Anti-parabolic model that function as the joint layer was adopted to describe the electron density distribution between the quasi-parabolic multi-lays in ionosphere. The parameters of the anti-parabolic layer, such as critical frequency, semi thickness and the layer bottom radial distance from earth-s center, were calculated on the basis of the continuous electron density distribution and its continuous derivative. The plasma frequency calculated in the quasi-parabolic model or anti-parabolic model was substituted into Appleton-Hartree formula and Snell theorem to calculate the ray trace with the help of ray geometry in the ionosphere. The three important path parameters which are the ground range, group path and phase path were calculated on this multi-layer ionosphere model with the joint layer. The relationship between the path parameters, which is influenced by the angle of incidence and the working frequency, was analyzed. The relationship between the path parameters and the angle of incidence or the working frequency was analyzed too.
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