Back in the 90's, GPS was purposely degraded for ask but the US Military. I was in an Army Aviation unit, and I remember having to load what we called “anti-spoofing” codes into the GPS to allow the system to correct for this degradation and provide the high accuracy positional data we expect today.

These types of testing activities occur a lot more often and in a lot more places around the US than you may think. Anywhere there is a US government technology development site (Aberdeen Proving Grounds, Dahlgren Naval Research, Patuxent River Navel Air Station, Wright-Patterson AFB, etc.) you can be sure to see some…