Detection of envelope modulation and direction of arrival estimation of multiple noise sources with an acoustic vector sensor

The Detection of Envelope Modulation on Noise (DEMON) is an algorithm that is commonly applied to hydrophone data for the detection and classification of underwater noise produced by a ship. This algorithm utilizes modulation analysis to determine the frequencies that modulate the broadband cavitation noise produced by marine vessel propellers. In this paper, a DEMON demodulator for acoustic vector sensors (AVSs) that are directional hydrophones capable of acquiring both the acoustic pressure and the components of the particle velocity vector is defined. The proposed method is able to extract multiple modulating signals and measure their direction of arrival. The proposed receiver was validated with real data collected at sea with a moving buoyancy glider hosting an AVS.