This paper deals with the imaging problem for one-stationary bistatic synthetic aperture radar (BiSAR) with highsquint,\nlarge-baseline configuration. In this bistatic configuration, accurate focusing of BiSAR data is a difficult issue\ndue to the relatively large range cell migration (RCM), severe range-azimuth coupling, and inherent azimuthgeometric\nvariance. To circumvent these issues, an enhanced azimuth nonlinear chirp scaling (NLCS) algorithm\nbased on an ellipse model is investigated in this paper. In the range processing, a method combining deramp\noperation and keystone transform (KT) is adopted to remove linear RCM completely and mitigate range-azimuth\ncross-coupling. In the azimuth focusing, an ellipse model is established to analyze and depict the characteristic of\nazimuth-variant Doppler phase. Based on the new model, an enhanced azimuth NLCS algorithm is derived to focus\none-stationary BiSAR data. Simulating results exhibited at the end of this paper validate the effectiveness of the\nproposed algorithm.
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