基于伪f_(o)F_(2)的短波频率预报方法及精度分析

A Frequency Prediction Method and Accuracy Analysis for HF Communications Based on Forged f_(o)F_(2)

为了满足基于现有短波信道探测链路为外推短波通信链路提供短波频率优选服务的需求,提出一种基于伪f_(o)F_(2)的短波通信链路MUF外推方法。根据探测链路实测F2电离层MUF值,采用ITU-R P.533推荐的长期预测模型进行拟合,反演出探测链路对应控点的伪f_(o)F_(2)。根据伪f_(o)F_(2)与长期预测模型中的f_(o)F_(2)关系预测外推短波通信链路控点的f_(o)F_(2),据此进一步计算外推链路的F2电离层MUF预测值。采用按比例线性缩放的模型实现根据单条链路进行外推预测,并用历史试验数据对预测误差进行了分析。结果表明,探测链路与外推链路控点距离不超过300 km时,F_(2)层MUF预测误差均值小于1 MHz,标准差小于1.5 MHz。该方法具有需要数据少,计算方便,适于多种探测数据处理等特点,为移动用户短波通信链路频率保障服务提供了灵活技术手段。

For optimizing the frequency assignment of extrapolated HF communication links based on available HF sounding links,a maximum usable frequency(MUF)extrapolation method is proposed for HF communications based on forged f_(o)F_(2).According to the MUF from the realistic sounding links on the F_(2)layer of the ionosphere,the long-term prediction model recommended by ITU-R P.533 is adopted for fitting and the forged f_(o)F_(2)values of the control point are inverted on the sounding links.According to the relationship between f_(o)F_(2)values in the long-term prediction model and the forged f_(o)F_(2),the f_(o)F_(2)value on the extrapolated HF communication links is predicted,and the corresponding MUF prediction is further calculated for the F_(2)layer of the ionosphere.A proportional scaling model of f_(o)F_(2)estimation is chosen to realize the prediction based on single sounding link.Historical experimental data is used to analyze the prediction error.The result shows that when the distance between the sounding link and the extrapolation link control point does not exceed 300 km,the expectation on the prediction error of the F_(2)layer MUF is less than 1 MHz and the standard deviation is less than 1.5 MHz.The method requires less data,is easy to calculate,and is suitable for a variety of sounding data processing,which provides flexible technical means to support frequency assignment service of HF communication links for mobile users.