RCB-based imaging method for 3-D target via curvilinear SAR

The curvilinear synthetic aperture radar (SAR) is considered as a more practicable three-dimensional (3-D) SAR imaging system. Its received data, however, are the sparse data in 3-D frequency space. Therefore, the core problem in image formation is removing the influence of the severe high sidelobes on azimuth-height plane. Robust Capon beamforming (RCB) is a non-parametric adaptive method, which can dramatically suppress the sidelobes. In this paper, the curvilinear SAR data with same range frequency are regarded as snapshots. To eliminate the coupling between the range parameter and azimuth/height parameters, the point of interest is shifted to the zeros in the directions of azimuth and height by phase compensation. With these preparations, the RCB can be utilized to estimate the amplitude of the corresponding point. The image of 3-D target is obtained when all point in the scene have been estimated. Simulation results show that the proposed method can dramatically suppress the influence of sidelobes in curvilinear SAR image formation, and the more better 3-D target images are obtained.