Ground-based SAR imaging algorithm based on keystone formatting

In this paper, a novel imaging algorithm tailored for GBSAR data is proposed. The characteristics of GB-SAR data are firstly analyzed, and then a signal model (after range compression) is analytically built up. According to this model, our imaging algorithm, based on keystone formatting and range-Doppler domain subblock division, is then put forward, its azimuth focusing is essentially achieved through a space-variant dechirp operation. This algorithm can be widely applied to near-field and far-field as well as wide view angle GB-SAR data sets. Moreover, the computational cost of this algorithm is quite low. The image is formatted in a polar-like coordinate which is well fit for GB-SAR data. The algorithm is extensively validated both with numerical simulations and real GB-SAR data.