Variable Scale Relative Entropy Detection for Non-Cooperative Underwater Acoustic Pulse Signals

Kun Wei,Jun Tao,Shiliang Fang

doi:10.1109/access.2020.2985051

Kun Wei, Jun Tao + Show 1 more

Open Access

https://doi.org/10.1109/access.2020.2985051

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Abstract

This work investigates the detection of non-cooperative underwater acoustic pulse signals at low signal-to-noise ratio (SNR). A variable scale relative entropy (VSRE) pulse signal detection scheme is proposed. Different from conventional relative entropy (RE) method where an observation sequence is processed at a given scale for detection, the proposed scheme performs the processing at multiple different scales. As a result, the original RE difference vector becomes a RE difference matrix, each column corresponding to a particular scale. Before a decision is made, the VSRE difference matrix is post-processed for improved fidelity. The non-zero elements of the resulting VSRE difference matrix are divided into groups, each corresponding to a pulse signal, based on their occurrence times within the observation sequence. Within each group, the one with the maximum RE difference is chosen to determine the exact appearance time and duration of the pulse signal. The performance gain of the VSRE detector over existing RE detector has been verified by both simulation and at-sea experimental results.

Highlights

A non-cooperative underwater acoustic pulse signal may come from a mechanical collision, an underwater explosion, an active sonar of the other side, and so on
We propose that a subsequence is declared to be a target pulse only when the following three conditions are met: basically match (BM), slightly to the left (SL), and slightly to the right (SR), as will be shown shortly
1) DETECTION RESULTS FOR PACKET 7 The postprocessed relative entropy (RE) difference matrix is plotted in Fig. 6, where the surviving points are divided into two groups

Summary

INTRODUCTION

A non-cooperative underwater acoustic pulse signal may come from a mechanical collision, an underwater explosion, an active sonar of the other side, and so on. Motivated by the success of relative entropy (RE) method in multi-input multi-output (MIMO) radar [14], [15], Mignerey studied the feasibility of an RE based distributed passive detection scheme [16] It is found the resulting RE detector is insensitive to statistical dependence among the sensors and achieves good performance despite of pulse type. The RE method is robust under non-stationary ocean environments It does not achieve satisfactory performance for combined pulses with different pulse widths and/or under low SNR conditions. This motivates the recent investigation on a variable scale relative entropy (VSRE) based detection [19]. The (·)T denotes the matrix transpose, and · is the Euclidean norm

PRELIMINARIES

SIMULATION RESULTS

EXPERIMENTAL RESULTS

CONCLUSION