Land, Sea Clutter Characteristics Modeling And Parameter Estimation

The statistical characteristic of radar clutter and the chaotic characteristic of sea clutter become the focus of current research in the Radar field, as for the wide band Radar's valuable application both in the military and civilian. Recently, the researchers home and abroad achieve some results by abundance analytical work on observed Radar clutters. In this dissertation, the observed X-band sea clutter, which obtained form the west coast of Canada by McMaster IPIX Radar, and the X/Ku_band grand clutter are discussed by modeling and simulation. The main contributions of the dissertation are as follows:Firstly, modeling of radar clutter home and abroad combined with radar clutter statistical analysis theory is introduced, including several experiential models, and methods of parameter estimation and goodness of fit. Then modeling and simulation the typical observed grand clutter (building clutter, grass clutter, forest clutter, lake clutter, agriculture clutter) and get the best parameter estimation methods for each experiential model. Last compare the performance of experiential models and obtained the best amplitude model for each kind of grand clutter. The research indicates that these experiential models just adapt some especial SAR clutter, besides for each kind of grand clutter the best amplitude statistical model is found, which is the fundament of Radar clutter target detecting.Secondly the chaos basic theory is introduced and nonlinear time series analyses based on chaos are studied involving the phase place reconstruction and the nonlinear local project noise reduction. Then the observed sea clutter is processing include three steps: step1, revised the I-Q channels data; step 2, 3-point smoothing processing; step 3, local project noise reduction is applied, here 50 neighborhood points is used for the neighborhood selection which is variable and more accurate. After the data processing, the correlation dimension and largest Lyapunov exponent are both calculated to testify that sea clutter is a dynamic system of deterministic chaos. Furthermore the statistic character is analyzed for sea clutter, which involves amplitude modeling and time correlation for each polarization. Based on a full analysis of the statistical and chaotic properties of sea clutter, the experiment results show that:MGS distribution is the best model for sea clutter, and the space correlation of hv, vh polarization is stronger than that of hh, vv.90% of the largest Lyapunov exponent is positive and the correlation dimension calculated by GPA is convergent as the embedding dimension large enough, which indicate that the sea clutter is indeed chaotic, and the correlation dimension is different for two calculational methods.Thirdly compare amplitude statistic and chaotic character performance of the sea clutter before and after noise reduction. The simulation result shows different both in statistical characteristic and chaotic characteristic, which is supposed to distinguish chaotic sea clutter form noise.Finally it is the summary of the paper and points out the problems which need further research.