Detection, Enumeration and Localization of Underwater Acoustic Sources

The problem of passive detection, enumeration and localization of underwater objects is of great interest in several applications of sonar. Source localization requires prior knowledge of the number of sources. Therefore, detection is followed by estimation of the number of sources, and finally localization. Normally, each of the aforementioned objectives is treated as a different problem, and separate processing techniques are employed to solve them. In this paper, we propose two techniques, viz. the embedded subspace detector (ESD) and the Bartlett processor detector (BPD), for joint detection and enumeration of underwater acoustic sources using a vertical linear array of sensors. The BPD is also capable of simultaneously estimating the range and depth of each source. Simulation results indicate that the proposed detectors can achieve good detection and enumeration at low signal-to-noise ratio, and that their enumeration performance compares very favorably with those of established source enumeration techniques such as Akaike information criterion and minimum description length.