Research On Technique For Locating Noise Source By TRM Sound Focused Beamforming

Beamforing is one of the most important methods of noise source localization, which has become more and more profound after decades of research. Most of the beamforing noise source localization approaches are based on far-field models in the free field. But in the limited space, such as submarine, ship, cabin, car, etc, source is often within the near-field of the receiving array. The far-field may not be hold in practical application. In addition, there is multi-path effect in limited space. So it is important and meaningful to do the research of noise source localization in the limited space. In the paper, investigate the noise source localization in the limited space to provide the guidance in the practical application.At first, the theory of the sound focusing beamforing in the near-field is analyzed. Then, sound focusing localization model in free field is presented. Considering the effect of the interface around in the limited space, the model of sound field is built based on the theory of sound propagation in parallel layer. Use the acoustic channel theory to explain the multi-path interference on the sound in the limited space. After that, analysis the principle of the time reversal mirror from the normal wave theory and ray theory. With the above analysis, the model of sound focusing sound localization is built based on the theory of time reversal mirror.In this paper, each model is simulated with MATLAB software. The properties of the interface around, sound frequency, measuring distance, noise, distance between sources,different sound and type of the receiving array which will take effects on the sound focusing are calculated respectively. Analysis the various factors which may cause the localization errors and give the errors curves that will provide consultation in the practical application.Finally, the effect factors of the acoustic focusing noise source localization in the multi-path acoustic channel are analyzed by water-tank experimental researches, which also validate the technology's correctness, feasibility and practicability. With the result, a fundamental scheme of sound localization in the limited space is put forward.