Focusing translational-variant bistatic forward-looking synthetic aperture radar data using extended azimuth non-linear chirp scaling algorithm

Translational-variant bistatic forward-looking synthetic aperture radar (TV-BFSAR) introduces three difficulties for the imaging algorithm, namely, large range cell migration (RCM), severe range-azimuth coupling and large azimuth spatial variance. To address these problems, an extended azimuth non-linear chirp scaling (EANLCS) algorithm is proposed. The essence is to remove the linear RCM and Doppler centroid and compensate the residual RCM and range-azimuth coupling terms with secondary range compression. Thereafter, the EANLCS operation is applied to eliminate the azimuth-dependent frequency-modulation rate and cubic phase terms. Experimental results demonstrate the effectiveness and superiority of the proposed algorithm in focusing TV-BFSAR data.