山地场景下射线跟踪法的加速技术研究

Research on acceleration technique of ray tracing method in mountain scene

在用射线跟踪技术预测山地场景下无线电波传播特性的过程中,为了提高射线跟踪算法的计算效率,提出了一种改进的基于区域划分并考虑射线方向性的加速方法。该方法连接发射点与地形三角网模型的4个顶点将地形面划分为4个区域,然后求出发射点发出的各组射线与地形面4条边的交点并根据地形模型中的三角形索引求出发射点与各交点连线所经过的网格,最后根据竖直方向上的射线方向性进一步筛除掉射线不可能相交的三角网格以减少求交次数。选取同一山地地形,在发射点和接收点位置相同情况下,分别采用所提出的加速方法与传统的八叉树加速技术进行仿真并对比分析仿真结果。数值结果表明,当发射射线条数设置为120×181时,该加速方法比传统的八叉树算法计算效率可提高50.302%,误差为9.547%。因此,相比于八叉树算法,所提方法的算法实现更简单,在提高仿真速度的同时可以保持较小的误差,具有一定的参考价值。

In the process of predicting radio wave propagation characteristics in mountain scenes by ray tracing technology,in order to improve the computational efficiency of ray tracing algorithm,an improved acceleration method based on region division and considering ray directivity is proposed.This method connects the emission point with the four vertices of the terrain triangulation model,divides the terrain surface into four regions,then calculates the intersection of each group of rays emitted by the emission point and the four edges of the terrain surface,and calculates the mesh passing through the connecting line between the starting point and each intersection according to the triangle index in the terrain model.Finally,according to the ray directivity in the vertical direction,the triangular meshes where the rays cannot intersect are further screened out to reduce the number of intersection.The same mountain terrain is selected,and the acceleration method proposed in this paper and the traditional octree acceleration technology are used to simulate and compare the simulation results.The numerical results show that when the number of emitted rays is set to 120×181,compared with the traditional octree algorithm,the calculation speed of this acceleration method is improved by 50.302%,and the error is 9.547%.Therefore,compared with the octree algorithm,the algorithm implementation of the proposed method is simpler.It can improve the simulation speed and maintain small error,which has a certain reference value.