Design And Research Of Low-altitude Target Passive Acoustic Localization System

Passive acoustic localization technology can effectively locate low-altitude targets,and has the advantages of high concealment and low cost,it is widely used in military and security monitoring fields.However,in the actual positioning of low-altitude targets,due to the influence of environmental noise,the positioning results of traditional passive acoustic localization algorithms still have large errors under the environment of low signal-to-noise ratio.Aiming at the above problems,a low-altitude target passive acoustic localization system is designed,and an acoustic localization algorithm based on the Time Difference of Arrival(TDOA)is used to locate the low-altitude target.Firstly,several weighting functions of Generalized Cross Correlation(GCC)delay estimation algorithm are analyzed,and in order to reduce the delay estimation error,the generalized cross correlation-phase transform weightingadjustment parameter coherence factor(GCC-Phase Transform-ργ,GCC-PHAT-ργ)algorithm was improved in combination with quadratic correlation and the improved algorithm is verified through simulation to improve anti-interference performance and the delay estimation accuracy.Focus on the research of three-dimensional seven-element acoustic sensor array,derive the sound localization algorithm based on the time difference of arrival,and simulate and analyze the factors that affect the target sound source’s distance,azimuth and elevation angle localization accuracy.Next,the overall structure of passive acoustic positioning system for low-altitude targets is introduced;The hardware part designs the acoustic sensor array,signal processing module,and multi-channel data acquisition module;The software part introduces the system’s data acquisition and transmission module in detail,and completes the functional design of modules such as time delay estimation and positioning algorithm.Finally,a test platform was set up,and the effects of the sampling frequency and the distance of the target sound source on the positioning results were analyzed through two sets of experiments.The errors of the experimentally obtained positioning were compared with the simulation estimation errors.The experimental results show that increasing the sampling frequency of the system can reduce the positioning error.The closer or farther the target sound source will bring greater errors to the distance measurement result of the target,the more accurate the distance measurement result of the target sound source distance will be.It is accurate and verifies that the improved algorithm in this paper improves the positioning accuracy of the system.