An improved sub-aperture motion compensation algorithm for airborne repeat-pass InSAR

The center-beam approximation (CBA) in conventional twostep motion compensation (MoCo) has been one of crucial factors for high-precision airborne SAR data processing, especially for repeat-pass interferometric SAR (InSAR). The paper first proposes a useful approach based on the transfer functions of processing system to evaluate the effects of CBA on InSAR quantitatively. Meanwhile, We can obtain compensate precision required at the border of the synthetic aperture in MoCo. Then, for solving the limitations of Frequency Division MoCo (FD-MoCo) approach, an improved sub-aperture MoCo algorithm is presented where the sub-aperture is divided dynamically. Finally, images of Pband airborne InSAR with motion errors are simulated to validate the new algorithm. Compared with FD-MoCo approach, the proposed algorithm has better performance.