Doppler Beam Sharpening Imaging Based on Beam-Recursion FIAA

Brute force iterative adaptive approach (IAA), utilizing weighted least squares estimation (WLSE) criterion, is a nonparametric super-resolution spectrum estimation method to effectively improve the resolution of Doppler beam sharpening (DBS) imaging. Regretfully vast calculation complexity causes a huge burden in each iteration. Though fast iterative adaptive approach (FIAA) is proposed according to the fast calculation of covariance matrix and its fast inversion by Levinson-Durbin and Toeplitz-vector operation, the fixed but unnecessary iterations of FIAA causes a new burden. This paper proposes a DBS imaging method based on beam-recursion fast iterative adaptive approach (BR-FIAA) to improve computational efficiency by promoting convergence speed. The proposed method utilizes the spatial correlation of adjacent beams. Taking the advantage of echo splitting process of DBS in cross-range, the iterative initial value of covariance matrix is updated by the former echo beam. In this way, the iteration convergence speed is improved according to the proposed BR-FIAA method, and the imaging performance is kept. Simulations are given to verify the effectiveness of proposed BR-FIAA method.