PARIS — Cheap and deadly, Iranian-designed Shahed drones have inflicted major damage in the Middle East war, and have anti-jamming and other capabilities that make them difficult to stop. Offline navigation Designed to explode on impact, Shahed drones connect to GPS to register their location shortly before or after takeoff, then typically turn off their receivers, said Thomas Withington, a researcher at Britain's Royal United Services Institute (RUSI). The drones then travel long distances towards their target using gyroscopes that measure their speed, direction and position -- known as an "inertial navigation system." "GPS is going to get jammed by whatever is protecting the target," Withington told AFP. "If you look at a map of GPS jamming at the moment in the Middle East, you see that there's a lot of jamming... By not using the GPS, you avoid that." The drones can then return to GPS just before impact for a more precise strike, or remain offline. "It's not always necessarily very accurate, but it's as accurate as it needs to be," said Withington. Anti-jamming mechanisms Russia has been