[time-nuts] Checking the Frequency of a Rubidium Oscillator

[WB6BNQ]

GEEZ,

After all this discussion, it sounds like he should consider 2 Cs space devices,
one main and a secondary.

Bill....WB6BNQ


Poul-Henning Kamp wrote:

> In message <491A210B.30401 at rubidium.dyndns.org>, Magnus Danielson writes:
>
> > Once doppler bin and phase has been achieved for each PRN, [...]
>
> Just a footnote to say that as soon as you start receiving ephemerides
> from the first sat, the search-space can be significantly reduced
> if you care to do the, rather longhaired, trignometric math.
>
> >A sat based receiver must handle higher doppler offsets due to its
> >higher speed, [...]
>
> While this is true for any non-geo-stationary satellite, it may not
> be true for the project the initial poster talked about.
>
> As I remember it, he said that the mission would be in an earth-following
> orbit, ie: in the same orbit as the earth around the sun, but
> trailing it by some distance.
>
> Given that the distance in GPS terms is "vast" and furthermore that
> the GPS orbits have a pretty steep angle relative to the earths
> orbital path, I would expect the doppler offsets to be much smaller
> than here on earth.
>
> Obviously, getting a position fix will suck with the worst
> DOP seen to date, but a frequency fix should not be out
> of the question.
>
> Obviously, the situation on the way to the final orbit is entirely
> different, and there I would expect doppler to be totally out
> of the lower end of the window.
>
> Remember to figure out the relevant relativistic corrections.
>
> Poul-Henning
>
> --
> Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
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