Theoretical And Experimental Research On Scattering Of Chaff Cloud And Its Coupling With Sea Surface Based On Vector Radiative Transfer Theory

Chaff cloud is one of the common interferences in the field of passive electromagnetic countermeasures.In order to improve the survival rate of the ship,the ship throws chaff cloud to interfere with the interception of the seeker.Generally,the chaff cloud in naval battle scene contains a large number of randomly distributed small wires,which makes the electromagnetic scattering calculation of chaff cloud face great challenges.The electromagnetic coupling between chaff cannot be considered in analytical algorithm,but the numerical algorithm is faced with huge computational pressure.At the same time,there are few studies on the composite scattering of chaff cloud and sea surface.In this paper,the vector radiative transport theory is used to calculate the electromagnetic scattering of the chaff cloud and its composite with the sea surface,and the composite scattering characteristics of the half space on the sea surface are obtained,which provides a reliable demonstration method for the tactical use of the chaff cloud on the sea surface.In this paper,the complex electromagnetic scattering characteristics of chaff cloud and sea surface are measured in the field,which effectively solves the problem of indoor controlled chaff cloud and its combined scattering with background.The work of this paper mainly includes the following aspects.Firstly,on the basis of clarifying the military significance of chaff cloud,the research status of chaff cloud geometry modeling,electromagnetic scattering calculation and field test at home and abroad is investigated and pointed out that the domestic research on chaff cloud geometry modeling and fast computing technology of electromagnetic scattering characteristics under complex sea background is not complete and is still in its infancy because of.the computational pressure and cost.At the same time,for the reason of sensitivity,there are few reports about the experimental technology of composite electromagnetic scattering between chaff cloud and sea surface at home and abroad.As far as the research results are concerned,it is of great academic value and practical significance to carry out the research on chaff cloud and its composite scattering with the sea surface.Secondly,the paper studies the modeling method of chaff cloud and its composite geometry with the sea surface from two aspects of simulation model and physical model.In the aspect of simulation model building,the simulation model of chaff cloud under quasi-static condition is obtained by performing translation,rotation and replication operations on a single chaff,the sea surface geometry model under different sea conditions is established according to the P-M spectrum.On this basis,the superposition method is used to obtain the chaff cloud and its composite geometric model with the sea surface.In the aspect of making physical models,the chaff cloud simulation model is partitioned,and the "foam plug" method is used to make the corresponding physical model in each partition.After this process is completed,the physical models are glued in order to get a complete chaff cloud physical model.On the sea surface,laser metal deposition 3D printing technology is used to realize the high unification of physical model and simulation model.Further,the chaff cloud and sea surface composite physical model can be obtained by adding suitable foam scaffolds between them.Then,the vector transmission theory is used to calculate the electromagnetic scattering characteristics of the chaff cloud and its composite with the sea surface.The partition algorithm is used to partition the chaff cloud,and the method of moment is used to determine the equivalent electromagnetic transmission constant in each partition.In the aspect of coupling calculation,the four path method is used to calculate the composite electromagnetic scattering of chaff cloud and sea surface.Four typical energy transmission paths are considered,namely "transmit sea surface receive","transmit chaff cloud receive","transmit sea surface chaff cloud receive" and "transmit chaff cloud sea surface receive".On this basis,the Monte Carlo method is used to solve the radiative transfer equation of composite scattering vector,that is,the incident energy is discretized into a series of "photons",and the processes of emission,collision,consumption and reception are tracked and recorded.The statistical solution of Stokes vector in the composite upper half space of chaff cloud and sea surface is obtained,and the chaff cloud can be obtained by decomposing the Stokes vector The polarization scattering characteristics of the system are discussed.Finally,in order to verify the reliability of the algorithm and carry out the research of related experimental theory,the scattering characteristics of the chaff cloud and the sea surface are measured,and the test system of the field swept radar cross section in the dark room is built,and the scattering characteristics of the sea surface,the chaff cloud and the two are obtained by using the system.Compared with the simulation results under similar conditions,the accuracy of the proposed method is verified.