Analysis of motion compensation and an implementation solution for airborne SAR system

Motion compensation of airborne synthetic aperture radar (SAR) consists of motion compensation based on inertial navigation system (INS) and autofocus algorithms. This paper deeply analyzes both the two aspects on the principle and gives the implementation solution. By the motion compensation based on INS, it gives not only the influence of the precision but also the effect of the data rate and points out that the data rate of the INS is the same important as the precision of INS for better result of motion compensation. Because of its excellent compensation ability and wide compensation scope, phase gradient autofocus (PGA) is used as an effective algorithm to do autofocus work. Based on the principle of PGA, the detail approach and simulation result is presented. Additionally, this paper also points out that the bottle-neck of the real time imaging processing of airborne SAR is not the computing capacity of the processing chip but the amount of memorize of the system. Then it gives an implementation solution for airborne SAR system by using high speed DSPs and huge amount memorize, with which the real time signal processing of the imaging algorithm combined with the motion compensation can be realized.