A Study On And The Implementation Of The Fast Calculations For Field Distributions Using The Ray-tracing Method

Ray tracing is widely used to predict the radio wave propagation characteristic in the environment of outdoor mobile communication and personal communication. It is based on the principle of geometrical optics, geometrical theory of diffraction and uniform geometrical theory of diffraction. Only direct, reflection, and diffraction ray is considered. When ray tracing is used to calculate the field intensity distribution, each ray and receiver is used for receiving the ball algorithm testing to determine whether the receiver receives the contribution of the ray. Its computation efficiency is low.In this thesis,the main contents and contributions are as follows:(1) The ray tracing method based on space division is explored. In the implementation, the three-dimensional space is divided into seamless and non-overlapping tetrahedrons for propagation of the rays by Gmsh. The vector algebra model between rays and simplex in three-dimensional environments is provided. Then the trajectory of rays can be found due to the simple determination of intersection points of the ray and tetrahedron surfaces by using the model.(2) The fast ray tracing algorithm of field intensity distribution is developed and improved based on the basis of previous studies. All the ray trajectory is traced by the tracing algorithm.Receiving part of the ray is improved, in order to quickly calculate the field distribution in a three-dimensional environment. The algorithm can make the result remain the same calculation accuracy and improve the computational efficiency.(3) The ray tracing method and image method are implemented in Fortran programming language. In the empty room, the comparison of calculation results verified the correctness of the space divide ray tracing algorithm and program. The fast ray tracing algorithm of field intensity distribution is implemented in Fortran programming language. The comparison between the space divide ray tracing algorithm and fast ray tracing algorithm of field intensity distribution proved that the fast ray tracing algorithm of field intensity can make the result remain the same calculation accuracy and improve the computational efficiency.