Wish I mod points. This is the crux of the entire problem. These satellite downlink frequencies were originally setup by the FCC for only that use. Now that the FCC messed up and allowed this to proceed we have a completely different ballgame - satellite downlink frequencies being transmitted at terrestrial locations and high power levels, but the existing receiving equipment (some 10-15 years old), is supposed to continue to work in an environment like this?
Existing receivers do not expect that kind of high power/close neighbor interfence because A> to have to filter it would reduce the received signal and sensitivity anyway (lower performance), B> any such filtering would be more expensive (power and cost), C> no filtering is required since the FCC already made sure no one would be swamping the signal by effectively keeping this area of spectrum "quiet" (or at least the received signals are all at similar power levels with sufficient guard bands).
There are other frequencies and better receivers, but these are not your cheapo handheld battery powered GPS receivers. So while technical solutions might be found going forward, the real problem is that most of the commercial GPS equipment will basically stop working - so who should pay to replace everyone's GPS (from handheld's, to in car units, iPhone's, etc)??