A Surface Grid Fast BP Method for Spaceborne SAR Imaging

In the previous spaceborne SAR imaging methods based on time domain algorithm, the imaging grids are usually arranged in a flat plane. However, for ultra-large width and ultra-high resolution imaging, the quadratic phase error caused by surface bending is large, which makes the images defocus. In this paper, the surface grid is arranged for accurate imaging, and a new two-step spectrum compression function is proposed to achieve sub-aperture images fusion.