Broadband passive sonar detection using rational orthogonal wavelet filter banks

A broadband passive sonar detector based on rational orthogonal wavelet filter banks (FBs) is proposed. This wavelet-based subband energy detection approach is able to detect an emission with unknown frequency content in severe multipath and noisy ocean environment. A geometrical acoustic channel model is adopted to synthesise the echo from a moving source using ray tracing. The performance of the wavelet FB detector is analysed under designated detection scenarios with a single detector and three different random emissions varying in bandwidth, source motion velocity and direction. Two different multipath scenarios, severe multipath and one-dominant-path scenario, are simulated by modifying the depth of the detector. The receiver operating characteristic (ROC) curves are generated for the wavelet FB detector and are compared with the ROC curves of a conventional energy detector (CED) under the same scenario.