I. Introduction
Detection, localization and tracking of 2-D (azimuth and elevation) direction of arrivals (DOA) of multiple acoustic sources in a noisy environment are important topics in signal processing and have many applications such as room speech enhancement, underwater target surveillance, sonar and acoustic radar signal processing. The tasks are traditionally performed by using an array equipped with several pressure sensors together with estimation techniques developed based on the acoustic pressure measurements [1], [2]. However, such techniques usually require either an array with large aperture or multiple hybrid arrays. In recent years, a new technology namely acoustic vector sensor (AVS) has been widely employed for acoustic source detection and localization, and different signal processing algorithms have been developed accordingly [3]–[25].