Research On Sound Source Location Method Based On Small Digital Microphone Array

With the rapid development of voice interaction technology,the sound source location method based on array signal processing technology combined with microphone array has attracted more and more attention at home and abroad,and has developed rapidly in the military and civil fields.In the military field,this method has been applied to enemy sniper detection,low altitude armed helicopter tracking and new intelligent mines.It has broad application prospects in the fields of civil intelligent security,remote conference and industrial machinery fault detection.However,how to achieve efficient,real-time and accurate positioning in complex environment is still an urgent problem to be solved in this field.Firstly,this paper introduces three kinds of current mainstream sound source location methods in detail.Because the traditional algorithm is easy to be disturbed,which makes the results deviate greatly,this paper makes relevant improvements on the basis of the existing algorithm,takes the digital MEMS microphone as the sound sensor,builds a planar four element microphone array,and carries out experimental tests combined with the improved algorithm.The work contents are as follows:Firstly,the development status of microphone array positioning technology is investigated.Considering the practicability,algorithm complexity and positioning accuracy of the system,the method based on time difference of arrival（TDOA）is adopted as the positioning algorithm of the system;Secondly,due to the existence of noise and reverberation,the estimation error of the traditional TDOA algorithm will be too large.This paper improves the existing algorithm by inserting a weighting factor into the Phat function and combined with the quadratic correlation function.Compared with the estimation results of other algorithms,it has less error and better performance under the condition of noise and reverberation.Subsequently,the planar four element microphone array model is designed,and its geometric positioning method is theoretically deduced and error analysis.Combined with the improved time delay estimation method proposed in this paper,the sound source location is effectively realized;Finally,the hardware design of microphone array and the software development method of multi-channel data synchronous acquisition system based on FPGA are proposed.The simulation test results show that it is consistent with the expected design and can stably and reliably complete the tasks of data acquisition and processing.The sound source positioning system is built and tested.For the collected pulse density modulation signal（PDM）,CIC filter is used to decode PDM signal.The final test results show that the sound source positioning system designed in this paper can effectively realize the sound source target positioning in the indoor environment.