* Actual information is derived from phase shift between signals, not their contents * Signals are below noise level, you need to know their exact contents to

* Actual information is derived from phase shift between signals, not their contents * Signals are below noise level, you need to know their exact contents to be able to receive them * Military modification is encrypted, and it can help against some sorts of spoofing. * To spoof, you need to - receive signals from at least 4 sats (e.g. using a 2d phased array you can get pretty good directional sensitivity without knowing the contents of the signal). - retransmit the signals to the target, time-shifting each signal to achieve the required time+coordinate spoofing delta. - jam the original signals with a known noise source you can subtract from your own received signal to avoid jamming yourself ;)