Detection of Underwater Sound Source Using Time Reversal Mirror

Taiwan is located in a crucial strategic area, surrounded by the quick-change ocean, and what remains elusive is the underwater acoustic environment. To discover the moving targets, the detection of underwater sound is very important as well as the location and tracking of the moving targets. Although the frequency characteristics of the specific target is certain, affected by the diffraction and reflection, the sound signals could have possible aliasing. In order to restore the signals, the sound source location is needed. It's common to place the hydrophones and wires at the bottom of the sea to detect the sound signals but the cost is enormous and the instruments are not easy to maintain. The purpose of this research is to join an underwater sound detecting system and a hydrophone array on a drifting buoy, and develop a technique of the moving sound source location in the sea. The sound source location would be conducted by the applications of time-reversal mirror to solve the issues of diffraction, reflection and interference of the signals, and attenuation of the sound passing channels in the ocean. Therefore, lead to a better accuracy of the sound source localization. Through this research, the position and frequency signature of the underwater sound noise of the target would be obtained and the efficiency of anti-submarine tactics could possibly be improved.