The public more and more embraces the possibilities that result from the use of drones or unmanned area vehicles (UAV). However, the limit of the use of drones is clearly privacy. In today’s competitive and internationally networked world, no individual and especially no company wants their secrets to be spied out. As a consequence, with an increased use of drones also rises the need for drone defense. Since the interests of the drone pilot / owner and the defender conflict in these cases, the legality of drone defense measures is of particular importance.

The Great Variety of Drone Defense Measures

Drone defense divides into two stages. First, the invading drone is identified and localized; second, the drone can be averted. Measures to identify and localize the drone do not target the drone as such and therefore classify as non-invasive measures. Contrarily, measures undertaken to avert the drone aim to impact on the functioning or substance of the drone and thus classify as invasive measures. The following (non-exhaustive) list shall provide an overview of the available drone defense measures:

Non-invasive measures

Invasive measures

  • Visual identification aerial surveillance by video or helicopter
  • Geofencing virtual fences that hinder the drone from flying into the restricted airspace
  • Frequency sensors scanning of the for communication commonly used frequency band
  • Net guns/ drone catching drones catch the drone with a net and take it down to the ground
  • Directional microphones recording of the sound of the drone’s rotor blades
  • Hacking/ Hijacking reach full control over the drone by intruding the communication between drone and remote control via Wi-Fi frequencies
  • Jammer interfering transmitter to interrupt the communication between the drone and the GPS-system/ remote control
  • GPS-Spoofer simulation of wrong positioning data that directs the drone to another place
  • EMP and laser canons laser beam or electromagnetic impulses that cause the drone to overheat
  • Birds of prey trained birds of prey grab the drone and take it down
  • Guns shoot the drone down to the ground

Impact of Drone Defense Measures

The consequences of drone defense measures vary broadly in intensity. Non-invasive measures detect the drone. Frequency sensors can additionally differentiate between authorized and unauthorized drones for the respective airspace. The drone is not affected itself but its data and communication details are.

Invasive measures avert the drone. Besides affecting data and communication details, these measures bear even higher risks than non-invasive measures. An uncontrolled crash of the drone, for example, could injure people and damage other objects. Unfortunately, a drone crash is not uncommon for invasive measures. Overheating caused by EMP (electromagnetic pulse) and laser canons as well as gunshots cause drones to crash. When a drone loses communication to GPS-satellites or its remote control, which is the case when jamming a drone, it automatically enters the Fail-Safe-Mode. Every manufacturer programs the Fail-Safe-Mode differently. Mostly, drones are programmed to return to their starting points. Nevertheless, others are not programmed this way and crash because of an engine fail or after they run out of power. Damage is also threatened by scattered radiation of EMP and laser canons. Further, GPS-Spoofer can affect other aircrafts flying within its range.

Acceptance or prevention of possible consequences depend upon the applicable law. Which laws can be concerned by drone defense measures will be demonstrated on the example of German Law.

Legal Aspects Regarding Non-Invasive Measures

Visual surveillance by video might also record bystanders and therefore affect their right to protection of personality Art. 2 para I sentence 1 in connection with Art. 1 para I German Constitution (GG). Moreover, the recording could infringe data protection law which requires the consent of the concerned person (Sec. 6 para I lit. a) General Data Protection Regulation) or a legal permission to process personal data (Sec. 4 para I sentence 1 Federal Data Protection Act).

Frequency sensors and directional microphones could potentially violate provisions of the German Telecommunications Act (Sec. 89, 90 and 148 TKG) and the German Criminal Code (Sec. 201 StGB) with regard to the confidentiality of spoken word and wiretapping of messages.

Legal Aspects Regarding Invasive Measures

By destroying or influencing the drone, the right to freedom of action (Art. 2 para I GG) of the drone pilot is in question. This does only not apply to geofencing, which is based on a regular update of the drone’s system with operation ban zones in accordance with Sec. 21b German Air Traffics Regulations. The crash of a drone could also cause personal injury or property damage (Sec. 223 para I, 303 para I StGB). The use of regular firearms obviously concerns the German Arms Law. Lastly, civil property and possession rights of the drone pilot / owner are infringed.

Jammers and GPS-Spoofers aim to emit interfering signals to interrupt the communication of another device, the drone. Therefore they cannot be assigned a frequency range as per Sec. 55 V No. 3 TKG and are inadmissible in the private sector. Moreover, the influence on radio signals raise concerns as to unlawful interference committed against air transport (Sec. 315 StGB) and unlawful alteration of data (Sec. 303a para I StGB). Consideration also has to be given to the provisions of animal welfare when using birds of prey to combat a drone.


To ensure the legality of the used defense drone measures, every named provision / law has to be assessed in detail. Close examination is especially required with regard to possible reasons of justifications. Hereto, motives and rights of the drone pilot / owner and the defender have to be contrasted and weighed accordingly.