Analysis of the ionospheric time-varying effects on the radar echoes based on ionogram inversion

Ionogram is one of the most important sources to analyze the ionospheric real-time state. For doing this, the ionograms must be inverted into several parameters firstly. The algorithm of partial derivative iteration is often used to finish this work. But the accuracy of this inversion results are dependent on the selection of initial values. A criterion for the selection of the initial values is proposed to solve this problem. After inversion, a polynomial fitting method is used to establish the dynamic ionospheric model. Then, based on the model and the path-distance transformation, the radar echoes can be obtained. At last, changing the working bandwidth and the ionospheric parameters, we can find which parameters are the key factors to affect the radar spectrum.