Automatic detection of source direction and exclusion of irrelevant sounds in unattended noise monitoring systems

A device featuring 8 MEMS microphones has been designed, which allows localizing dominant sound sources in 3D space by implementing techniques based on time difference of arrival. The device, also called Noise Compass, is intended to be used together with an outdoor measurement microphone in a noise monitoring terminal. By defining regions of interest in the vertical and horizontal planes in a monitoring and analysis system, non-relevant sounds can be automatically detected and excluded from the noise measurements. This article describes the direction detection mechanisms and shows two examples of system application: aircraft noise monitoring and a construction site with a road and railway nearby. Finally, other system applications are discussed.