The Study Of Moving Target Detection Methods For Single Channel SAR Data

Moving Target Detection has always been a hot research topic in Synthesis Aperture Radar research area, which plays an important role in military and civil application. Lots of Airborne and Spaceborne SAR platforms use the single channel raw data to detect moving targets. And with the improved quality of SAR system, people require higher performace of the accuracy and realtime process of moving target detection. Therefore, research on moving targets detection in single channel SAR data is significant in SAR area.This thesis mainly studies the MTD technologies using single channel SAR data. After thoroughly explaining the imaging mechanism and imaging algorithm in SAR and effects of moving targets on the conventional SAR images, it brings out the scheme of a real-time Moving Target Detection system in X wave band in details. Then, at the end of this thesis, two time-frequency analysis techniques for moving targets detection in SAR images are studied. The major devotement of this thesis is as follows:1. Proposed a frequency spectrum subdivision MTD method in single-channel SAR data and designed the whole flow chart of the detection process and elaborates on every detail. It proposed the solutions for several key technologies, including revised algorithm of central frequency estimate, sub-aperture process method for all three different imaging mode, design of the azimuth match filter and realization of CFAR detection.2. Studied on two creative time-frequency analysis method, which are Discrete Chirp-Fourier Transform and Fractional Fourier Transform. Their preliminary theory and properties, the feasibility of application in SAR are discussed. The difference between DCFT model and MDCFT model and their application restriction are stated in new interpretation based on the speciality of LFM signals. The relationship between frFT and Wavelet and the relationship between frFT and Wigner-Ville Distribution are studied by using strict mathematic formulation.In sum, this thesis not only revised the convensional MTD method using the frequency spectrum for the real-time application, but also analyses the feasibility of the newly developed time-frequency analysis technologies.