Research On Kriging Interpolation Method And Ionospheric Delay Correction Models

As ionosphere is an important of sun-earth space environment has always been studying by scholars. Firstly, the ionosphere delay error has an important influence for Global Navigation Satellite System at navigation and positioning. Secondly, using GNSS monitor the variation of the ionosphere is by far the most accurate monitoring method.Finally, the studies of the ionosphere have extraordinary significancefor human life on earth. This paper focuses on the research of principles and methods of calculating the vertical electron content of the ionospheric pierce point by using GPS dual frequency observations, then selected several GPS stations within a particular region and 169 GPS stations all over the world to calculate the VTEC of the IPPs. Using the Kriging algorithm estimated the vertical electron content of the grid, and on the basis of these, comparing the results of the inverse distance weighted interpolation and Kriging to the reference IGS maps, through the experiments proved that the Kriging interpolation algorithm is better than the algorithm of inverse distance weighted interpolation. In addition, this paper has also studied the classical ionosphere models which were commonly used by single frequency users, including Klobuchar model, NeQuick model, NTCM-BC model,then got some conclusions. The primary researching contents of this paper are as follows:1. Introduced the layering structure of the ionosphere and the previous researches on it, and the influences of the ionosphere on the GPS pseudorange observations on P or C/A code and carrier phase observations L1 or L2 band;2. Carried out a detailed expatiation of principles and methods of calculating the vertical electron content of the ionospheric pierce point by using GPS dual frequency observations, including the calculation of latitude and longitude of the IPP, the establishment of observation equations, and produced the specific calculation steps. Finally, got program to the approach of calculating the vertical electron content of the IPP by using GPS dual frequency observations.3. Introduced the Kriging method of the Geostatistics to the GPS ionospheric fields, found a model which was suitable for the ionospheric electron content data.Compared the IDW method, Kriging method with the 15 th order spherical harmonics model of IGS. And through experiments to verify the Kriging method is better than the IDW method.4. Compared Klobuchar model, NeQuick model and NTCM-BC model, then got a conclusion that the NTCM-BC model and NeQuick model are better than the Klobuchar model in some respects.