Research On Time Delay Estimation Method Of Target Echo Based On Geometric Acoustic Acattering Characteristics

Time delay estimation is a key aspect of underwater sound source localization.Using the echo signals received by active sonar systems for time delay estimation can easily be affected by marine environmental noise and reverberation.How to effectively suppress interference and improve the accuracy of time delay estimation is of great significance.On the basis of summarizing the development history and current status of time delay estimation in active sonar systems,this article focuses on researching high-precision time delay estimation algorithms for targets in reverberation backgrounds,and proposes an underwater target time delay estimation algorithm based on geometric acoustic scattering characteristics.Firstly,the paper introduces the target echo highlight model based on geometric acoustic scattering theory,decomposes the test target model into simple shapes,and derives the time delay expression of each acoustic scattering center of the model relative to the reference center;And analyze the differences between the geometric acoustic scattering characteristics of the target and ocean reverberation.Secondly,in order to effectively extract the geometric echo signal of the target and suppress the influence of reverberation and noise on the echo,the paper introduces frequency slicing wavelet transform for time-frequency analysis of the received signal.To address the issue of obtaining the parameters of frequency sliced wavelet transform based on empirical formulas when the transmitted signal is a broadband signal,a joint fractional order Fourier transform frequency sliced wavelet transform time-frequency analysis algorithm is proposed;The improved algorithm improves the time-frequency clustering of the signal,enhances its noise resistance,and accurately solves the frequency slice wavelet transform parameter values of broadband signals.Finally,the paper constructs a multi angle incident signal observation matrix based on the theory of highlight model and target size information,achieving effective extraction of multiple geometric echo signals.The extracted signals are calculated using waveform similarity coefficient and mean square error,achieving accurate time delay estimation of underwater targets.The simulation results show that compared with the matched filter,the proposed delay estimation algorithm reduces the relative error by 0.2under the signal-to-noise ratio of-20 d B;The relative error is reduced by 0.15 under the condition of a signal-to-noise ratio of-5d B.The experimental data processing results show that in a strong reverberation environment,the delay estimation error is only2.83%.The paper effectively utilizes the size information of known targets,and the proposed algorithm provides a new technical approach for effective estimation of target delay under strong reverberation background conditions.