Research On Preprocessing Algorithm Of Underwater Acoustic Signal Based On Spatial-Wavenumber Filter

In the underwater acoustic communication system,the underwater environment is extremely complex.The interference of multipath effects and multiple underwater acoustic transducers sending signal at the same time in the transmission process lead to signal mix.So communication reliability and positioning accuracy are reduced.The methods that use of coding and channel equalization can't achieve very good results.In order to solve this problem,this project proposed a preprocessing method of underwater acoustic signal based on spatial-wavenumber filter.In this article,the feasibility of the algorithm is verified with characteristics of underwater signal by computer simulation based on the analysis of spatial-wavenumber filtering algorithm.And the actual underwater acoustic signal is filtered make both the communication reliability and the positioning accuracy are improved.On this basis,the filter characteristics,near-field and blind angle characteristics of the space-wavenumber filter are analyzed.To deal with the near-field and blind angle of the spatial-wavenumber filter underwater acoustic signal preprocessing algorithm,this article proposed a space-wavenumber filter optimized by window function method to suppressing the sidelobe of the space-wavenumber filter;In order to solve space-wavenumber filter near-field and blind angle problen,an preprocessing method based on near-field optimization and cross-shaped array implemented for omni-directional is proposed;When space-wavenumber is used,to know the wave number and angle of the underwater acoustic signal is necessary,but the underwater environment is extremely complex,that lead to it is difficult to obtain a priori knowledge,and a kind of underwater acoustic signal preprocessing method based on adaptive space-wavenumber filter combined with window function and omnidirectional is proposed.The simulation results show that the error rate and the positioning error of the actually underwater acoustic signals are reduced while the signals are preprocessed by three optimized space-wavenumber filter.In the case of unknown wavenumber and angle of the underwater acoustic signals,adaptive space-wavenumber filter can still restrain the multi-path interference of the underwater acoustic signal and realize the separation of multiple underwater acoustic signals.So the communication reliability and positioning accuracy areimprove.Therefore,the adaptive space-wavenumber filter is the optimal algorithm in this paper.