OleOle,
I understand the "satelite ping" thing as the iridium/inmarsat equipment of MH370 logging in to the iridum/inmarsat network. So it seems the backlogs of the network have been evaluated. I don't know how precise the position of the iridium/inmarsat transceiver can be infered from those logs.
I have no idea what satellite assets are used for the aircraft maintenance comms: Iridium, Inmarsat or something else. However, if Iridium is involved, then the satellites locate the terminal (modem) to within
about 10km E-W and 1km N-S. The asymmetry has to do with orbits or antenna patterns or something. Iridium was once able to tell us to about this accuracy where to find one of our assets, and, sure enough, it was within or near to those parameters.