1·High frequency skywave over-the-horizon radar can provide a wide coverage beyond the horizon by means of refraction within the ionosphere.
高频天波超视距雷达通过电离层的折射作用，具有同时超视距监测大区域范围的能力。
2·High frequency (HF) communications play an important role in the field of their communications because of their skywave propagation characteristics.
短波通信由于其天波传播特性，在通信领域具有其它通信手段无法替代的地位。
3·Firstly, this paper presents an improved prediction method of maximum usable frequency (MUF) of skywave propagation based on the analysis of the current shortwave frequency prediction method.
在对当前短波频率预测方法进行分析的基础上，提出了一种天波传播最大可用频率预测的改进方法。