania
     Assembly to the Governor, November 11, 1755

   SAGE member since 1995.  See <http://www.sage.org/> for more info.

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