Originally Posted by
RetiredF4
@Hyperveloce
Excuse my ignorance, but are not all those theories concerning the Inmarsat Data analysis based on constant track, constant altitude and constant speed?
As far as I know, they are constant speed trajectories (Inmarsat's). You may also want to fit constant bearing trajectories or variable speed/bearing trajectories... The altitude variations (unless they are well beyond those of a controlled aircraft) do not seem to impact the doppler profile significantly.
Originally Posted by
RetiredF4
And the measurement only took place at one specific tenth of a second with a time gap of about 1 hour in between those plots?
Now if at that exact time of measurement (when the ping occurrred) the jet was maneuvering like turning away from the sat thus changing the doppler shift for only this specific time frame, would then your statement from before still hold ?
It is very much true that the underlying continuous doppler time serie has to be sampled at precise instants to see the doppler peak in the BFO... another way to put it: one the 3 consecutive handshakes around 18:30 in the BFO has to occur in a time frame of a few seconds (maybe not tenth of sec) centered on the moment when the speed vector is in the direction of the Inmarsat subsatellite. In my MonteCarlo simulations, this was the case for tens of simulated runs over a few thousands runs (a few percent probability)... This cannot be a coincidence, it would mean that the handshakes tended to occur when the flight conditions changed.
Originally Posted by
RetiredF4
At the end, we only have few pings which create distance rings from the sat plotted to the earth and a specific doppler shift asociated with those rings. But what happened in between those pings concernng height changes, speed changes and track changes is not known at all.
Could you explain, with what percentage those asumptions would be true?
That's true again, we know nothing between the handshakes and we have to make assumptions like trying to find/fit trajectories with minimal speed or bearing variations. Back to the percentages, certainly, the lowest probability goes to the relative timing between the jet virage/manoeuver (toward the south) time sequence and the handshakes instants... either the handshakes are designed to be initiated when flight conditions change or this is a huge coincidence (which seems to happen also earlier in the flight when the plane diverted from its route to Beijing).
Jeff