Ground-Based SAR Wide View Angle Full-Field Imaging Algorithm Based on Keystone Formatting

The interest of applying ground-based synthetic aperture radar (GB-SAR) in terrain displacement monitoring has increased for decades. Due to the large illuminating coverage and suitable working bandwidth, GB-SAR can achieve multitemporal surface deformation maps of the entire terrain with high spatial resolution and submilimetric accuracy. Unfortunately, focusing GB-SAR data in an efficient way is accompanied with a series of complicated engineering problems and should be solved. In this paper, a novel imaging algorithm tailored for GB-SAR data is proposed. First, the main characteristics of GB-SAR data are analyzed, and a signal model is then built up. Second, corresponding to this model, an imaging algorithm is put forward, which is based on keystone formatting and range-Doppler domain blocking. This algorithm is phase-preserving and can be widely applied in near-field, far-field, and wide view angle scenarios. Moreover, its computational cost is quite low, which includes only one time of linear interpolation and several times of fast Fourier transforms and complex multiplications. Finally, the algorithm is extensively validated both with numerical simulations and real GB-SAR data.