Counter Drones Knowledge Centre

Technology, on both the UAS and C-UAS fronts, is evolving rapidly. With this evolution, numerous DTI and C-UAS technology for airport-like environments are still under development but solutions are becoming available. These provide a variety of options for detection, identification, and/or mitigation. Such comprehensive layered options often combine radar, RF, audio, acoustic, cameras, and artificial intelligence (AI) for detection that could be paired with different mitigation options such as electronic interference or kinetic interdictions. For detection, the technology providers have focused on the following technologies that are considered applicable around airports:

Radar

Radar technology play an important role as a primary means of detecting UAS-based threats. Radar can detect UAS vehicles of any size by its specific radar signature. Radar can search, detect, and track multiple objects simultaneously. However, it must quickly scan large areas with high sensitivity, and be able to eliminate false hits through different algorithms. Challenges to the use of radar include lack of automation, dependence on trained operators, high system costs, and varying accuracies on detection. A key part of identifying unauthorized drones is the need to find the pilot and the radar is not able to geolocate the pilot of the UAS.

Radio Frequency (RF)

A more common UAS identification tool is the use of radio frequency or RF. The use of RF scanners provides a cost-effective solution for detecting, tracking, and identifying UAS over an average detection range of 1–3  km. This detection uses algorithms to scan known frequencies to find and geolocate RF-emitting devices with an approximate location of a UAS vehicle and its operator. This is effective if the UAS is transmitting a signal. However, RF detection sensors can only detect a few airborne subjects at a time and the accuracy could be compromised with obstacles affecting line of sight. Despite that, the use of RF has a high probability of detection with a low false alarm rate. 

Optics/Infrared (IR)

A less used detection method, optical sensors can use infrared or thermal imaging as well as a standard daylight camera to detect unauthorized UAS. The electro-optical sensors use a visual signature to detect UAS, while infrared sensors use a heat signature. The optical sensors provide visuals on the UAS vehicle and its potential payload and can record images as forensic evidence. The challenge with optical systems is that by themselves, they can be  difficult for detection because it can be challenged by redirection to false targets and is limited by weather. For increased efficiencies, the use of optics/infrared could be paired with radio frequency or radar solutions for UAS detection.

Acoustics

Another tool that could be paired with other detection systems is the use of acoustics that detect sounds produced by UAS motors. These would need strong algorithms to determine the type of UAS and be able to differentiate between authorized and unauthorized UAS. With that, performance could be impacted by wind and other background noises. The cost of this technology is low to medium with a medium probability of detection with higher false alarm rates. Another concern is the lack of geolocating the operator unlike other detection methods mentioned above.

Countermeasures and response solutions are meant to interfere with or intercept drones in order to mitigate their risk to the airport environment. These solutions may not be allowed in some States so operators are encouraged to contact their regulatory authorities. Countermeasures can be grouped into two groups: electronic and kinetic. Electronic mechanisms require the use of RF communications or GPS to be effective while kinetics use physical means to mitigate unauthorized drones. 

Electronic Jamming

The most common tool being used for mitigating drones is the use of electronic jammers. This is the intentional use of blocking signals between the UAS operator and the drone. These types of jammers can disrupt both RF and GNSS links, and once those links are jammed, the UAS is forced to land immediately or return to home location. Concerns do rise in that when a signal is jammed, there is a high probability of the drone crashing, or it could unintentionally interfere with other airport systems within the vicinity of the unauthorized UAS.

Manipulation

Manipulation of a UAS refers to a third party taking over a UAS remotely by impersonating its remote control. Manipulation employs algorithms, often enhanced with artificial intelligence, to take control of the UAS with a new, “smarter” communications link that removes the UAS from the threat environment. The manipulating signal gives a third party an opportunity to neutralize the UAS by taking over the flight and downloading its data. This technology requires extensive maintenance of libraries of the communications employed by evolving products on the marketplace, which varies by manufacturer and model.

Kinetic Mitigations

Kinetic mitigations refer to intercepting unauthorized UAS by physical means. The examples that are currently used or being tested are as follows:

• Live Fire: The use of conventional weapons, typically firearms, to target and shoot down UAS.
• Nets: UAS with attack nets capture and bring back targeted UAS.
• Use of autonomous kinetic interception methods with the option of a manned launch with monitoring.
• Lasers: Directed energy to destroy the UAS, causing it to crash to the ground.
• Birds of Prey: Trained birds with protective gear used to attack and crash UAS located in a restricted area.

Geofencing

Geofencing has mitigating qualities built into the UAS itself. This technology can be updated by manufacturers to include new and temporary restricted zones, evolving with risk-based data and information. Some manufacturers have gone so far as to expand the airport area restricted zones from two-dimensional circles to an enhanced safety zone. Manufacturers are helping to restrict access to sensitive flight locations, including airports, except for those authorized for approved UAS missions. Geofencing could also act in ensuring “careless and clueless” UAS operators are not able to interfere with airport operations.