Modified ERMA With Generalized Resampling for Maneuvering Highly Squinted TOPS SAR

In terrain observation by progressive scans' synthetic aperture radar (TOPS SAR) imaging, 3-D acceleration of maneuvering platforms makes conventional unfolding methods no longer applicable. Moreover, when the burst is long enough, the approximation of frequency-domain algorithms exceeds the margin of error. To solve these problems, a modified extended range migration algorithm (ERMA) with generalized azimuth resampling is proposed in this letter. First, the regularized 2-D spectrum is reconstructed by an uniform acceleration compensation and unfolding operation. Subsequently, generalized resampling eliminates the spatially variant acceleration phase and equalizes the Doppler parameters of targets within the same range cell. Finally, the TOPS SAR data are focused in azimuth wavenumber domain. The proposed method is supported by point target simulation.