Citation

Serrenho FG, Apolinário JA, Ramos ALL, Fernandes RP. Sensors (Basel) 2019; 19(19): s19194271.

Affiliation

Program of Defense Engineering, Military Institute of Engineering (IME), Rio de Janeiro 22290-270, Brazil. rigelfernandes@gmail.com.

Copyright

(Copyright © 2019, MDPI: Multidisciplinary Digital Publishing Institute)

DOI

10.3390/s19194271

PMID

31581585

Abstract

Unmanned aerial vehicles (UAV) are growing in popularity, and recent technological advances are fostering the development of new applications for these devices. This paper discusses the use of aerial drones as a platform for deploying a gunshot surveillance system based on an array of microphones. Notwithstanding the difficulties associated with the inherent additive noise from the rotating propellers, this application brings an important advantage: the possibility of estimating the shooter position solely based on the muzzle blast sound, with the support of a digital map of the terrain. This work focuses on direction-of-arrival (DoA) estimation methods applied to audio signals obtained from a microphone array aboard a flying drone. We investigate preprocessing and different DoA estimation techniques in order to obtain the setup that performs better for the application at hand. We use a combination of simulated and actual gunshot signals recorded using a microphone array mounted on a UAV. One of the key insights resulting from the field recordings is the importance of drone positioning, whereby all gunshots recorded in a region outside a cone open from the gun muzzle presented a hit rate close to 96%. Based on experimental results, we claim that reliable bearing estimates can be achieved using a microphone array mounted on a drone.

Language: en

Keywords

direction of arrival (DoA) estimation; gunshot audio surveillance; microphone array; rotary wing drones; shooter localization; unmanned aerial vehicles (UAV)