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

Chris Albertson albertson.chris at gmail.com
Tue Jul 12 20:21:03 UTC 2011

On Tue, Jul 12, 2011 at 12:06 PM, Michael Eder <meder at whoi.edu> wrote:
> We are using a Garmin GPS 16x.  I should clarify these are platforms in the
> middle of the ocean so the sole time source is the GPS and PPS.

Ok, then your requirements are modest.  Typically when you see someone
using GPS he is setting up some servers for a lab or campus.  In that
case just get a better GPS.  New units with prices under $100 work at
the nano second level while Garmin nav GPSes are microsecond devices
at best but with the serial data (as you have found)  notoriously not
well synchronized.

But for your purpose even the 16x is orders of magnitude better then
you really need.   Opening up the tolerance makes senses on a buoy.
You could not even use one of the better timing GPS on a buoy because
they require a fixed location antenna.

You can reduce the problem with the nmea data by turning off unneeded
sentences if you have not already done so.

Chris Albertson
Redondo Beach, California

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