An Improved Range-Doppler Algorithm In High Squint Spaceborne SAR Imaging

The main challenge faced by spaceborne SAR imaging in high squint case is the severe range-azimuth coupling caused by variation of azimuth frequency with slant range, which makes it difficult for original side-looking SAR imaging algorithms to be directly applied to high squint SAR imaging. To address this issue, this paper introduces a spaceborne high squint SAR imaging technique utilizing Range-Doppler algorithm. The relationship of the Doppler centroid with range is calculated accurately to effectively solve the problems of the asymmetric range compression sidelobes and poor edge target focusing in high squint SAR imaging, by improving the secondary range compression technique. Through simulation experiments, it was confirmed that the presented method can considerably enhance spaceborne high squint SAR imaging quality.