【摘要】 本文基于Ｓｎｅｌｌ定律和Ｆｅｒｍａｔ原理对三维场地任意界面情况下的两点间射线追踪问题进行了研究，从同一条射线满足相同的射线参数出发，推得一个适用于任意界面情况下计算反（折）射点的一阶近似公式。结合迭代技术，给出了三维场地条件下射线追踪迭代算法的计算格式，并进行了三维场地射线追踪模拟计算。计算表明：计算速度相当快，且其计算精度可以根据需要满足要求。更多还原

【Abstract】 A new kind of two-point 3 -D site ray-tracing method based on Snell’s law and Fermat’s principle is studied in this paper. First, it starts from the fact that the ray satisfies the same ray parameter in the whole ray -path, a one-order approximate formula which is fitted to calculation of reflection or refraction point in the random interface is deduced. Combining iterative technique, an iterative ray-tracing algorithm is obtained. Numerical tests based on this method show that it is efficient and the accuracy varies with user’s need.更多还原