基于斜向探测最高可用频率反演电离层参数

提出了一种利用斜向探测F₂层最高可用频率及其对应时延反演传播路径中点临界频率f₀F₂和3000km传输因子M（3000）F₂的新方法.该方法从工程实用角度出发，利用射线传播理论直接反演得到临界频率和3000km传输因子.通过对长春-径阳和新乡-赤峰两条斜向探测链路中点电离层参数的反演分析，验证了方法的稳定性；利用反演结果与北京垂直探测数据对比，验证了方法的准确性；通过与Smith方法的对比，验证了方法的实用性.统计分析显示，此方法具有与Smith方法可比的精度，明显优于参考电离层模型给出的结果，其均方误差为0.48MHz，相对误差为10.50%；具有较好的稳定性，对不同距离的探测链路有较好的适应性，反演精度差异为0.03MHz；具有可操作性强，易于实现的特点.本研究成果可用于短波通信频率实时预报、动态频率管理及其相关领域. 

Method for determining the critical frequency and propagation factor at the path midpoint from maximum usable frequency and its propagation delay based on oblique sounder

Accurately determining critical frequency and propagation factor of ionosphere was important to frequency forecast and management of short-wave communication. Oblique sounder provide a valid method for real-time observation of it. A new practicable method was presented for determining f₀F₂ and M(3000)F₂ at the path midpoint from the oblique sounding data, which was based on simple oblique ray theory and only rely on maximum observation frequency and its propagation delay. The inversion from oblique sounding data on the Changchun-Jingyang and Xinxiang-Chifeng path, were compared with the vertical sounding data in Beijing during October 2009. According to analysis, the stability, accuracy and practicability of the new method are validated. The results show that the root-mean-square error of the new inverse method is 0.48MHz, and the relative root-mean-square error is 10.50%. It is obvious that the new inverse method is better than Smith's method and reference ionosphere of China. Moreover, the method is simple and easy to use. It provides the basis for frequency forecast and management of short-wave communication, and help to know ionospheric variational characteristics.