Though the US denies Iran’s downing of a drone today, last December “Iran gained possession of a US stealth drone spying on a nuclear site. An Iranian engineer told the Monitor that Iran had hijacked the drone by manipulating its global positioning system coordinates, making it land in Iran,” according to The Monitor’s Scott Peterson. The NY Times notes that the US contends the RQ-170 drone crashed in Iranian territory last year.
Mr. Peterson, who broke the story on Iran’s success bringing down last year’s Stealth drone, says that if Iran’s claims today are true, it likely used the same electronic tactics as last time. In December 2011, Peterson described the technique, known as "spoofing":
Using knowledge gleaned from previous downed American drones and a technique proudly claimed by Iranian commanders in September, the Iranian specialists then reconfigured the drone's GPS coordinates to make it land in Iran at what the drone thought was its actual home base in Afghanistan.
"The GPS navigation is the weakest point," the Iranian engineer told the Monitor, giving the most detailed description yet published of Iran's "electronic ambush" of the highly classified US drone. "By putting noise [jamming] on the communications, you force the bird into autopilot. This is where the bird loses its brain."
The “spoofing” technique that the Iranians used – which took into account precise landing altitudes, as well as latitudinal and longitudinal data – made the drone “land on its own where we wanted it to, without having to crack the remote-control signals and communications” from the US control center, says the engineer.