Watch this DroneHunter stop trespassing drones with radar and a net

Watch this drone attack and capture rogue drones
Watch this drone attack and capture rogue drones

A start-up called Fortem Tech has developed a drone-hunting drone to pull trespassers out of the sky with a net, while keeping onlookers safe below.

According to FAA forecasts, nearly 7 million drones will be sold in the U.S. by 2020.

Most people want to use unmanned aerial vehicles for good reasons, like gathering data or delivering life-saving medical supplies to people in need. But drones are also misused and abused.

For example, last month a civilian drone crashed into an Army helicopter above Staten Island. Drones have also crashed onto the White House lawn, into power lines (causing a major blackout), and through apartment windows and storefronts. FBI Director Christopher Wray recently predicted in congressional testimony that terrorists will try to use drones to attack people in the U.S.

Fortem's DroneHunter is adapted from a DJI octocopter, the kind typically used to hoist heavy cameras into the sky, and equipped with Fortem's lightweight radar units and net-shooting cannons. The radars are about the size of a paperback book and require only as much power as it takes to run a single LED lightbulb.

When the DroneHunter detects unauthorized drones or a possible crash, it flies after them and captures them in a net.

Bean confirmed that the DroneHunter is now used exclusively by the U.S. military and its partners to "protect fighters and bases at a safe stand-off distance with little collateral damage."

The company also sells its radar platform to other drone and security companies to enable autonomous flight and high-velocity object tracking, he said.

Investor Matt Ocko, a managing partner with Data Collective, told CNBC that his firm invested in Fortem because its tech has the potential to enable all the positive uses of drones while preventing the downsides, especially terrorist attacks. The start-up has raised $5.5 million in seed funding to date.