Research On DOA Estimation Algorithm Of Acoustic Vector Sensor Array Based On Quaternion

As an important research direction,DOA estimation technology based on acoustic vector sensor(AVS)shows its advantages in sonar detection and positioning,underwater acoustic communication and other fields.The traditional DOA estimation method of AVS ignores the orthogonality of each channel data of vector hydrophone,so it fails to take full advantage of the advantages of vector hydrophone technology.The orthogonal structure of quaternion can ensure the inherent directivity of each component of AVS,which provides a feasible solution for making full use of vector hydrophone technology.In this context,this thesis applies quaternion theory to vector array DOA estimation and studies a series of high-resolution,robust,and low complexity DOA algorithms suitable for underwater narrowband signals.The main contents of the full thesis are as follows:1.Introduce the knowledge of quaternion theory,discuss the received signal models based on acoustic pressure and vector arrays,and then focus on three classic DOA estimation algorithms: conventional beamforming,minimum variance distortion less response,and multiple signal classification.Finally,the superiority of acoustic vector sensor array for DOA estimation is demonstrated through simulation experiments,and the performance of three algorithms for DOA estimation is compared.2.Different quaternion modeling methods for array received signals are studied.Firstly,three existing quaternion models,Q-VV,Q-PVV,and Q-PV are introduced,and compare the DOA estimation performance of MUSIC algorithm under different quaternion models;Then,in order to fully utilize the inherent directivity of AVS,the MUSIC algorithm under the improved quaternion model is studied to achieve two-dimensional DOA estimation of sound source signals;Finally,the quaternion augmentation technology,which is widely used in electromagnetic vector sensors,is introduced into acoustic vector sensor array to cascade different quaternion models.Through simulation experiments,it can be seen that the reuse of existing data by augmentation technology can improve the estimation accuracy of subspaces,and the elimination of noise can improve the robustness of algorithms,thereby improving the resolution of algorithms under this type of model.3.Research on DOA estimation algorithm based on quaternion cross correlation matrix.Firstly,a quaternion cross correlation model based on augmentation technology is proposed,which successfully eliminates additive noise by constructing a pseudo covariance matrix.In order to avoid the high computational cost of eigen decomposition of augmented matrix,the subspace is solved by using the propagator method without eigen decomposition,and the signal elevation angle is obtained by combining the ESPRIT like or MUSIC like algorithm;In order to estimate the azimuth angle of the sound source,a cross correlation matrix was constructed again,and an augmented quaternion cross correlation model without eigenvalue decomposition algorithm was studied;Finally,in order to simultaneously obtain the two-dimensional DOA of the sound source,an orthogonal propagation operator algorithm based on the cross correlation quaternion model is studied.Through simulation verification,this type of cross correlation matrix quaternion algorithm is more efficient and has better estimation accuracy.The processing of Qiandao Lake data further verified the robustness of the cross correlation matrix quaternion algorithm,which is more suitable for underwater practical application scenarios.