September 2021: The FAA authorized the MITRE Corporation to perform a series of tests that used commercial smartphones inside of aircraft as a method to detect GPS spoofing. These tests involved a feature of wireless cellular networks called Timing Advance that is available through standard 4G and 5G wireless networks operated by AT&T, T-Mobile and Verizon. A range estimate can be deduced from the basestations, which serves as a check for the GPS solution. GNSS spoofing expert Dr. Humphreys mentions that this technology is what he would hope the FAA would look at, as it could be an effective way to detect spoofing at a cheap cost.
