Special case of terrestrial positioning

Limitations in use or performance in all the above applications arise from signal reception difficulties:

• absorption: reducing the power of the received signal,

• obstruction: cancelling the signal and interrupting phase tracking,

• reflections: phase creating interference and distorting the measurement,

• radioelectric interference: producing local jammers and degrading the signal.

The presence and importance of these phenomena for the signal depend on the receiver's immediate environment. It's easy to see that the "terrestrial environment" is all the more difficult in this respect when you're...