Doppler beam sharpening imaging based on fast iterative adaptive approach

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Abstract
This paper proposes a Doppler beam sharpening (DBS) imaging method to achieve the high azimuth resolution in the forward-squint region based on fast iterative adaptive approach (F-IAA). In conventional DBS imaging, fast Fourier transform (FFT) method is adopted to obtain the estimation of Doppler center frequencies of targets, but it suffers from the low resolution and high sidelobes. Though a weighted least-squares based, nonparametric iterative adaptive approach (IAA) is proposed to instead of FFT method, it can not be applied to engineering applications because of its large computational complexity. In this paper, a F-IAA method, using the Gohberg-Semencul (GS)-type factorization of IAA covariance matrix, is introduced to reduce the computational complexity of brute force IAA method. Compared with the brute force IAA method, the F-IAA method mainly reduces the computational complexity of the operation of IAA covariance matrix and the inverse operation of covariance matrix. The effect is testified in simulation.