The Rise Of High-Performance Multi-Rotor Unmanned Aerial Vehicles - How worried should we be?

High-performance multirotor drones optimised for speed and agility present a significant and increasing challenge to current counter-drone systems based on jamming or physical interdiction. Existing jamming technology requires sustained visual line of sight targets and is most effective in countering threats from relatively slow and RF compliant videography drones. Physical interdiction using nets is again only suitable for low-speed interception. Small vehicles based on commercially available consumer drone technology with a mass of less than 1 kg and package size of 15 cm can achieve flight speeds in excess of 70 m/s and can accelerate at up to 15g, and are sufficiently inexpensive as to be considered disposable. Custom flight control systems bypass geofence restrictions and the wide availability of high power radio links greatly exceeding OFCOM limits significantly reduces the range over which commercial jamming systems are effective. Static acceleration performance is maximised simply by decreasing the power loading and decreasing the disc loading and is approximately independent of the size (mass) of the vehicle. Maximisation of top speed is more complex, requiring identification of an optimal disc loading that balances thrust against rotor drag. Top speed is also affected by area/volume scaling meaning that larger vehicles with the same power to weight ratio and disc loading generally have less drag and hence higher top speed. Consumer technology for very high thrust to weight ratio variants of larger multirotor drones is currently not readily available. However, 10 kg drones with a top speed of 100 m/s and static acceleration of 20 g are foreseeable in the next 5 years.