Propagation Characteristics And Application Of High Frequency Radio Waves In Middle-Low Latitude Based On Ray Tracing

The ionosphere is a region produced by the ionization of the upper atmosphere under the action of solar radiation and various cosmic rays.It plays a crurial role in the propagation of radio waves.Following the development of information technology,communication with the help of ionosphere has gradually become a part of human life.For example,radar detection,satellite communication,wireless communication,positioning and navigation of global positioning system are closely related to the propagation of radio waves in the ionosphere.In recent years,with the ray tracing technology proposed to study the propagation of highfrequency radio waves(3～30MHz)in the ionosphere,the research in this field has been the attention of scholars all over the world.Based on ray tracing technology and the International Reference Ionosphere(IRI)model,this dissertation studies the propagation characteristics of high-frequency radio waves in the middle-low latitudes and the application of ray tracing.The main work can be summarized as follows:Firstly,this dissertation introduces the structural characteristics of the ionosphere,and then summarizes the current mainstream background ionosphere models.Furthermore,the basic theory of radio wave propagation is briefly expounded,and the propagation characteristics and propagation modes of radio waves in the ionosphere are also analyzed.Secondly,based on the Haselgrove equation of ray tracing and on the basis of the background ionosphere constructed by the IRI model.In this paper,the Runge-Kutta method is used to calculate the radio wave propagation trajectory,and the influence of different emission elevation angles and different operating frequencies on the radio wave propagation trajectory is analyzed.Furthermore,using ray tracing technology,combined with the three-dimensional ionospheric background model,the prediction of the launch elevation angle and operating frequency between the two places of short-wave communication is realized.Thirdly,due to the uneven distribution of electron density in the three-dimensional ionospheric background model,the wave propagation path is deflected,and the ray landing point is deviated.A radio wave orientation correction method based on ray tracing is proposed and introduced in detail.The correction method is verified by simulation experiments.The simulation results show that after the high-frequency radio waves are oriented and corrected,the coordinates of the ray landing point meet the preset error,which improves the accuracy and reliability of short-wave communication.Finally,the oblique measurement ionogram of the transmitting point and the receiving point is simulated by ray tracing technology,and the measured ionogram is compared with the synthetic image,and it is found that the two are in good agreement at the bottom of the F layer.In addition,the Maximum Useable Frequency(MUF)between the transmitting point and the receiving point is predicted through the synthesized oblique ionogram,and the synthesized oblique ionogram is inverted using the genetic algorithm.The actual vertical measurement results are compared,and it is found that the inversion results are basically consistent with the actual measurement results,which have good reliability and practical application value.