Study On Methods Of Passive Target Detection And Localization Based On Acoustical Signal Processing

With the applications of target localization in all aspects of people's lives,high precision target localization technology has become the research hotspot at home and abroad.Because of its good concealment,strong anti-interference ability,high real-time performance and low power consumption,Acoustic source localization(ASL)plays a crucial role in civil and military field,such as shooter localization,sonar and earthquake prevention.However,in the actual environment,the high-precision ASL has become a challenging task under the influence of various interference factors.In view of the interference of environmental noise,the non-line of sight(NLOS)propagation of signals and other factors,the location system is liable to low accuracy.The passive target localization based on acoustical signal processing is studied.The specific details of the research content are as follows.(1)The research progress of passive source localization method is summarized and its advantages and disadvantages are concluded from different angles.In this paper,the existing methods of passive target localization based on time difference of arrival are described,the factors affecting localization are analyzed,and the evaluation indexes of localization performance are given.(2)Traditional time delay estimation technology of generalized cross correlation based on direct data,without the impacts of various environment noises and fluctuation of outlier,results the greatly attenuated of its accuracy.Time delay estimation(TDE)method that does not depend on the initial value is proposed to solve the problem,namely generalized cross correlation method with Hassab-Boucher(HB)based on singular value decomposition(SVDHB-GCC).Firstly,adopting the singular value decomposition(SVD)is not only to reduce the effect of environmental noise,but improve the signal-noise ratio of received signals.Secondly,the peak of GCC function can be sharp by introducing the Hassab-Boucher weighted function into the calculation of the power spectral density.Finally,the post processing approach based on mean and median is exploited,being able to obtain the optimal estimation of TDE by revising its abnormal fluctuation with the unknown initial value of time delay.Simulation results show that the proposed method can accurately estimate the number of delay points and highlight the strong anti-noise performance compared with other methods in an environment with high noise interference intensity.(3)In view of the interference of environmental noise,the non-line of sight propagation of signals and other factors,the location system is liable to low accuracy.A hybrid location algorithm of acoustic source based on error correction(ECHL)and time difference of arrival(TDOA)is proposed.This algorithm through correcting the weighted matrix of weighted least square(WLS)dynamically to obtain the initial value of Taylor series iteration,so as to avoid long iteration time and even divergence by random initial value.The additional delay caused by non-line-of-sight transmission will cause large positioning error.To solve this problem,a latter selection strategy of time delay is designed.The influence of the time delay with larger errors on the positioning accuracy is eliminated by combining latter selection algorithm of time delay with standardized residual function.Then the optical positioning solution of TDOA integration is chose.Finally,the target position is determined by the standardized residual weighting.Simulation results show that the proposed method can considerably outperform the single method and effectively restrain NLOS error to improve the positioning accuracy compared with reference methods.