[ntp:questions] Accuracy of NTP - Advice Needed

John Hasler jhasler at newsguy.com
Sat Dec 24 19:02:28 UTC 2011

unruh writes:
> They require ns accuracy in the timing and m accuracy in the
> distance. And the timing is not simply gps ( although they could have
> gotten that wrong) but then that timing has to be brought down into
> the mine a km or so below ground and horizontally and that also has to
> be surveyed for the distance.

The NOvA detector is not in a mine so it should be possible to site the
GPS receiver directly above it and drop a cable straight down.  The same
should be possible at the Fermi end.  You could set up both timing
chains at Fermilab (using indentical components including cable lengths
if you want to be fanatical), calibrate them against each other for
delay from antenna to output, and then pack one up and ship it up north
(of course there may be good reasons not to do it this way).  The
surveying should be easier than in Europe: there's no mountain range in
the way.
John Hasler 
jhasler at newsguy.com
Dancing Horse Hill
Elmwood, WI USA

More information about the questions mailing list