[ntp:questions] Single GPS/PPS time source gets marked as afalseticker

David J Taylor david-taylor at blueyonder.co.uk.invalid
Fri Jul 15 08:56:20 UTC 2011

"Michael Eder" <meder at whoi.edu> wrote in message 
> Hi Folks,
> For our buoy deployments we have GPS and a highly accurate oscillator
> conditioned by the GPS PPS.  Unfortunately when we let this run for 
> longer
> periods we see both the GPS and PPS being marked as false tickers. 
> There is
> a lot of information on the web about this, but I have not found a
> definitive solution.  What is the best way to configure NTP when you 
> only
> have a GPS NMEA string and pulse per second?   In our situation it is
> feasible that the NMEA may not be always be available while the PPS is, 
> we
> are seeing a problem when both the NMEA and pulse seem to be working
> properly.
> Thanks in advance,
> Kind Regards,
> Michael Eder

Suggestion is to be sure that you have the latest firmware for the 
devices, particularly if they are Garmin ones.  We have spent the last few 
months investigating the issues of the serial NMEA data being late at 
times, and Garmin have now fixed this at least for the GPS 18x LVC series 
of devices.


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