[ntp:questions] First attempt GPSD/PPS ->NTP time server

David J Taylor david-taylor at blueyonder.neither-this-bit.nor-this-bit.co.uk
Fri Jan 25 08:20:23 UTC 2008


Dennis Hilberg, Jr. wrote:
[]
> The GPS time is not very accurate anyway, and can vary wildly,
> probably depending on the device, so don't expect perfect offsets. On my 
> Garmin GPS 18 LVC, I use 0.190 which gets it in the ballpark,
> but can randomly jump +16ms to -10ms at any time.

With a good view of the sky, the GPS time should be within a microsecond. 
The fact that you have a 0.2s offset suggests you are synching to the 
trailing edge of the PPS signal and not the leading edge.  Is that 
possible?  Have you checked the polarity, and the flag2 setting?

Cheers,
David 





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