|Quoting BackSeater (Reply 98):|
But more recently MarkAK supported by Mandal499 indicated that the satcom on MH370 removed the aircraft induced Doppler by pre-compensation. That is crucial because if confirmed, then the method I described in post #24 above may give us the approximate aircraft location on the RTD ring at each ping without assuming any speed or heading a priori!
|Quoting BackSeater (Reply 24):|
What the earth station will measure is the satellite Doppler vector projected onto the satellite to aircraft vector. The measured Doppler scalar value compared to the Doppler expected from the instantaneous speed of the satellite yields the angle between satellite speed vector and satellite to aircraft vector. That angle is the half angle of a cone whose axis is the satellite speed vector. That cone should mostly intersect the southern portion of the ring in one point unless the speed vector of the satellite happens to almost point to the aircraft. In that case we shall unfortunately have two intersections. But by looking at successive calculated locations, we should be able to eliminate one of the two intersections if any ever occurred during the construction process.
I don't fully understand your method explained in reply #24, especially as there is only "Doppler scalar" value (for example 300 Hz), not "Doppler vector". However as Inmarsat has stated that they can get no furher information regarding the aircraft position (besides selecting the southern arc) from the ping and Doppler, I assume that the calculation you suggest is not possible.