Research On Target Localization Method Based On Vector Hydrophone

The location of underwater acoustic is an important issue in the field of underwater acoustic signal processing and underwater acoustic engineering.In this thesis,the target location methods based on vector hydrophone were chosen as the research object,and the azimuth estimation and distance estimation methods of motion target in the far field were discussed,which has certain theoretical and engineering significance.Firstly,the research and application of vector hydrophone were introduced.Vector hydrophone consists of sound pressure hydrophone and vibration hydrophone,which can simultaneously measure the sound pressure and velocity information of a point in the underwater sound field,and provide more abundant information for the treatment of the underwater acoustic signal than the sound pressure hydrophone.The vector hydrophone also has the directivity characteristic that the sound pressure hydrophone does not have.With appropriate algorithm,a single vector hydrophone can be used for the detection and positioning of the underwater target,so that the size of the sonar system can be reduced.Then the vector sound field signal processing theory was studied.When the sound field satisfies the far field plane wave condition,the sound pressure and the velocity are related to the phase source signal and are not related to the isotropic noise.The power spectrum of the radiated noise of the ship has the form of continuous spectrum superimposed line spectrum.The continuous spectrum reflects the characteristics of the sound field environment noise,and the line spectrum contains the information of the underwater targets,which is the important object in the underwater acoustic signal processing.Then the azimuth estimation algorithm based on the vector hydrophone is studied.Histogram and weighted histogram statistics are used to estimate azimuth based on the acoustic energy flow method.Equal-spaced horizontal sound pressure hydrophone array can use the ESPRIT method,with the phase difference of the received signal between the different elements,to estimate the azimuth of the targets.The vector hydrophone array can use the array manifold of the vector hydrophone to estimate the azimuth of the targets,without need to know the priori information the array formation.And the introduction of analytical vibration speed can further simplify the calculation.The single vector hydrophone can also construct the rotation invariant matrix by using the delayed data,and carry out the azimuth estimation.For moving targets,the use of sliding data processing,can improve the utilization of data,thereby improving the accuracy of the estimation.Finally,the distance estimation method of single target hydrophone for moving target is studied.For a uniform straightly moving target,the radial velocity of the sound source can be extracted from the interference pattern of the sound pressure field by changing the time interval at a given time,by using the normal mode,to estimate the moving speed and distance of the target.