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A ground moving target usually shifts its initial azimuth location in the synthetic aperture radar (SAR) image due to the radial motion. To address this problem, a new azimuth relocation method is proposed for a multichannel SAR in this letter. Based on the signal analysis in the range-compressed domain, it is found that the zeroth-order term of the interferometric phase without coregistration is determined by the moving target’s initial azimuth location. A new azimuth relocation method utilizing the noncoregistrated interferometric phase is then proposed. First, the moving target is detected after clutter suppression in the range-compressed domain. Then, the interferometric phase along the slow time without coregistration can be extracted for parameter estimation via the least-squares method. Compared with the existing radial velocity-based relocation methods, the proposed method has higher accuracy, and there is no azimuth location ambiguity problem even when the target has a large radial velocity. Finally, both the simulated and real data are provided to demonstrate the effectiveness of the proposed method.

Target detection in a synthetic aperture radar (SAR) image via constant false alarm rate (CFAR) suffers from a high computational complexity, especially for the SAR image with high resolution and wide swath. In this paper, a fast implementation of cell averaging CFAR is proposed. First, a reference image is designed based on the size of the square hollow-stencil sliding window in CA-CFAR. Second, the cross-correlation between the SAR image and the designed reference image is calculated quickly by fast Fourier transform to obtain the clutter statistics. Third, the adaptive threshold can be determined based on the clutter statistics and a given false alarm probability. Compared with the existing fast CA-CFAR method, the proposed method has a much lower computational load. Finally, both the theoretical analysis and numerical experiments are provided to demonstrate the effectiveness of the proposed method.