Study On Dynamic Scattering Model Of Chaff Cloud

Chaff is one of the most historical passive jammings, which is widely used in the fields of air-denfense, anti-ship and anti-missile. The battle performance of radar has been serously decreased by the development of chaff jamming technology and tactics. In order to adapt to complicated battle-field electromagnetic environment, radar urgently need to explore chaff jamming and radar targets' characteristics. This thesis mainly focuses on flake chaff, and discusse from the following two aspects of the chaff, the motion and diffusion characteristics and radar scattering characteristics of chaff cloud. The dynamic scattering model of chaff cloud is proposed through the study of these two aspects.On the motion and diffusion characteristics of chaff cloud, the force and motion manner of single chaff and the diffusion of the whole chaff cloud are studied for rare atmosphere based on free-molecular flow theory. Using the DSMC(direct simulation Monter-Carlo) method to simulate the moving of chaff cloud under the influence of different factors. According to a series of simulation results on the motion and diffusion characteristics of chaff cloud,this thesis discusses the motion and diffusion characteristics of chaff cloud for rare atmosphere, and lays the foundation for the study on the characteristics of radar scattering. On the radar scattering characteristics of chaff cloud, Using moment of method(MOM) analyses the change of radar cross section(RCS) of chaff cloud in different factors and discusses the cause of the change. The research points out that chaff cloud has strong interference effect on radar of arbitrary position, polarization mode, and frequency, it is the same to a millimeter wave radar. The code is parallelized by using Open MP, a parallel programming architecture on a multi-core computer, to accelerate the computing procedure and make full use of the multi-core computer. In the end,discusses several widely used statistical modes of RCS, analyses fluctuation characteristics of different statistical models on the RCS of chaff cloud model,and obtain a best fitting model.The motion and diffusion model based on free-molecular flow theory of chaff cloud accords with general law.The scattering results using MOM coincide with the simulated results very well. The method used in this thesis can be references to the research on electrically large target scatting problem.