Passive Sonar Target Detection Using Statistical Classifier and Adaptive Threshold

Hamed Komari Alaie,Hassan Farsi

doi:10.3390/app8010061

Abstract

This paper presents the results of an experimental investigation about target detecting with passive sonar in Persian Gulf. Detecting propagated sounds in the water is one of the basic challenges of the researchers in sonar field. This challenge will be complex in shallow water (like Persian Gulf) and noise less vessels. Generally, in passive sonar, the targets are detected by sonar equation (with constant threshold) that increases the detection error in shallow water. The purpose of this study is proposed a new method for detecting targets in passive sonars using adaptive threshold. In this method, target signal (sound) is processed in time and frequency domain. For classifying, Bayesian classification is used and posterior distribution is estimated by Maximum Likelihood Estimation algorithm. Finally, target was detected by combining the detection points in both domains using Least Mean Square (LMS) adaptive filter. Results of this paper has showed that the proposed method has improved true detection rate by about 24% when compared other the best detection method.

Highlights

Due to the severe attenuation of radio frequency and optical signals under the sea, the use of audio signals is often a great way to detect under water targets
Sonar is divided into two families of active and passive that in the active type, by sending sound pulses and analyzing the echoes of them, we can identify the type, distance, and direction of the target
In the passive sonar, which is the topic of the project, underwater acoustic signals received by the hydrophone and after pre-processing, signal can be detected by analyzing the content of the target

Summary

Introduction

Due to the severe attenuation of radio frequency and optical signals under the sea, the use of audio signals is often a great way to detect under water targets. Sonar (Sound Navigation and Ranging) is a technique that uses sound propagation to navigate, communicate with or detect objects on or under the surface of the water, such as other vessels. These systems record the sound waves using hydrophone and by processing these signals, we can detect, locate, and classify different targets. In the passive sonar, which is the topic of the project, underwater acoustic signals received by the hydrophone and after pre-processing, signal can be detected by analyzing the content of the target. Sonar is divided into two families of active and passive that in the active type, by sending sound pulses (pings) and analyzing the echoes of them, we can identify the type, distance, and direction of the target.

Objectives

Methods

Results