Study on Airship Imaging Radar Based on Aperture Synthesis Antenna

Abstract:
Based on the concept of aperture synthesis antenna array, the important problem about imaging radar system on the airship for the earth observation is investigated. The multiple phase center aperture synthesis method in time division mode is proposed which makes the synthesized phase center of thinned array identical with that of a full array; therefore it avoids the high side lobes of thinned array. Using simulated annealing algorithm to optimize the location of subarrary antennas, so as to minimize the number of the used antennas. To guarantee enough transmitting power and enhance range resolution, the multiple frequency orthogonal signals are used. As the length of array is far less than the scene width, the sub-aperture imaging method is adopted. The curve fitting and PGA (Phase Gradient Autofocus) algorithm are combined to compensate array position error to obtain precise image. The simulation results show the validity of the proposed method in the paper.