RF Detection

• RF detection is based on detection of RF signals emitted by the drone
• Commercial drones are usually operated via a radio control signal and often have on-board data link transmitters
• These can be detected and geolocated with a network of specially designed receivers well before the drone enters a protected area. 
• These intelligent nodes passively detect and identify the presence of RF transmissions that relate to drones, even if the signals are of low power or in RF noisy conditions. The transmissions can be geolocated in 3D to give the location of the drone, its flight height and air speed. 
• Multiple drones can be simultaneously tracked and identified. If a drone is detected, the system triggers an alert that can then be verified by the other sensors deployed.
• In addition, the system can detect the location of not only the drone itself, but also of the source of the control signal – i.e. the pilot

Typical RF Detection Systems

• Most RF detection system try to detect radio communication between a drone and its controller.
• Some systems are able to identify the more common drone makes and models, and some can even identify the MAC addresses of the drone and controller (if the drone uses Wi-Fi for communication). This is especially useful for prosecution purposes – proving that a particular drone and controller were active.
• More advanced RF detection system provide Direction finding, using triangulation process, similar to GPS systems
• Some high-end systems can also triangulate the drone and its controller when using multiple radio units spread far apart.

Advantages and Drawbacks of RF Detection

Pros

Can be low cost, detects (and sometimes identifies) multiple drones and controllers, passive so no licence required, some can triangulate drone and controller position.

Cons

Doesn’t always locate and track drones, can’t detect autonomous drones, less effective in crowded RF areas, typically short range.