Dear Bob and Zach,
This paper might be worth looking at: http://www.dtic.mil/dtic/tr/fulltext/u2/409103.pdf
As far as I know, it started the whole business of location by measurement of Doppler shift.
Apparently, according to the success of project Transit, it is possible to:
a) Compute the TLEs of a satellite by using just a few minutes of the Doppler curve of the beacon of a satellite, as received on a ground station with known location.
b) Compute the location of a ground station, by using just a few minutes of the Doppler curve of the beacon of a satellite with known TLEs, as received on said ground station.
Of course, several variation on this are possible, such as the one which is discussed here:
Compute the location of a ground station by using the Doppler curve of its transmissions during a pass, as received on a satellite with known TLEs.
It seems that the key point in all this is that the Doopler curve depends independently on all the parameters in question (so not a cubic polynomial, which depends on fewer parameters).
73,
Dani M0HXM/EA4GPZ.
El 09/11/15 a las 17:59, Zach Leffke escribió:
No worries, I thought on it a bit more and I think a cubic polynomial is the right fit. I also found some python tools for regression calculations that I think will be useful for this. Also, I think this is pretty similar to how the COSPAS/SARSAT system used to locate lost ships (EPIRBs) and downed Aircraft (ELTs) before the proliferation of GPS and its inclusion in the locator beacons.