Precision Analysis of Clock Products Data from iGMAS Analysis Centers

With the full accessibility to the BeiDou navigation satellite system (BDS) and the further development of the international GNSS monitoring & assessment system (iGMAS), it is of great significance to study the satellite atomic clock related technology with the iGMAS clock bias data. Presently, the analysis focuses on global positioning system (GPS), but the iGMAS rapid/ultra-rapid clock bias products have not been comprehensively evaluated. Thus the clock bias precision analysis strategy and precision assessment index were devised. The final precise clock bias data were taken from the international GNSS service analysis center (IGS) and three analysis centers under the programs of the multi-GNSS experiment (MGEX). The data were then comprehensively assessed in terms of precision using the median-based two-step gross error detection method and the second difference eliminating system bias method. The precision index of the iGMAS rapid/ultra-rapid clock bias products was further analyzed. As revealed in the test results, the iGMAS final precise clock bias products were as accurate as indicated by the data from the MGEX analysis centers. The observed-half precision of rapid and ultra-rapid clock bias products was in hundred-picoseconds, while the predicted-half precision of ultra-rapid clock products was within two nanoseconds. In the end, the miss rate of data regarding the iGMAS clock bias products is discussed to provide reference for practical applications.