[ntp:questions] Sure gps looses all sattelite fixes

Chris Albertson albertson.chris at gmail.com
Tue Feb 28 03:17:20 UTC 2012

On Mon, Feb 27, 2012 at 4:29 PM, John Hasler <jhasler at newsguy.com> wrote:

>> I could imagine that the signal is too weak for timing but strong
>> enough to get location info from the sattelite.

It works the other way around.  You need four satellites to get
location but once you know your location only one is needed for time.
(This assumes the sure GPS has a timing mode where you set a fixed
location.  All timing GPSes have this.)   The other thing is that GPS
satellites only send and time their orbital elements.  They leave it
to the receiver to use that to compute the satellite's location.   So
as the signal got worse and worse the last thing you'd loose is the
ability to keep time.

Chris Albertson
Redondo Beach, California

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