Drones in commercial, industrial, government, public, and private spaces -- everywhere -- pose various threats. And they can be just a plain nuisance as well.
One company working on this problem is Dronefence. They have a patent-pending tech that basically uses 2 cameras in stereo and a sensor, as well as some software, to identify drones in the air, check if their registration passes muster, and sound an alarm if it doesn't. The system also records video footage of the drone.
Currently, Dronefence is just working on the identification. How to deal with intruding drones is another thing. But they've now acquired seed funding for their project from VP Capital, Larnabel Ventures, Boundary Holding, and the Technology and Business Consulting Group.