Acoustic Drone Detection

Military acoustic detection system manufacturers and suppliers of acoustic drone detection technology for defense applications
Overview Acoustic Drone Detection
By Dr Thomas Withington Last updated: February 5th, 2024

The Acoustic Approach: Renegade Soundwaves

Some specialist types of radar can detect drones by using the aircraft’s spinning rotor blades or by specifically detecting airborne targets with a small RCS (Radar Cross Section), but filtering out erroneous targets like birds. One drone detection technique which does not depend on radar is the acoustic approach.

Anyone who has seen a drone will be aware of the characteristic high-pitched sound of the aircraft’s motors and rotor blades. An acoustic drone detection system will use several microphones positioned on a mast. These microphones will receive ambient sound which will be fed into the system’s acoustic processor. The processor will be equipped with specialist software which will filter out extraneous sounds.

This approach is not unlike that employed by the dedicated drone detection radar which filters targets not behaving like drones either by their flight characteristics or lack of spinning blades. With extraneous sound filtered out, the processing software then ascertains the distance of the drone from the microphones and the drone’s location.

Location can be determined by triangulating the source of the sounds using the microphones. Two or more microphones can be used to determine the drone’s position by determining the relative strength of the sound waves coming from the drone’s engine and spinning blades. The more microphones the acoustic drone detection uses, the more detailed the determination of the drone’s position. Moreover, the microphones can help determine the direction in which the drone is flying.

Drone Sound Detection as Part of a Larger System

Drones present challenges from a detection perspective because of their unique design and flight characteristics. In reality, no single detection technique can detect, locate, classify and track all drones. Instead, several technologies must be combined to achieve success. To this end acoustic detection, alongside specialist radar, optronics and electronic support measures when used in concert will most likely yield the best results.