Abstract: When using GPS dual frequency measurements to establish ionospheric models, the amount of satellites and distribution of pierce points would affect the accuracy. With the various navigation systems have been completed, it becomes an inevitable trend to establish ionospheric model with data from multi-systems. This paper studied on the establishment and data processing of ionospheric model based on the integration of GPS/GNSS systems, and developed a software of global ionospheric grid model based on GNSS, named IonoGim. Take the result of 001-031 days in 2010 as the example to analyze the influence for global ionospheric model by adding GLONASS data, we found that combining the data of GPS and GLONASS did not have a significant improvement for the result, on the contrary, the RMS at grids points were increased, which was caused by the weaker quality of GLONASS observations. However, the combining result corresponded better with CODE result. Besides, adding GLONASS observations to establish model cannot overcome the limitation of a bad accuracy over the marine area, therefore, how to improve the accuracy over the ocean still needs to be further studied.

Key words: VTEC, GPS/GLONASS, ionosphere model