"aviationweekEase with which GPS can be spoofed raises concerns about civil UAVs. A video fo a small unmanned heicopter dropping from hover like a stone, its operator unaware control has been hijacked, threatens plans to open civil airspace to UAS (unmanned aerial systems) by exposing the vulnerability of GPS to counterfeit signals, or spoofing."

Continue reading the Aviation Week and Space Technology article that features an interview with Dr. Humphreys.