Study Of The Critical Frequency Of The Ionospheric F2Layerbased On High Frequency Radar

The ionosphere F2layer plays a main role in the reflection ofelectromagnetic waves, and the critical frequency of F2-layer is one of the mostimportant parameters. The critical frequency of F2-layer is very important forelectromagnetic wave propagation. It is always the focus of the study. This paperstudies the critical frequency of F2-layer, and this is useful for radar to chooseappropriate frequency. This paper tries to use echo of high frequency radar toobtain the critical frequency of F2-layer. The echo of high frequency radarcontains information of target and the ionosphere. Extracting the informationwhich we need from it is a new way, and this is different from the ways before.Now introduce the main contents of this paper below.1. The first two chapters introduce the basic knowledge of the ionosphere,the concept of the critical frequency of F2-layer, and the meaning of studying theionosphere F2layer. Also, they introduce the basic models of the ionosphere andmodels of obtaining the critical frequency of F2-layer. In the last of the secondchapter, the paper puts forward the model which will be used in this paper.2. This paper introduces how to obtain the energy of the ionosphere F2layerby using the measured data in detail. The ways contain threshold segmentationmethod, template convolution method, variance method and connected regionalgenerating method. And it uses the height knowledge of the ionosphere F2layer.At last, we obtain the energy of the ionosphere F2layer. We get a total of6setsof data. Then using the least square method to build a mode between the energyof the ionosphere F2layer and the transmission frequency.And we use thismodel to calculate and obtain the critical frequency of F2-layer.3. In the end, this paper uses the IRI-2012model to validation the accuracyof the critical frequency of F2-layer which we get by using the model. To obtainthe relative error and absolute error, and analyze the cause of the errors.