Study On The Fully-polarized Electromagnetic Scattering Characteristics Of High-density Large-number Chaff Cloud

The complex optoelectronic confrontation environment is a characteristic of modern hightech war.How to extract and identify military target features from the complex photoelectric environment has become a subject of great interest to researchers engaged in target characteristics at home and abroad.In order to protect our own military strength and important strategic facilities,passive and active jamming technology interferes and decoys by simulating electromagnetic radiation from aircraft,ships,tanks and other important military targets,making detection and tracking guidance systems blind.Chaff cloud of randomly distributed complex structures is such a passive jammer.According to the theory of vector radiation transmission and Monte Carlo method,the paper studies the full-polarization electromagnetic scattering characteristics of high-density,largequantity randomly distributed dynamic chaff clouds and their application in passive electronic countermeasures.The main research work and results are as follows:Based on the antenna principle,a fully polarized scattering field model of a single chaff is established.The polarization transformation matrix of the local coordinate system and the observation coordinate system is derived,and the correctness of the phase function composed of the generalized scattering matrix is proved.The distribution characteristics of different polarization electromagnetic scattering cross sections of chaffs under different foil orientation angles are numerically analyzed.The motion diffusion model of the chaff cloud is established.The trajectory of the spherical chaff cloud in space and the variation of the radius under the action of external force and gravity are analyzed numerically.A vector transport equation method for full-polarized multiple electromagnetic scattering of spherical chaff cloud is proposed.The geometric model of random distribution of chaff in cloud cluster is established.Monte Carlo method is used to study the transport process and polarization direction transformation method of electromagnetic wave in chaff cloud.The angular distribution of the fully polarized electromagnetic scattering cross-section of electromagnetic waves incident at different frequencies with different number and different radius chaff clouds are analyzed numerically.For large number of high-density chaff clouds,the numerical results agree well with the experimental data of the US shooting range,and the ineffectiveness of the traditional low-density cloud electromagnetic scattering cross section calculation method is expounded.Combined with the motion diffusion model of chaff cloud,the variation of backscattering cross section of dynamic chaff cloud is studied.The radar cross section of a plurality of chaff clouds is calculated by the vector superposition method.The co-polarized radar cross-section components and the cross-polarized radar cross-section components of the chaff cloud clusters with different radii and quantities are analyzed numerically.And the effects of different polarized waves incidence on the scattering field characteristics are also analyzed.The distribution characteristics of the co-polarized radar cross-section component and the cross-polarized radar cross-section component are compared.The results indicate that the electromagnetic scattering of chaff clouds with large quantity and high density has obvious depolarization effect,which provides technical support for electronic countermeasures.