[ntp:questions] how to have offset < 1ms

Richard B. Gilbert rgilbert88 at comcast.net
Wed Apr 14 02:27:45 UTC 2010

John Hasler wrote:
> Richard B. Gilbert writes:
>> With a closed network the options are limited.  With a place to site a
>> GPS antenna, you can install a GPS clock that will be accurate to
>> within +/- 50 nanoseconds.
> It occurs to me that the sort of fancy GPS that an oceanographic ship is
> sure to have on the bridge may already be capable of providing time
> service.

The possibility is certainly there.  I suspect that a great deal depends 
on how the GPS navigation system is designed.  It could, in principle, 
output any or all of latitude, longitude, elevation, and time.  On a 
ship the elevation will probably not be of great interest and will 
probably be omitted.  The time is almost certainly displayed.  Whether 
or not there is provision for distributing time to remote locations; 
e.g. passenger's cabins, is up to the designers and he who pays the bill!

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