Research On Refined HF Frequency Prediction Of The Ionospheric Region Over Asia

With the wide application of high frequency communication technology in national defense,commerce,public security and other fields,high frequency prediction technology has gradually become a research highlight in recent years.Although the regional model possess higer accuracy than the global model,the current regional high frequency prediction model only uses the fewer sites,and modeling data for a shorter period.Moreover,the current regional prediction model research does not fully take into account the relevant prediction parameters,and high frequency prediction in Asia region has not been proposed.Therefore,in this dessertation,in order to further improve the accuracy of the high frequency prediction method,a refined usable frequency prediction method suitable for high frequency prediction in Asia has been proposed.The main contributions are as follows:(1)Based on the frequency prediction method recommended by International Telecommunication Union(ITU)and statistical analysis of ionospheric critical frequency of F₂ layer which was observed at twenty-four ionosode stations from 1948to 2018,the temporal characteristic model for the conversion factor of OWF-MUF and HPF-MUF for F₂ layer is reconstructed through two solar activity parameters(sunspot number and 10.7cm solar radio flux).Moreover,comparison and analysis were carried out in different latitudes,different solar activities and different time.(2)The spatial distribution over Asia was reconstructed by the improved Kriging method.Moreover,the spatial distribution and range of conversion factor of the low and high solar activity were compared and analyzed.(3)Using the systematic observation which was obtained by fifteen circuits received in Xinxiang,Qingdao during January 2008,March 2012,the prediction error of the proposed methods was compared with that of the ITU-R method.The result show that the predicting accuracy is effectively improved by using the 10.7cm solar radio flux.This study provides potential support for improving the accuracy for high frequency communication.