@Shadoko
Could be that the frequency (from the a/c) is corrected to zero Doppler (from true frequency received and internal clock), and Inmarsat made the measured from the length of the bits of data (lower "frequency" > lower Doppler)? Perhaps a stupid guess...
I don't think it's a stupid guess at all.
A while back in the thread there was an excellent post explaining the nature of the satellite/aircraft handshake (the "ping"). This included a requirement for the aircraft equipment to Doppler correct its transmission to the satellite.
That being so, it's also possible that Inmarsat may have done some of its analysis not based purely on the straightforward Doppler effect between aircraft and satellite, but on the residuals left after that correction took place, whether in terms of uncorrected shift or some other consequent effect.
It's also noteworthy that Inmarsat were at pains to state that they had calibrated their work against other southbound Malaysian B777 flights. The specificity of that statement implies that such a calibration may not have been valid if done against a flight by another carrier, or by another aircraft type. Or, indeed, on another routing. Perhaps the work relies, in part at least, on the specifics of the performance of the particular equipment build installed in MAS B777s??
If so, then attempts to reconstruct what Inmarsat have done based purely on the freshman physics of the Doppler effect and basic orbital mechanics are doomed to failure.
As for why Inmarsat haven't released the full details of what they have done, a few potential explanations come immediately to mind:
- It's just too complicated for ready public consumption . These are press releases, not technical papers, after all. The Doppler effect and geostationary orbits are pushing at the limits of public understanding as it is. I am sure that those who need to know have been given full briefings.
- If their work relies on the specific performance of the equipment build installed on the aircraft, then divulging details could well compromise the commercial confidentiality of the equipment supplier.
- If this really is "cutting edge" science (a description that doesn't exactly apply to orbital motions and the Doppler effect, after all!), then they may see commercial opportunities for what they've done and want to protect their interests before making a full, public disclosure.
Just a few thoughts...
