Comparison of IRI-2012 and Rapid GIMs With GNSS-Derived TEC Over China

摘要

The ionospheric delay is one of the predominant errors limiting the accuracy of Global Navigation Satellite Systems (GNSS), especially for single-frequency users. Meanwhile the IGS (International GNSS Service) Ionospheric Working Group and International Reference Ionosphere play an essential role in promoting ionospheric studies. This contribution will analyze the performance of IGS rapid Global Ionospheric Maps (GIMs) and the latest version International Reference Ionosphere model IRI-2012 aiming to provide more valid ionospheric correction in China. Three pairs of stations from CMONOC (Crustal Movement Observation Network of China) in 2013 are employed to analyze the discrepancy between rapid GIMs, IRI-2012 and GNSS-derived TEC. Results show that the rapid GIMs and IRI-2012 have distinct difference from GPS-derived TEC both in daytime and nighttime. In terms of rapid GIMs, the performance over IGS stations is generally better than those are non IGS stations, with pronouncedly better accuracy of about 20 and 50 % in daytime and nighttime respectively with respect to GNSS-derived TEC. Moreover, IRI-2012 is likely to overestimate TEC value in daytime, and underestimate TEC value in nighttime.