The Research On High Resolution SAR Target Simulation

Radar technology has been greatly developed since World War II. To obtain more information of the target, it is very important to improve the range resolution and azimuth resolution of the radar. Synthetic aperture radar has been developed to meet these requirements. Many new uses of SAR, both military and civilian, have been found in the last decade and it is almost certain that more applications of SAR imaging will increase demands on performance in terms of range, resolution and image quality. In the research of SAR, the test of sub-system is needed for system optimization. The method to validate the imaging arithmetic is also needed. So some kind of test and simulation system must been established to ensure the success of SAR development.Generally, the simulation of SAR target could be divided into three steps. The first step is generating SAR target echo data which is digital according to the target module. This step is normally processed using computer. The second step is to convert the digital data into analog signal which is video or RF signal. The final step is transmitting the analog signal to the receive unit or data process unit of SAR.The SAR target echo signal is wide band chirp signal, so the method of generating wide band chirp signal is the most important part of SAR target echo simulation. There are two methods for wide band chirp signal generation. One is analog method. The other is digital method. With the development of high speed digital circus, the digital method is easier to implement. In this paper, characterizes of the SAR target echo are analyzed. Some SAR target echo simulation systems are also introduced. A simulation system based on DDR SDRAM is described in detail. DDR SDRAM can meet the requirement of high speed data access in SAR target echo signal simulation system. The theory of the system and key techniques are also been discussed.