The Analysis Of Sea Clutter Characteristics And Target Detection Method Based On Multifractal Theory

Sea clutter is the unwanted radar echoes from sea surface. The existence of sea clutter contributes a serious disturbance to the target detection performance of radar. Sea clutter suppression technology is thus the focus of current research, and involves an valuable application both in the military and civilian, especially in the military. Two main portions are contained in the sea clutter suppression technology, these are the sea clutter modeling and the target detection technology under heavy sea state, and the ultimate goal of modeling sea clutter is to enhance some performance like target detection.Based on the research of the two major fields of sea clutter, a comprehensive analysis of the sea clutter characteristic is made in this dissertation, together with a new feature extracting method for detection. The following results towards modeling and detecting within sea clutter have benn achieved:(1) Some important statistical properties are analyzed by using the real life sea clutter data, and several common sea clutter models are introduced. Much attention is given to an ad hoc model names the compound K-distribution, it is by now the most reasonable statistical model relates to some physical mechanisms and fits the amplitude of the sea clutter. ZMNL transform is utilized here modeling and simulating K- distribution vectors with varies shape parameters.(2) The chaotic characteristic of sea clutter is introduced, that the correlation dimension and Lyapunov exponent are both calculated to testify that sea clutter is a dynamic system of deterministic chaos. Same analysis is applied to K- distribution Vector, however, K- distribution vector is proved to stand out of chaos.(3) Chaotic and fractal system are closely linked, Chaos track or the strange attractor trajectory is often the fractal. This dissertation itemizes the fractal theory, fractal concept and the calculate of fractal, then next on the multifractal. (4) Based on a full analysis of the statistical and chaotic properties of sea clutter, a new multifractal method name VFDT is taken for purpose of feature extraction and target detection. The performance of VFDT is validated by simulation method, and a nice result was reached in detection. Further more, this dissertation proposes a new fuzzy detection method based on the abundant fractal information extract from the real life data and achieves some certain effect.