Study On Target Location And Blind Navigation Techniques With Airborne SAR

Synthetic Aperture Radar (SAR) is a high resolution imaging radar, which can work day-and-night in all weather conditions. SAR is being applied in the fields of military and civilian with the development of principle and technique. Especially the function of imaging, SAR is can be used to search target and positioning. When the position information of target is unknown, we can use SAR to finish blind navigation, which firstly obtained the position information of target, then the information is fed back to the aircraft in real time, finally aircraft finish target attack and material delivery. The main contents of this paper are summarized as follows:Chapter 1 is the brief introduction. The history of home and overseas development about SAR are introduced. At the same time the practical application about SAR is also introduced, especially the application of SAR in the navigation is explored. Finally the overall program design of blind navigation system based on SAR imaging and positioning key technique is proposed.The accuracy of speed with radar platform influenced the target location effect. In chapter 2, Doppler measuring speed principle and application are introduced based on the introduction of key technology for blind navigation system, and simulation results verified the technique's validity.In chapter 3, the squint spotlight mode SAR imaging algorithm is studied. In order to meet the requirements of real-time, the linear range Doppler (LRD) algorithm is adopted, and the simulation results are given. This chapter also analyzed the mechanism of geometric distortion, the location algorithm of each pixel and the method of geometric distortion correction are studied. According to the ideal situation, the algorithm is effective and real-time through the simulation experiment.Chapter 4 analyzed the target position error, the parameters errors are defined, error sources and influence about each parameter for target position are analyzed. At the same time, the system parameters'influence for target position is studied. The analysis results verified the necessity of Doppler measuring speed system and provided the design specifications for blind tactical navigation system. Finally the results of comprehensive simulation experiment verified the accuracy of the error analysis theory.In chapter 5, according to the characteristics of circular-scanning SAR, circular-scanning SAR is used to validate the feasibility of the overall program. Imaging and target position based on circular-scanning SAR echo data is achieved through relative algorithm described earlier. The comprehensive error compensation scheme is given according to the analysis of target location error. Finally simulation results verified the effectiveness of the compensation scheme and the accuracy of error analysis.In chapter 6, the whole work is concluded and the possible problems to be further researched are also pointed out.