Commercial Flights Are Experiencing ‘Unthinkable’ GPS Attacks and Nobody Knows What to Do::New “spoofing” attacks resulting in total navigation failure have been occurring above the Middle East for months, which is “highly significant” for airline safety.
In the cell phone there are specialized chips that “just” read the signal. They use some interesting tricks to catch the timing right, but can’t be used to produce such a signal. The satellite “just” sends a signal with it’s own position and the timecode (based on it’s own atomic clock). And those nanoseconds and picoseconds of difference when the signals from different satellites arrive determine the distance to those satellites, and together with their position, one can calculate the receivers location.