Comparison of Methods on Computing Ionospheric Delays in GNSS System Time Offset Determination

摘要

Ionospheric delay error is one of the main factors that have significant impact on GNSS system time offset determination. Two methods are adopted to calculate the ionospheric delays in the monitoring of the GNSS system time offset. The first one is Total Electron Content (TEC) map provided by International GNSS Service (IGS) and the other one is the dual-frequency measure correction. The different effects of these two calculating methods are compared and analyzed in this paper. The results show that the ionospheric delays are corrected using dual-frequency observation is better than using the IGS TEC MAP. The monitoring results of the GPS/GLONASS system time offset compared with GPS/GLONASS system time offset published by Circular T, the accuracy of the former one is increased by 15 % than the latter one.