Difference Analysis and Improvement of Ionospheric TEC Modeling of GPS and GLONASS

Abstract:

To improve the total electron content (TEC) accuracy retrieved by multimode GNSS(global navigation satellite system), this paper addresses the distinctions of TEC retrieved from GPS(global positioning system) and GLONASS（global orbiting navigation satellite system） using global and Chinese GNSS stations. It indicates that TEC retrieved from GPS is more accurate than that from GLONASS. The regional model results in China show that the GPS/GLONASS TEC correlation coefficients increase with latitude and GLONASS underestimates TEC compared with GPS. The difference has the relationship with constellation configuration, signal system and orbit design difference. The TEC difference has latitude and local time dependency, and critical frequency of F2 layer (foF2) has similar phenomena with local time and geographic latitude dependency. Based on the study, a newly weighting function is designed for GLONASS measurements. The results show that the method will improve the bias and the root mean square (RMS) by 15% and 20% respectively in GPS and GLONASS combine mode.