A novel antenna phase center estimation method for synthetic aperture radar

For synthetic aperture radar (SAR), motion errors should be compensated to get well focused microwave images. The inertial measurement unit (IMU) is widely applied to compensate motion errors for back projection (BP) algorithm. However, the measurement errors degrade the performance of BP as well. Recently, an effective autofocus BP (ABP) algorithm has been proposed, but it ignores the spatial variance effect of motion errors and the residual phase errors defocus most pixels. For this problem, a novel motion compensation method for BP is presented in this paper. Unlike the ABP, in which the per-pulse phase errors are estimated, we estimate the errors of antenna phase centers (APCs) through optimization technique. In this way, the imaging quality of BP can be significantly improved. The simulation results validate the efficacy of this method.