Methods Of Pulse Acoustic Source Localization And Its Experimental Analysis Based On Microphone Array

Short pulse sound signal contains many types, such as gunfire, explosions, and structure fracture, etc. Since the signal is short in time domain and the intensity is always strong, pulse peak is obvious. When the pulse acoustic localization was carried out indoor, the TDE precision is very low from the same source between different receiving channels due to the effects of reverberation and noise, so that the positioning accuracy is very low and even positioning error will occur. Unlike speech signal, we cannot use moving average method to eliminate part of errors for short pulse signal because of its shorter duration. Therefore, the time delay estimation performance is a very important factor for positioning accuracy. Herein, this dissertation focuses on microphone array based indoor pulse acoustic localization methods and its experimental analysis, and the contributions are as follows:(1) Summarized cross-correlation time delay estimation(TDE) and least-mean-square time delay estimation(LMSTDE) method. To verify the effectiveness of TDE, carry out algorithm simulation work using the measured pulse acoustic signal data, and then summarize their respective advantages and disadvantages. Based on this, put forward an accurate delay extraction method based on endpoint detection, contrasted and analyzed the TDE performance before and after the extraction, validated the effectiveness of the proposed method.(2) Used the principle of the least squares method and the optimization method to solve the sound source location. Designed a mixing L-shaped microphone array composed of six microphones. Used the least square method and the optimization method respectively to simulation analysis of the factors which influence positioning accuracy such as time delay, aperture, location, and radical distance etc. and compared the advantages and disadvantages of the two methods.(3) Proposed a single pulse sound source location scheme, and then set up a demonstration system, simulated point source, carried out a large number of pulse acoustic positioning test in the indoor environment. Investigates the array aperture, the sound source location, sampling frequency which effect on the positioning accuracy and test the success rate respectively. The test results show that the scheme can overcome the effect of reverberation and synchronous non-Gaussian white noise, achieve the single pulse source of real-time accurate positioning, and has good robustness. When the distance from sound source to reference microphone is less than 4 m, level positioning accuracy can reach cm; Distance in 4 m to 6 m, the position error is not more than 0.2 m. Finally, recommendations of how to improve the positioning accuracy were put forward.