Its obvious to me that the aircraft is "pinging home" sending packets of data back to a control centre, where they get distributed to various people depending on what they are and who subscribe to them.
But since MAS did not subscribe, now the burden is on Inmarsat to do telecom forensics based on the little they may have received, but never relayed.
I think that no location data is included in the pings and even if it was it would not be decoded on sat, so they will have to work with just signal analysis, not even exact triangulation, as someone explained before, from that the "corridors" notion.