High-Squinted Spaceborne SAR Data Focusing in the Sliding-Spotlight Mode

Inhalt:
In this letter, a novel imaging algorithm is proposed for focusing high-squinted spaceborne Synthetic aperture radar (SAR) data in the sliding-spotlight mode. First, the linear range walk correction (LRWC) and range frequency-dependent derotation are adopted to solve the azimuth spectrum aliasing. Then, a modified range migration algorithm (RMA) is derived for precise focusing considering the nonuniformity of azimuth sampling intervals. Finally, the deramp operation combined with the improved nonlinear chirp scaling (INCS) is employed for solving the aliasing problem of azimuth time and extending the depth-of azimuth-focus (DOAF). Simulated data are processed to validate the effectiveness of the proposed method.