Study Of The Light Scattering Characteristics From The Spatial Target Based On Ray Tracing

The Laser Scattering Characteristic of space object are calculated and studied through the monte carlo ray tracing algorithm and the bidirectional reflectance distribution function(BRDF)of different materials.In this paper,the research is based on the basic theory of radiometry.Irradiance,radiance,bidirectional reflectance distribution function and the relationship between these physical quantities are important theoretical basis of this paper.The basic principle of ray tracing algorithm is introduced,how the ray tracing algorithm is applied to calculation of light scattering characteristic has been discussed,and problems such as the calculation of the target's projected area,incidence and scattering angle,and judgment of occlusion have been solved.The ray tracker used in this paper is designed and developed,design thought and operating principle of which is introduced in detail.The accuracy of the algorithm is verified by calculating the LRCS of Lambert ball and comparing with the theoretical value.The effect of different amount of light and surface elements on the accuracy of the calculation results of different targets,such as plane and arc,is calculated and analyzed.Radiosity method and monte carlo ray tracing method are introduced to solve the rendering equation.We choose monte carlo ray tracing method to solve multiple scattering problem.The algorithm is optimized,different materials are classified,the efficiency and precision of the multiple scattering calculation are improved by determining the scope of the multiple scattering according to the BRDF of different materials.The scope of the multiple scattering of some materials which are commonly used in space objects are computed.LRCS of dihedral angle covered with lambert surface is calculated,the result is compared with the calculated result of Radiosity method,the two results are basically identical.LRCS of some simple combination is calculated,the result shows that the multiple scattering between two flats is more apparent,and materials with higher roughness produce multiple scattering in wider angles.LRCS of a scaled satellite was calculated,the results are compared with the experimental results and the multiple scattering of the satellite was analyzed.Multiple components were added to simple satellite model,expand the model to multiple material actual satellite model with complex structure.LRCS of the actual satellite model was calculated and analyzed comparing with LRCS of simple satellite model.