Acoustic Vector Array Target Signal Detection And Parameter Estimation

With the continuous innovation and development of noise reduction and acoustic stealth technology,the radiated noise of underwater targets is gradually reduced,making it difficult for traditional acoustic pressure hydrophone arrays to detect underwater targets.The vector hydrophone is composed of a sound pressure sensor and a particle vibration velocity sensor,which can simultaneously obtain the information of the orthogonal components of the sound pressure and the vibration velocity in the sound field.Compared with the traditional acoustic pressure hydrophone array,the array composed of acoustic vector hydrophone has higher processing gain and richer signal processing means.Therefore,at low signal-to-noise ratio,the use of acoustic vector array processing can improve the performance of target detection and parameter estimation.In this paper,passive detection and parameter estimation of vector array underwater narrowband targets under shallow sea conditions are studied.When the parameters of the target and the acoustic channel are partially known,different assumptions are made on the received signal model through the generalized likelihood ratio criterion,so as to design different detectors to detect the unknown signal source.The energy detector form can be given when the target and acoustic channel parameters are completely unknown.After analyzing the real received signal structure,the received signal model is constructed under the premise that the narrowband target frequency and channel parameters are a priori information,and the target azimuth and received signal are estimated by maximum likelihood estimation,and then a truncated subspace detector is given.form.When the parameters of the target and the acoustic channel are completely unknown,the received signal model is constructed by using the relationship between the sound pressure and vibration velocity of the vector hydrophone,and the approximate signal form detector is obtained by estimating the target azimuth and the received signal through the maximum likelihood estimation.The normalized mean square signal estimation error is introduced to measure the difference between the real received signal and the different received signals estimated by different models.The maximum likelihood estimation and the traditional azimuth estimation algorithm are used to realize the target azimuth estimation based on the vector array.The asymptotic performance and non-asymptotic performance of different detectors are analyzed,and the simulation results show that the truncated subspace detector can obtain better detection performance in the case of low signalto-noise ratio,the approximate signal form detector is the second,and the energy detector is the best.The target detection performance based on the vector array is better than that of the sound pressure array of the same size.In shallow seas,traditional azimuth estimation under far-field plane wave conditions will be biased,while maximum likelihood estimation can accurately estimate target azimuth.This paper studies the active detection and parameter estimation of underwater target signals of vector arrays.Firstly,the basic theory of matched filter is introduced,and the selection of commonly used active sonar emission signals is carried out through the ambiguity function.Taking the maximum output signal-to-noise ratio as the criterion,the deconvolution joint processing of the transmitted signal and the combined vibration velocity after beamforming at a certain angle in the preset azimuth interval,the addition of the sound pressure and the combined vibration velocity,and all The results of the angle are superimposed,and the active detection of the CW pulse is realized by the periodogram method.The vector array is beam-formed at a certain angle in the preset azimuth interval,the sound pressure and the combined vibration velocity are added and processed,and the results obtained from all angles are superimposed,and the matched filter is applied to realize the active detection of the LFM pulse signal.,realize the estimation of the signal delay and then estimate the target distance.