Non-cooperative Satellite And The Ground Bistatic Sar Imaging Precision Analysis

Space-groundborne Bistatic Synthetic Aperture Radar (Bistatic SAR) system is a newly developed radar system. It has several peculiar advantages such as long operating distance, high security, anti-jammer capability etc. Moreover, the transmitter of the Spaceborne Bi-SAR system is the existing SAR satellite, so the cost of the system is less than other SAR system, and going with the increasable number of SAR satellite, it will be able to abtain rich information of targets at any time or anyplace in the world. Therefore, doing the basic and technic research of Space-groundborne Bi-SAR is one thing which suits for the need of modern war and the development of military technology.At the same time, in the Space-groundborne Bi-SAR system there are several technical problems, which affect the radar imaging, such as complicated geometrical and signal model, phase errors caused by motion errors and attitude errors, and difficulty of high resolving.Although there are plenty of basic researches on the technical problems for Airborne Bi-SAR system, few are dealing with practical realization and imaging basic researches for Space-groundborne Bi-SAR system. In this academic dissertation, several evaluative indexes of the quality for SAR imaging are introduced firstly to make a theoretical preparation for following chapters. Secondly, geometrical and echo signal model are studied for Space-groundborne Bi-SAR system. From a prototype designer's point of view, the resolving of Bi-SAR system is proposed through systematic analysis. Thirdly, phase errors caused by transmitter's and receiver's frequency source are studied for the effect on imaging. The threshold constraint and simulation result put forward also. Lastly, Doppler parameter errors, which are caused by motion errors and attitude errors of satellite's platform, are researched for how to improve the resolution of SAR's imaging. This dissertation only emphasizes the effect caused by attitude errors, because the motion errors can emendate through Inertial Navigation System. At the end, several emulational results are obtained.Besides, radar which is embedded on platform sidelooking, but the attitude errors will cause the satellite offtracking the actual flight direction. Thereby, the Doppler centroid is not zero, and Doppler frequency rate is modifing. So it needs to be estimated from the raw echo data in order to focus commendably in azimuth's direction.Finally, this academic dissertation is setting forth the laboratory test processes of Space-groundborne Bi-SAR system. At the base of that technical studies and laboratory test, a number of preparatory works are carried out for the imaging experiment successfully.