A sub-aperture imaging algorithm for highly squinted SAR based on frequency phase correction

A new approach of highly squinted SAR sub-aperture data processing is proposed in this paper. Under the condition of the sub-aperture characteristics, this paper presents a frequency phase correction algorithm (FPCA) for focusing SAR sub-aperture data acquired at a high squint angle and wide azimuth swath width. By introducing a disturbing phase in the azimuth frequency domain, the FPCA eliminates the azimuth-dependent frequency modulation (FM) rate and improves the final image quality effectively. The whole procedure only involves fast Fourier transforms (FFTs) and complex multiplications, with interpolation free, simulated results and raw data processing validate the effectiveness of the proposed algorithm.