| Since the ionosphere is an important media for the short-wave communication,its condition will have a decisive influence on the quality and stability of short-wave communication.Therefore,it is significant to select frequency of short-wave by detecting the information of various aspects of the ionosphere.The Wuhan Ionosphere Sounding System(WISS)can provide functions such as vertical sounding,oblique sounding and oblique back sounding of the ionosphere.According to the sounding function of WISS and the existing inversion algorithm of the ionosphere,this paper designs and develops an application to select working frequency for short-wave communication by real-time inversing ionograms.The main research contents are as follows:1.Based on the existing ionospheric sounding architecture,a method is proposed to carry out real-time frequency selection using ionospheric sounding.First,ionograms recorded by ionosondes will be inversed to obtain the electron density of the ionosphere.Then,2-D electron density profile can be reconstructed.Moreover,we can get the working frequencies of short-wave communication for different regions.2.Based on FTP technology and Windows/MFC program development technology,a software was developed to carry out frequency selection for short-wave communication.The softwave is able to implement many functions,including real-time frequency selection,plotting ionograms,plotting background spectrum,historical data query,single station browsing.3.For the spectral broadening caused by the ionospheric phase perturbation in the short-wave communication system and the Over The Horizon Radar,the phase gradient method is used to correct the phase perturbation.First,simulation was made to reduce the effect of the spectral broadening.Then,two phase gradient algorithms based on Minim Local Entropy Algorithm and Sliding Window Filter Algorithm was developed to improve the performance.Results show that the improved algorithms perform better than before. |
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