[ntp:questions] NTP on red hat 7.3, was precision can be expected

Richard B. Gilbert rgilbert88 at comcast.net
Thu Jun 21 21:14:37 UTC 2007


Rejean wrote:
> I'm trying to use NTP 4.2.0 with red hat 7.3 and a military GPS on a
> Pentium 1.4 Ghz board.
> 
> If I compare the Linux Time with the GPS time using a oscilloscope.
> At start time I was getting a time difference of about 20ms then after
> 6h linux time was 150ms ahead.
> Can i expect to have a time precision to +/-20ms whithout the PPS.
> 

There's no way we can answer that without knowing more about the GPS and 
how time is being transmitted to the Linux system!

WITH the PPS, you should have time good to within 50 nanoseconds or 
better!  Just how good it will be depends very much on how the interrupt 
system works.  If it's low latency, time will be very good.  If not, not!





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