Spaceborne Sar Moving Target Detection And Fuzzy Function Research

Spaceborne SAR (Synthetic Aperture Radar) is carried by satellite. It uses themovement of satellites, and the antennas of satellites receive the echo waves indifferent times and different locations to proceed signal processing in one CPI(Coherent Pulse Interval). This is equivalent to a real and long antenna to get betterresolution. RADAS (Radar Satellite) have been important research subjects because ofthe traits of RADAS as broad scope of irradiation, no need people to control andwell-regulated. Distributed spaceborne SAR is made of some small satellites withspecific configuration according to the request of assignments and uses the baselinesbetween satellites to accomplish targets detection task and other tasks better.Distributed spaceborne SAR usually have advantages of low cost, simple launched,broad scope, quick configuration, high resolution, anti-interference, high tolerate faultcapability and so on, so distributed spaceborne SAR becomes hot subject in recentyears and have good prospect of development.Based on the background of research above-mentioned, this dissertation mainlyaims at the ambiguity function, model and clutter characteristics analysis and movingtarget detection of distributed spaceborne SAR. This will be elaborated in thefollowing chapters.Chapter one is an introduction of the distributed spaceborne SAR system and itsresearch background and this dessertation’s contribution, innovation and structureassignment.In chapter two, we introduce ambiguity function and study the ambiguity functionof spaceborne SAR. A flight model for satellite is established and ambiguity functionof spaceborne SAR is deduced and analyzed considering the rotation of the earth, theearth’s curvature and the satellite’s orbit. The new ambiguity function is accord withreality, and provides theory for design of system parameters and forecast the resolutioncharacteristic of the system.In chapter three, we investigate the trait of clutter of ground moving target underspaceborne SAR condition. First, we deduce the effect of the rotation of the earth to the Doppler of ground clutter, and then we add the range ambiguity of echo and considerits effect to clutter. The results indicate that under the effect of rotation of the earth andrange ambiguity makes the ground clutter situation more complex, bringing moreproblems to moving target detection, last, we present some probable ways to solvethese problems.In chapter four, we research the ambiguity function and moving target detectionof distributed spaceborne SAR system. One side, we analyze the resolution ofdistributed spaceborne SAR system under different configurations, on the other side,we analyze the distributed spaceborne SAR system’s effects on the performance of themoving target detection.Chapter five is a conclusion of the whole dissertation and points out the futureworks.