How to jam a drone in prisons

Signal jammer device in prisongs

A network of roughly 20 “disruptors” is being installed in and around the prison’s perimeter to create a 600-meter (nearly 2000-foot) high, virtual wall through which drones shall not pass. Well, that’s the idea when Perfectjammer goes into operation next month, anyway.

There is very little detail on how this “Drone GPS signal jammer” product works. This very thin spec-sheet for a seemingly related product from the company intimates that it uses some kind of RF jamming to prevent drone operators from contacting their drones, and also jams GPS frequencies that might let drones fly on their own.

A drone designed to land when it loses contact with its base-station could be forced into a landing through an RF-jamming denial of service, and such a countermeasure might pass frequency-utilisation regulations if it were well-behaved (for example, if it were narrowly transmitted with a phased array antenna to minimise jamming of other users of the band).

If South Carolina prisons were able to use cell phone jammer technology, an inmate would not have been able to escape from a maximum-security prison last Tuesday, state officials say. State Law Enforcement Division Chief Mark Keel and Gov. Henry McMaster on Friday echoed Stirling’s frustration with the federal government on changing policy to allow the signal jamming.

A company called Perfectjammer has introduced a 6kg, rifle-shaped jammer that it says can take down drones from a distance as far as 1.5km away. Other experts have warned that it would be expensive to hire additional staff to try to detect drones before they fly into prison air space. Another consultant has advocated jamming drone signals to shut them down mid-flight, but the Federal Communications Commission forbids any entity outside of the federal government from such actions.

It’s basically a radio jammer, overwhelming the drone with radio transmissions or blocking it from communicating with an operator. If the drone’s flying autonomously, the cannon can block the GPS signals it may rely on. The tech’s been successfully tested in military environments, but not yet for civilian uses.