Processing of Range Cell Migration Correction with Numerical Optimization for Synthetic Aperture Radar

Due to the presence of atmosphere turbulences and the instability of airplane platform, deviations arise between the real track and the nominal one during SAR data collection, which are referred to as motion error (ME). To account for the precision limitation of a navigation system, although roughly compensated by the use of navigation data, the residual motion error (RME) still remains. As far as range cell migration correction (RCMC), the RME makes azimuth frequency-time mapping non-linear, which causes classic RCMC failure as well as the energy spread along range direction. In this paper, an adaptive RCMC (ARCMC) algorithm is proposed. First, the residual target-to-antenna distance caused by RME is extended by polynomials. Then, at each stage, classic RCMC is fast performed under updated coefficients of polynomials until convergence. During the iteration, the sharpness of the RCMC-finished data is chosen as the cost metric. In addition, the optimal coefficients are estimated by Broyden-Fletcher-Goldfarb-Shanno (BFGS) search with adap-tive order selection. Finally, we present the raw data experiment charactering the performance of the proposed method in detail.