Investigation Of SBR Based Accelerating And Hybrid Method For Composite Scattering From Large Targe And Rough Sea Surface

The study of composite electromagnetic scattering from electrically large target and complex environment is a challenging research topic in both theory and engineering.Shooting and bouncing ray(SBR)method and its related accelerating method and hybrid method is used to analyse the problems such as scattering from electrically large target,radiation pattern of antenna above an electrically large platform,and composite scattering from large warship and rough sea surface.The main works are as follows:1.Open graphics library(OpenGL)is used in the SBR method to improve the efficiency of this algorithm.The procedure of OpenGL-based paths tracing is divided into two steps,which are shadow faces removal and reflected rays searching.In addition,some OpenGL speedup schemes such as double buffering,display list,vertex buffer objects have been proposed to improve the efficiency of this OpenGL-SBR method,which make SBR method can be well applied in practice.2.Method of moments(MoM)–shooting and bouncing ray(SBR)hybrid method is proposed in this paper to analyze the radiation pattern of an antenna above an electrically large,complicated platform.MoM is applied to model the antenna,while SBR is adopted to describe the contribution of electrically large platform.The iterative algorithm is used to describe the interaction between the antenna and the platform.In addition,this study takes advantage of the outstanding rendering technique of OpenGL to accelerate the tracing process of rays from antenna.3.The shooting and bouncing ray(SBR)method based on the graphics processing unit(GPU)cluster is highly effective for solving electromagnetic scattering problems.In this paper,GPU-based SBR method is proposed to fully implement the ray tracing and electromagnetic computing of SBR method.Ray tube generation,ray tracing algorithm and electromagnetic computing is discussed in detail.Monostatic and bistatic results from en electrically large ship model demonstrated that our GPU-based SBR code can get a great speedup.And using this method,scattering properties of this electrically large ship is discussed at the influence of frequencies,incident angles.4.A hybrid scheme which combines the shooting and bouncing ray(SBR)with slopedeterministic facet model(SDFM)is presented to analyze the composite scattering from the ship-ocean scene.This model can deal with the electromagnetic interaction between the ship and sea surface very well,so that scattering properties of dynamic composite ship-ocean scene with the influence of various parameters such as incident angle,frequency,wind speed could be studied and analyzed efficiently.5.Wave motion usually causes ship's yawing,rolling or pitching motions in real ship-ocean scene.And many research indicate that the motion of the ship has the significant effect on the RCS and Doppler spectrum.In this communication,based on the motion of ship in six degrees of freedom in sea surface,inverse synthetic aperture radar(ISAR)image of dynamic marine scene is simulated and discussed with the help of our proposed efficient SBR-SDFM model.