A new full-aperture algorithm for squint TOPSAR based on nonlinear range walk correction

Due to the steering of antenna beam in the azimuth direction and the special imaging geometry, there are two main challenges in the squint TOPSAR data processing: severe range-azimuth coupling and the azimuth signal aliasing problem. To overcome these problems, a new imaging algorithm is proposed in this paper. First, a nonlinear range walk correction (NLRWC) is applied to shear the data spectrum and remove the azimuth aliasing. Then, an extended nonlinear chirp scaling algorithm is adopted to compensate azimuth-dependent frequency modulation rate. Finally, the image can be achieved after the geometrical correction. Simulation of a point array verifies the effectiveness of the proposed algorithm.