Attacks can be very different – needless to say, that counter drone measures must be manifold too and there are various techniques available today. The graph shows a selection of counter drone technology manufacturers – this list is not comprehensive.
Drone detection can be done optically, acoustically or by scanning radio frequencies. This provides the information that a drone is somewhere near you – it doesn’t provide the information where it is exactly and what direction it is flying (e.g. like a fly in your living room: you can hear it but you don’t know where it is exactly).
Detection, however, is the first step to localize and identify a drone to figure out if it’s friend or enemy.
Finding the specific position, speed and heading of a drone are key to initiate protective measures. Long and short range radars are being used to do that and therewith help to increase the response time for a certain countermeasure.
As mentioned before, active measures do not necessarily mean to just shoot the drone from the sky – let’s start at the lowest end of escalation. To protect your security sensitive facility from drones spying through the window, simply closing the sun-blinds might already do it. Regular checks if a drone dropped a Wi-Fi-sniffer on your roof is one example how to protect oneself against this new sort of threads.
To make sure a drone does not enter a certain security sensitive area, jamming is one possibility of active defense. The electromagnetic ‘overpressure’ brings the incoming drone to a stop until it runs out of battery and either returns home or lands.
Directional jamming means focusing the jamming signal towards the rogue drone. This can be rifle-like beam-antennas pointed at the intruder after localization. Another possibility is to intercept a drone from the ground or from the air. Net-guns are quite popular in this segment but it requires the attacker to be already very close to the area where it doesn’t belong.
Spoofing is a very advanced solution of drone defense and done via protocol manipulation, which takes advantage of weaknesses found in all digital radio protocols. This allows to safely land or steer away the attacking drone. The attackers’ remote control then is inoperative.
Using countermeasures in your own backyard is a problem. Firing net-guns or emitting strong electromagnetic fields is illegal in most countries since the latter one i.e. might not just stop drones from operating but also pacemakers. In governmental/military operations, spectrum regulation may not apply. Shielding the G7 summit in Elmau back in 2015 i.e. was a joint effort in line with the federal network agency.
Attacks can be very different needless to say, that.