VTEC Modeling with Kriging Algorithm over China Area

For real-time regional VTEC(vertical total electron content) modeling over China, ionospheric modeling is realized based on spherical cap harmonic functions, low-degree spherical harmonic functions, polynomial models and Kriging interpolation techniques. This paper focuses on the spatial variability and relevance of VTEC and Kriging interpolation methodology to achieve real-time regional VTEC modeling using China regional GPS data. Results indicate that fitting accuracy in the high latitude areas is better than in lower latitude areas, Kriging interpolation and polynomial modeling show better performance than the spherical cap harmonic function and low-degree spherical harmonic function. But polynomial modeling has a marginal effect as fitting precision decreases rapidly while the distance to the center of the modeling region is increased. The variance of grid VTEC estimated using Kriging algorithm, in contrast conforms closely to the actual situation, with shows higher precision when the number of IPPs increases over the region.