Research On Electromagnetic Scattering Properties Of Moving Targets With High Speed In Three-dimensional Space

When a target moves at high speed in space,its electromagnetic scattering characteristics will be affected by the velocity or the micro motion of itself,which is different from the electromagnetic scattering characteristics of the target under static.With the increasing of speed for aircraft currently,the research on electromagnetic scattering characteristics of moving targets at high speed,and the electromagnetic scattering characteristics of moving targets at high speed with micro-motion,has attracted more and more attention from researchers at home and abroad.In order to solve the electromagnetic scattering characteristics of moving targets at high speed in three-dimensional space,the Lorentz-FDTD method is extended to three-dimensional space.A three-dimensional Lorentz-FDTD method which is suitable for solving the electromagnetic scattering problem of moving targets at high speed and moving targets at high speed with micro-motion characteristics is proposed.The electromagnetic scattering results of a moving target are obtained by this method,including the electromagnetic scattering results in the near and far fields of translational target at high speed,and the electromagnetic scattering results of a moving target at high speed with the micro-motion characteristics.Based on the finite difference time domain method,the Lorentz transformation is used to give the variable transformation relationship between different coordinate systems,including transformation of time interval,transformation of spatial interval,transformation of incident wave and transformation of electromagnetic field values.By combining with three-dimensional interpolation technology,electromagnetic scattering results of complex targets in various motion states at high speed are obtained.For electromagnetic scattering problem of translational target at high speed and micro-motion target,the derivation process of the detailed iterative formula of Lorentz-FDTD method in three dimensional is given.For a translational target at high speed,the radiation fields of a moving dipole source and the radar cross section(RCS)of a moving metallic spherical target are given.The validity and accuracy of the proposed method are verified by comparing with the corresponding analytical solutions.The electromagnetic scattering characteristics of complex moving targets,such as the electromagnetic scattering results of metallic ellipsoidal moving targets and metallic pyramidal moving targets,are analyzed by this method.The RCS of a metallic ellipsoidal moving target can be modulated with velocity.The distribution of electromagnetic fields around the metallic pyramid-shaped moving target at high speed and the waveforms in time domain of the observed points in scattering field are obtained.For a moving target at high speed with micro motion,the results of a moving cone target in the state of nutation and coning are given.Compared with the results of the existing literature,the validity and accuracy of the proposed method are verified.The electromagnetic scattering results of a moving cylindrical target with micro motion are given by this method.The state of micro motion combines coning with nutation.By calculating the energy of scattered waves in simulation results,the spectrum of the energy for a moving target is given.By analyzing the distribution of frequency at peak in the spectrum,the characteristics of micro motion for a moving target can be obtained,and the state of micro motion for the moving target is obtained.This provides a theoretical basis for different moving targets in detecting and identifying.