Assessment Of Code Gim Over China

Since IGS ionosphere working group(IONO_WG) was established in 1998, ionosphere products have been supplied routinely with the form of IONEX maps. The final IONEX map has the precision of about 2-8TECu in the whole world given by the ionosphere validation center. Due to at most six IGS GPS stations in China used to retrieve global ionosphere model(GIM), the precision of the GIM applied to China is not the same as to Europe and USA, which has to be evaluated for all kinds of users in this area. The CMONOC(Crustal Movement Observation Network of China) has been constructed with 260 GPS stations and other instruments, which can provide very nice conditions for us to model the ionosphere more precisely in China area. In this article, we choose about 200 GPS stations from CMONOC and several hundreds of IGS stations over different periods of 2011, which is in the rising period of sun activity, to model the global ionosphere, and GIM from CODE in china region can be assessed with this more exact model. By analysis on the applied precision of CODE GIM over China, we have a conclusion: 1) there is a bias of 2-4TECu, RMS of 2-4TECu, and STD of 1-2TECu under the magnetic quiet circumstances and the bias is about 5.1TECu, RMS is about 5.7TECu and STD is about 2.4TECu under the magnetic disturbances circumstances. 2) for the situations at the specific time of ionosphere changes within one day( local time 14h and 22h), bias of the former situation is in the range of 2-4TECu while that of latter is in the range of 2-5TECu under normal circumstances and bias of the former situation is about 7.6TECu when that of latter is about 4.9TECu.