How does the FAA think this is going to work after 2020 when air traffic control will run off of ADS-B positional telemetry from aircraft. It seems a GPS shutdown like this would basically shut down IFR flying and airport terminal control since ATC has no other way of knowing the position of airplanes.
> It seems a GPS shutdown like this would basically shut down IFR flying and airport terminal control since ATC has no other way of knowing the position of airplanes.
I highly doubt that good old-fashioned radar will be shut down. It has to be, anyway, for all the planes either that don't have the equipment for IFR, and the pilots which are not certified for IFR, only for VFR.
Modern Inertial Reference Units [0] (IRU/IRS/INS) are fitted to most airliners and business jets, and are an alternative to GPS. IRU accuracy is less than GPS, and older units have issues with drift.
The FAA hasn't approved any IRU for ADS-B[1] backup.
More importantly, ATC can use the Mode-S[2] transponder without GPS to locate the aircraft. Secondary Surveillance Radar won't be phased out in 2020. ADS-B will be required by the FAA in 2020.
