[ntp:questions] best gps receiver for time synchronization

Richard B. Gilbert rgilbert88 at comcast.net
Mon Mar 9 21:45:04 UTC 2009

Augustine wrote:
> On Mar 9, 4:23 pm, "Richard B. Gilbert" <rgilber... at comcast.net>
> wrote:
>> 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

More information about the questions mailing list