[ntp:questions] Slow convergence of NTP with GPS/PPS
david at ex.djwhome.demon.co.uk.invalid
Thu Oct 23 22:21:30 UTC 2008
> Assuming the network noise is the 100us level, (which it is for example
> between me and Regina 3000km away) you should get the accuracy easily to
> 1ms in 1 sec. if all you want is the phase error. One packet exchange will
> give it to you.
You have an unused network. For about 20km between work and ISP it is
more like 100ms peak to peak. (2Mb/s 1:1)
> receiver would be better, especially if it know its location. Then within
> seconds it would know the time to nanoseconds. If it has to diiscover its
It's going to take at least 30 seconds to do that, as it will need the
detailed emphemeris data and that takes 30 seconds to transmit (it might
well pick the strongest signal and try to read the coarse ephemeris data
first; I'm not sure if that fits in the 30 seconds.
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