Modeling of ionospheric TEC around Wuhan based on GNSS

In order to study the methods and estimation strategies applicable to the regional ionospheric total electron content (TEC) modeling, this paper compares and analyzes several modeling methods and estimation strategies under the traditional single-layer hypothesis. Based on the data of 17 continuously operating reference stations in the middle latitudes of my country, the TEC modeling is carried out. The modeling methods used 4×3 polynomial model, 2nd order polynomial model, 4th order spherical harmonic series model, and the estimation strategy used piece-wise constant estimation strategy and piece-wise linear estimation strategy. On the basis of the traditional single-layer assumption, this paper also proposes a three-layer ionospheric TEC model, which can respectively give the TEC of the bottom ionosphere, peak height ionosphere and top ionosphere. The research results show that, the fitting effect of the total electron content in the zenith direction of several models is in good agreement with the ionospheric grid map published by the European Orbit Determination Center. Among them, the 4th order spherical harmonic series model and the piece-wise linear estimation strategy have the best effect. Through the three-layer ionospheric model, the relationship between the TEC and the ionospheric height can be obtained. The multi-layer ionospheric model has important application value for space target monitoring and low-orbit satellite aerospace measurement and control.