Pings
Thanks garage. I'll try to find it.
The reason for asking is that if the identity being pinged relates to the engine numbers (say for onward data transmission to Rolls Royce), rather than the airframe number, it would still be be necessary for Inmarsat to link those engines to the plane. As many know, airlines frequently swap engines around.
However, I'm guessing they thought of that or, more likely, that the pings are identifying the airframe itself.
At a minimum, the Inmarsat device itself is uniquely identifiable on the network.
Think of it as having a Sim Card - many do.
As I mentioned above, many Inmarsat antennas contain a GPS, so no additional information from the airframe or the engine is needed to identify and locate the aircraft.
The "handshake" between the sat device and the satellite can contain a unique identifier, and its location.