基于反向射线追踪的多径预测方法研究

多径效应是影响通信、导航系统性能的关键因素，不仅影响信号传播的功率衰落，还会引起信号时延、频移、极化等参数的变化，导致通信、导航系统性能下降。针对多径效应，本文提出基于虚拟源树、环境分区处理、背向检测等加速技术的反向射线追踪算法进行快速三维路径追踪，准确预测多径信号的损耗、时延分布。在此基础上，以城市场景为例进行算法仿真，并对任意尖劈绕射算法进行了深入研究。最后以信号在简易街道传播为例，对比分别利用基于本文提出的算法原理的MATLAB程序和利用Wireless Insite仿真得到的反射路径与功率分布，验证了算法的有效性。

Research on the method of multipath prediction based on backward ray tracing

Multipath is the key factor which affects communication, navigation system performance. It not only affects the signal power, but also causes time delay, frequency shift and polarization parameters changing, resulting in a decrease in the communication and navigation system. To solve this problem, the fast reverse ray tracing algorithm based on virtual source tree, partition, backward detection, is proposed to predict multipath signal loss and delay distribution accurately. Besides, the urban scenes are taken as examples to show the algorithm of signal multipath transmission, and the diffraction algorithm is studied to improve the accuracy of the prediction. Finally, taking the signal propagation through simplified street models for example, the consistency of reflection path and power distribution can be proved by comparing the MATLAB program based on the algorithm which is mentioned in this paper and the simulation from using Wireless Insite software, in which way, the validity of the algroithm is also verified.