Ray Tracing Method For Calculating The Electromagnetic Scattering Of Targets Including The Cavity

With the increase in the large domestic aircraft projects,the study of aircraft scattering becomes more and more important.The scattering of the air intake(the cavity shape)is an important part of the total scattering.The traditional low-frequency method can accurately solve the target scattering,but it will take up huge computer resources and the speed of calculation is slow.And at the same time,the high-frequency algorithm can quickly solve the problem.It can save computer resources and can be quickly calculated.In this paper,the principle and calculation of the scattering of the open cavity structure are discussed.The SBR based on ray-tracing algorithm is a high-frequency method for calculating cavity's RCS.The algorithm is based on the combination of geometrical optics(GO)and the surface equivalence principle.It has a simple and clear physical concept and is easy to program and suitable for any shape of the cavity and the results is accurate.Firstly,the basic principle of ray tracing is introduced in this thesis.The launch of the ray,the calculation of the ray's path,and the reception of the ray are described in detail.The traditional ray tracing can not avoid large intersection operation,this part of the computing time consuming huge.Aiming at solving this problem,this thesis presents a new ray tracing algorithm based spatial division.Similar to the traditional acceleration algorithm,the propagation space is divided.The difference is that the new method divides the propagated space into several independent triangular elements(two-dimensional space)or tetrahedral elements(three-dimensional space),and uses the geometric position relation between the ray and the subdivision unit to quickly calculate the ray propagation path.So it completely avoids the intersecting test and is suitable for the ray propagation prediction in a complex environment.Secondly,The SBR is to calculate cavity scattering.The new ray tracing algorithm is introduced to quickly record the path and field strength of the ray.At the same time,the method of receiving the ray is improved and the radiation is received,and the field of the cavity surface is quickly calculated.And then with the equivalent principle of electromagnetic field,we can calculate scattering field easily.In addition,we deduces the scattering calculation formula in three-dimensional cases respectively.