Accuracy Analysis of GNSS Broadcast Ionospheric Model

In order to verify and evaluate the correction precision of the model and parameters of Klobuchar 8 parameters (k8) and Klobuchar 9 parameters (k9) of BDS global ionospheric delay correction model (BDGIM), and the GPS-k8 ionospheric correction model as well as the NeQuick correction model of Galileo, this paper uses GNSS radio ionospheric correction parameters provided by iGMAS and global ionospheric grid data of the CODE to analyze the ionosphere model correction accuracy. Data analysis shows that in China and the surrounding areas, the correction accuracy of BDS-k9 model and parameters is basically the same as that of GPS-k8. The correction accuracy of BDS-k9 model and parameters is obviously better than that of BDS-k8 model, and the optimal RMS of BDS-k9 is 0.72 m. At 20 degrees to 45 degrees mid-latitude areas, GPS-K8 correction precision is highest, the optimal RMS of GPS-K8 is 0.705 m. However, the correction accuracy at southern hemisphere is not well. The global ionosphere correction results of Galileo which uses the NeQuick2 model are smooth and the correction accuracy in northern and southern hemispheres is similar.