A Clutter Suppression Method for Dual-channel Circular SAR-GMTI

Ground moving target indication (GMTI) technology is an important development direction in the field of SAR signal processing, and the performance of GMTI is determined by clutter suppression directly. Since the trajectory of airborne platform is a circular arc and the beam directions of antennas are time-varying in the circular SAR (CSAR) mode, the classical channel registration methods for the strip-map SAR are no longer applicable. Based on the measured data of a CSAR system, channel calibration and channel equalization are investigated to eliminate the phase and amplitude differences of the clutter between the channels. Further, according to the complementary property of displaced phase center antenna (DPCA) and along-track interferometry (ATI) technologies, we propose a clutter suppression method in the complex image domain by utilizing the interference phase of ATI to weight the DPCA amplitude. The process results of measured data prove a good capability for clutter suppression both in homogeneous and inhomogeneous areas.