[time-nuts] Precise Time transfer and relative position over a short baseline

Bob Camp kb8tq at n1k.org
Mon Apr 11 07:34:13 EDT 2016


Hi


Is there a “common view” to a TV station or an FM radio station or a cell tower or ….

Carrier phase works on terrestrial signals. If you have one with a stable enough career and
a complex enough modulation to work out which cycle is which, it might be a cheaper approach.
 

Bob

> On Apr 11, 2016, at 1:00 AM, Bruce Griffiths <bruce.griffiths at xtra.co.nz> wrote:
> 
> There is a proposal to use multiple light bucket style optical telescopes to do Intensity stellar Interferometry over short baselines (up to perhaps 1km  or so) by using independent clocks to time tag photon  arrivals. store the time tags and process the data off line. Depending on the time tag resolution there is a need to measure the time differences between the independent clocks to an accuracy in the 1ns to 100ps range. Is there a better way of doing this other than using geodetic grade GPS receivers capable of GPS carrier phase measurements?Since the local clock flywheel oscillators will need to not deviate by more than 100ps or so over the several minutes required to perform the carrier phase averaging what sort of clock will be suitable apart from a good rubidium standard with a cleanup oscillator?
> NB Running fibres or coax between the telescopes isnt an option.
> 
> The relative positions of the telescopes has to be known to within a cm or so for this to work.
> Bruce
> 
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