[time-nuts] Timing Distribution in Mountainous Terrain

[Bob Camp]

Hi

Satellites appear to be out. Best case, pulsars would be a once a day thing. You would need a bit better than 30 ns on the transfer (10?) to get the system to perform.

To put an order of magnitude on the difficulty:

I believe that 20 ns is in the same range as the error national standards labs hold relative to UTC.  

http://tf.nist.gov/pubs/bulletin/nistusnoarchive2009.htm 

That's with a lot more effort than any rational system is going to put into timing. Also that's with GPS available to allow precision time transfer. 

Bob



On Sep 10, 2010, at 5:15 AM, Peter Monta <pmonta at gmail.com> wrote:

>> Aren't pulsars a reliable accurate time source or do they not provide the 30nS over ten days accuracy?
> 
> By using them in common view, though, any absolute error would drop
> out.  I'm not sure pulsar pulses are fast enough to do discrimination
> at 30 ns time scales, though.  VLBI with broadband sources (quasars)
> would be fine here, but large amounts of data would need to be
> exchanged, and the sources are weak, requiring large antennas.
> 
> Satellite laser ranging using LAGEOS and friends?  But the original
> poster said no satellites (not even passive rocks in MEO?), and
> weather is a problem.
> 
> Cheers,
> Peter Monta
> 
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