The head of aviation at the University of News South Wales, Professor Jason Middleton, helps explain just how these systems work and why there is no exact location for the plane.
A rough location can be extrapolated by measuring the time it takes for the ping to be picked up by two satellites.
To the best of my knowledge the Inmarsat I-3 series satellite at nominal position 0° 64°E had logged the unique ID of this aircraft when the SATCOM was activated prior to departure Lumpur. The Satellite checked hourly that the bird was still in range by 'pinging' it. The return time of the signal originated by the SAT and acknowledged by the aircraft is the means of creating a position line (in this case a curved one) that is being used to determine the radius of a circle on which the aircraft could be. This whole procedure has been explained in many posts to this thread, and the Professor should at least get his facts right.
The basic explanation can be found on -
page 297 Post #5935
and an example showing the possible 180°M heading is on -
page 299 Post #5971
The BBC seems to be reading PPRuNE, and its a pity the professor hasn't.
Only ONE satellite is involved.