Aviation website AviationIntel.com, however, notes that Iran recently took possession of an advanced jamming system from Russia called “Avtobaza” that perhaps could have detected communication signals going to and from the drone.
"There is no reason why [that] system could not have detected the Sentinel's electronic trail and … jammed it," the site reads.
US experts are unmoved. The US used a stealth helicopter in the Osama bin Laden raid that went undetected, and US military planes have bombed all over the world undetected. So for Iran to detect a far-smaller stealth drone seems "almost like science fiction," says John Bumgarner, chief technology officer for the US Cyber Consequences Unit, a nonprofit cyber-warfare think tank.
Provided that Iran was indeed able to pinpoint the drone overhead, the next step – jamming the GPS signal – might have been comparatively easier, US experts say.
"We have known about the weakness of GPS signals since we invented the system," says retired Air Force Lt. Gen. Harry Raduege Jr., now chairman of the Deloitte Center for Cyber Innovation. "This is not like a surprise or revelation to us."
But he and others say jamming at such high altitudes is no easy feat. Iran would have to have a very sophisticated electronic-warfare group to identify and continuously jam an encrypted signal between a drone and the satellite – and it would have to have been jammed for a long time at high altitudes, they say.