The Study Of Vegetation Clutter Modeling And Simulation Techniques

As low frequency band foliage penetration(FOPEN)radar is able to penetrate forests,it becomes an important force when developing battlefield surveillance radar(BSR).FOPEN synthetic aperture radar(SAR)and ground FOPEN radar consist of the two primary parts in the FOPEN phenomenon research.FOPEN SAR cannot implement any surveillance mission in a long time because of SAR’s working characteristics.Therefore,this dissertation studies the vegetation clutter modeling and simulation with ground FOPEN radar.Based on the above research background,the main work is arranged as follows: the theories and principles of clutter modeling for ground FOPEN radar are expatiated(chapter 2);the method of vegetation clutter modeling based on pendulums and its improved model for different wind velocities are proposed,and some clutter simulation results are shown(chapter 3);the feasibility of the pendulum vegetation clutter model and the validity of its parameter estimation methods are demonstrated,and some appropriate suggestions of this model’s application are presented(chapter 4).In the chapter 2,the linear frequency modulation continuous wave(LFMCW)signal is chosen to establish the signal and echo models of ground FOPEN radar in different radar layouts.When studying the forest clutter,the radar cross section(RCS)of trunks and branches is analyzed;at the same time,some typical models’ probability density distribution and clutter power models and their characteristics are summarized.Using pendulums to simulate the swinging vegetation is inspired by the observation of "periodic" motions of substances.In chapter 3,classical modeling methods of internal clutter motion and the vegetation model in simple harmonic motion(SHM)are analyzed,and the vegetation clutter pendulum model based on "dicotyledonous leaf" is proposed.We further improve the model for different wind velocities,and the concept "vegetation constant" related to vegetation is proposed.The clutter simulation results using the proposed models are obtained.In addition,parameter estimation methods in the time-frequency way are proposed under the model.The work in chapter 4 is based on the research in chapter 2 and 3.It analyzes the statistical characteristics of pendulum model vegetation clutter,compared with the real data’s results of fitting to amplitude probability density distribution and the power spectrum estimation;it is shown that the model’s application is feasible.On radar system design and clutter suppression,reasonable advice is given.The vegetation clutter measurements for different wind velocities are described,and also the parameter estimation methods are demonstrated.