[ntp:questions] best gps receiver for time synchronization
Richard B. Gilbert
rgilbert88 at comcast.net
Mon Mar 9 21:45:04 UTC 2009
> On Mar 9, 4:23 pm, "Richard B. Gilbert" <rgilber... at comcast.net>
>> Just about any GPS timing receiver is accurate to within about 50
>> nanoseconds using the PPS signal.
> Just wondering, does one need to consider the delay that the signal
> takes to reach the receiver from the satellite?
There are FOUR satellites involved. The receiver solves a system of
four simultaneous equations in four unknowns to obtain: latitude,
longitude, elevation, and time. Timing receivers are frequently able to
"lock in" the location and these can get along with a single satellite
once they have determined their location.
Since there are usually seven to nine satellites visible, some timing
receivers use something called TRAIM to cross check. See; e.g. the
manual for the Motorola Oncore M12+T for the sordid details
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