Acoustic Characterisation of Multi-Rotor Noise for Quiet Drone Design

Noisy drones could be a big problem for the community.
The drone acoustics problem: 1. Sound Source 2. Flight path 3. Sound receiver (person) 4. Propagation medium

The increasing use of Unmanned Aircraft Systems (UAS), commonly known as drones, both for commercial and military applications has led to concerns surrounding their safety, privacy, security, and operations. Each of these points has already been the topic of discussion, however little attention has so far been paid to the noise generated by such vehicles. This is of particular interest when considering commercial operations such as urban package-delivery, where drones will frequently be coming in close proximity to people in densely-populated areas.

This research is focused on the sound -source/-receiver relationship. The overall acoustic impact can be evaluated subjectively, indicating the human perception of multi-rotor noise. By characterising the noise generated by a typical quadcopter, and determining the geometric characteristics responsible for the largest acoustic impact, it will be possible to use this information to reduce the overall sound profile.

Identifying sound major sound source contributions using an acoustic array.

Spectrogram of a quadcopter flying overhead. Horizontal axis shows time in seconds, vertical axis shows frequency, and colour intensity indicates decibel level (loudest in centre, when multi-rotor is directly over microphone).

Nicola Kloet – PhD Candidate