The Swarm Killer

The latest threat: swarms of unmanned aerial vehicles designed to overwhelm their under-equipped target. Isis combatants abroad and hostage takers in the United States have started using squadrons of offthe-shelf drones to annoy and surveil, and even to d

ARMED FORCES and law enforcement have surprisingly few effective anti-drone tools, and none – that are declassified – to target multiple unmanned aerial vehicles ( UAVS), or swarms. Shotgun shells that fire nets to snare the propellers work only at close range. Missiles, such as the halfa-million-rand Stinger, aren’t really costefficient for taking out R12 000 drones. And high-power lasers and signal jammers are effective, but must be fixed on a target for several seconds before they disable a UAV. Earlier this year, Raytheon released details on a new type of drone defense using high- power microwaves (HPM).

The same electromagnetic energy you use to reheat pizza can knock out drones in less than a second. HPM beams work on the atomic level, passing through a drone’s exterior and distorting the fragile semiconductors that keep the drone aloft. Once the target is in sight, as little as a microsecond’s worth of silent, invisible microwaves moves at the speed of light, frying the circuits, says Don Sullivan, a director at Raytheon who worked on the HPM. And critically, the beam can be manipulated into a cone shape, creating an effective field that can quickly knock out multiple UAVS, with an energy cost of less than R14 per kill.

The system acts largely autonomously, detecting, identifying, and tracking its targets with AESA (active electronically scanned array) radar. It’s the same radar found on modern fighter jets. AESA uses an array of thousands of modules that change direction almost instantaneously, detecting targets more quickly and more accurately than an older spinning- disc system or infrared systems that may not pick up the minimal heat signature from a quadcopter. Though the HPM system requires little human input, the order to engage targets remains with its operator.