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

Rejean rsenecal at oerlikon.ca
Thu Jun 21 21:57:39 UTC 2007


On Jun 21, 5:14 pm, "Richard B. Gilbert" <rgilber... at comcast.net>
wrote:
> 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!

The GPS is connected through the serial port at 9600 bps
And the ntp.conf is setup to read it.

>
> 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!





More information about the questions mailing list