Shotguns, radio beams and firmware updates are just a few of the ways being floated to stop dangerous drones in their tracks. Another appraoach that's starting to gain a bit of traction is drone-catching nets carried by drones themselves. Following the lead of Tokyo police last month, a team of mechanical engineers has devised a retrieval system that captures small drones and carries them unharmed to desired location.

Tokyo's police department made headlines last month when it demonstrated drone-hunting aircraft that tow around large nets, intended to scoop up suspicious aircraft before they can cause any harm. Flown by riot police, the department hopes to use the vehicles to capture drones that may be lurking in sensitive areas, such as the airspace around the Japanese prime minister's office where one unmanned aircraft was intercepted in April last year.

Conceived by Mo Rastgaar, an associate professor of mechanical engineering at Michigan Technological University, this latest system does appear to be a little more sophisticated. Described as "robotic falconry," Rastgaar's solution consists of a large hexacopter with a launching system fitted to its body.

When it spots an illegal aircraft, the predator drone fires a net from as far as 40 ft (12 m) in its direction. After shrouding the smaller drone, the enclosed net is then swung back beneath the larger aircraft with its catch inside and swept away from the area.

The team says that the net is designed to be large enough to trap even the fastest and most agile of smaller drones, and it can be flown autonomously, piloted by a person on the ground or a combination of both. A patent has been filed for the system with hopes that it could find a variety of uses, such as countering terrorism, spy and drug smuggling operations, and also helping enforce new drone regulations.

"The FAA (Federal Aviation Administration) has just announced that drones must be registered, and we think the catcher could help enforce the law by catching unregistered drones," says Rastgaar.

You can see the drone-catcher do its thing in the video below.

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