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

[Ilia Platone]

If using this system can the relative positions of the telescopes be
calculated also? You said the delay corresponding with 1mm is about 1ps,
so during processing we'd calculate the relative positions also using
delays between the various stations, if using common-view pulses at a
different frequency also, positions would be adjusted later with such
precision.

Regards,
Ilia.

Il 11/04/2016 14:33, jimlux ha scritto:
> On 4/11/16 1:40 AM, Björn wrote:
>> Hi Bruce,
>>
>> For such short baselines single frequency GNSS should be able to keep
>> fixed integer solutions. Not sure how much money thas is going to
>> save, since you might need timing specific geodetic receivers to get
>> external 10MHz input.
>>
>> Did you consider implementing time transfer using time reversal using
>> say a sdr tranciever (usrp or other) where your clock is driving the
>> radio. As done on HF by Yen & Sengupta at last PTTI.
>>
>> https://www.ion.org/ptti/abstracts.cfm?paperID=3373
>>
>
>
> VLA used VHF (I think) radio links to provide common phase reference
> among apertures.
>
> Consider, for example, using a 1 GHz CW carrier among your stations.
> With good SNR, tracking phase to 1/1000th of a cycle should be
> straightforward.
>
> The challenge will be (as always with this kind of thing) the
> mechanical effects.  Motion of 1mm is 3ps.
>
> On the other hand, my victim detection radar trivially measures 1mm
> displacements in path length with 20 dB SNR with EIRP of 1 mW, omni
> antennas, and a range of 30m with a 0.1 square meter target.  That's
> at 3 GHz.
>
>
>
>
>
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*Ilia Platone
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