[ntp:questions] how to have offset < 1ms
unruh at wormhole.physics.ubc.ca
Mon Apr 12 22:48:30 UTC 2010
On 2010-04-12, lhommedumatch <ludocluba at yahoo.com> wrote:
> I'm working on a oceanographic vessel
> ntpgmtaceb is our reference clock that is synchronised with a gps at
> the beginning of a cruise.
Why not put a Garmin GPS 18 on board the ship and get gps time on the
But why are you getting 20ms roundtrip delay going from one onboard
computer to that computer. the ship is only say 100m long, which is at
best 1usec delay ( yes, I knwo the delay is dominated by the
switches/hubs along the way).
> The drift of this clock is <1ms each day.
> It's connected on the lan board of our vessel.
> I have removed these two lines
> server 127.127.1.0
> fudge 127.127.1.0 stratum 10
> service ntpd stop
> ntpdate ntpgmtaceb
> 12 Apr 21:46:22 ntpdate: adjust time server 192.168.21.5 offset
> service ntp start
> ntpq -p
> remote refid st t when poll reach delay
> offset jitter
> *ntpgmtaceb .1PPS. 1 u 20 64 377 0.144
> -0.373 0.863
That doe slook a lot better. I am not sure why the delay should be so
much different however.
> So it's seems to be really better, isn't it?
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