A commercial GPS Receiver and multiple antennas were mounted on a small Cessna airplane to perform local flight tests near Stanford in the early 1990’s. The tests showed that GPS could provide aviation attitude control for en route and precision approaches at the Palo Alto airport. The tests were broadened to include local terrestrial pseudolites transmitting a GPS signal, which allowed for successful automatic landing of the Cessna.
Shortly afterward the tests were broadened dramatically when the FAA provided a Boeing 737, which allowed fully automatic approach and blind landings tests in which 110 successful landings were performed. Extensive further testing was performed in other locations (Alaska, Tahoe, Atlantic City, etc.) using other aircraft.
Stanford originally received funding for this research from NASA and the FAA.