Research On Short Range Passive Location With Small Scale Sensor In Shallow Water

The passive localization technology of underwater target has been one of the research hotspots in underwater acoustic engineering for a long time.In recent years,the small scale underwater sensor array has presented the advantages of small volume,easy laying,strong concealment,so domestic and foreign researchers pay more and more attention to the related researches.Study of passive localization technology based on small scale sensor array has a strong engineering application value.However,the performance of passive localization decreases sharply by complicated of ocean acoustic propagation channel.Aiming at this problem,the method of small scale sensor passive localization based on channel model is studied in this paper.In order to improve the ability of the passive localization technology in complex ocean environments,passive positioning technology is established on the foundation of the physical model of ocean acoustic propagation.Firstly,direction-of-arrival(DOA)estimation steering vector of single vector hydrophone based on Normal Mode theory is structured combining the array manifold of single vector hydrophone.The optimal weight vector of DOA estimation is obtained by vector optimization algorithm,then the robust and high resolution DOA estimation algorithm for a single vector hydrophone is established.The estimation accuracy,probability of success and the range estimation error of this method are discussed and compared with conventional beamforming(CBF)and Minimum Variance Distortionless signal Response beamforming(MVDR)in detail.Simulation results show that the vector optimization algorithm for single vector hydrophone based on channel model in this paper has higher spectral peaks and lower sidelobe under the conditions of different SNRs,incidence angles and marine environment parameters.The introduction of received signal model based on normal mode theory can reduce the DOA estimation bias effectively,which is brought by plane wave approximation;performance degradation problem caused by environmental parameter mismatch is also effectively overcome by vector optimization algorithm.The results of the sea trial data processing and analyze verify the accuracy and effectiveness of the algorithm.Secondly,according to the problem of target passive localization by small scale array in short-rang and shallow water,a passive localization method of phase correlation based on the phase information of single vector hydrophone received signal is proposed.The idea of matched field passive localization is referenced,the copy template is the phase of different frequency-distance vector broadband signal calculated by normal modes,the phase correlation algorithm in image processing is introduced,matching the copy template and received phase of broadband signal using phase correlation algorithm and get the range of target from the correlation peak.Simulation results show that the phase correlation passive ranging algorithm based on phase information of broadband signal has a sharp spectrum peak and low side lobe which can still estimate the correct target distance in the case of matched field processing and phase correlation based on intensity information failure.Furthermore,the robustness of this method is discussed and analyzed.The results show that using horizontal sound intensity and horizontal sound impedance can still give the correct target distance in the condition of ocean environment parameter mismatch,which is able to use for target passive ranging.Compared with the passive ranging method using the signal amplitude information,the method proposed in this paper is more effective.Simulation analysis proves the validity of the algorithm,which can provide a theoretical foundation for the actual engineering application.Finally,the existing underwater target ultra-short baseline passive localization algorithm is improved in this paper and 3-dimension passive localization of underwater target in short-range shallow water based on a 3-element horizontal array is realized.The received signal model of ultra-short baseline array is established and the influences of shallow water multipath effect on the performance of 3-dimension passive localization algorithm based on horizontal equilateral triangle 3 elements pressure hydrophone arrays is studied.Analysis shows that when the received signal of the array contains wideband noise,the cross phase spectra of each element of received signals will produce "oscillation phase",which can be explained by the effect of shallow water acoustic channel multipath interference.And this is an important reason for affecting delay measurement and target localization accuracy.The robustness and error of this method are analysis.The passive positioning of surface and underwater targets is implemented through the simulation experiment and the depth estimation error under different signal-to-noise is given.The simulation results show that this method can effectively estimate the target depth in a certain signal-to-noise ratio,so as to realize 3D positioning underwater target.The radiated noise signal of surface ship is analyzed and processed,and the depth of near water target is obtained by calculation.The trajectory of target is got by the localization formula of triangular array target and it is very close to the actual motion trajectory.Simulation calculation and experiment processing result both prove the effectiveness of this method.