Frequency-invariant direction-of-arrival estimation of circular acoustic vector sensor array for wideband signals on the cylindrical baffle

This passage discusses a method for estimating the DOA (direction-of-arrival) of broadband signal targets on the surface of a cylindrical baffle using a circular acoustic vector sensor array and based on the Minimum Variance Distortionless Response (MVDR) algorithm with joint processing of sound pressure and particle velocity. The approach employs a cylindrical baffle scattering sound field model and, according to the theory of frequency-invariant response, transforms signals at various frequency points within the bandwidth of the circular acoustic vector sensor array. It uses the transformed sound pressure and different velocity components to construct the sound pressure and particle velocity cross-covariance matrix. The spatial correlation between sound pressure and velocity components is utilized to suppress isotropic noise fields. Subsequently, the extended cross-covariance matrix for the summed and vertically arranged broadband signals is obtained, followed by singular value decomposition and reconstruction. Finally, the reconstructed cross-covariance matrix is employed for MVDR beamforming to achieve DOA estimation of targets under cylindrical baffle conditions with frequency-invariant response. Simulation and experimental data processing results indicate that, for broadband DOA estimation with a circular acoustic vector sensor array under cylindrical baffle, the joint processing of sound pressure and particle velocity using the MVDR method exhibits stronger noise suppression capabilities and higher DOA estimation performance compared to the Nehorai method. Additionally, for the joint processing of broadband signal sound pressure and particle velocity, vertically arranged cross-covariance matrices outperform summed cross-covariance matrices in terms of DOA estimation performance.