GPS Solutions

, Volume 21, Issue 3, pp 1251–1263 | Cite as

Robust combination of IGS analysis center GLONASS clocks

  • Kangkang Chen
  • Tianhe XuEmail author
  • Yuanxi Yang
Original Article


The International GNSS Service (IGS) Analysis Centers (ACs) generate precise GNSS products by integrating tracking data from globally distributed IGS stations. The ACs’ products are further processed and combined for the positioning, navigation and timing users. We propose a robust least squares estimation for combining GLONASS clock products. Besides the difference in clock reference, systematic errors exist in the clock differences between different ACs, which show a linear trend and are completely removed. The clock combinations utilizing the final, rapid and ultra-rapid products of the IGS ACs were implemented in this study. The results of clock validation show that the agreement and stability of the newly generated combination products are better than those of most ACs. Furthermore, the impact of the different clock combination products on precise point positioning (PPP) is analyzed. Compared to the results of PPP using the products generated by the traditional combination strategy, the repeatability of GLONASS static PPP using the new clock combinations is 2.31, 2.95, and 5.62 mm, an improvement by 26.7, 28.9 and 20.6% in N, E and U respectively. The average RMS of GLONASS kinematic PPP using the new clock combinations is 1.20, 1.47 and 3.01 cm, an improvement by 67.5, 71.9 and 70.3% in N, E and U respectively. The improvement of the proposed strategy on PPP results is significant.


IGS GLONASS MGEX Clock combination Systematic error compensation Robust least square estimation Precise point positioning 



The continuing contribution of many individuals from many organizations around the world to maintaining the high quality of IGS products is gratefully acknowledged. The research was supported by National Natural Science Foundation of China (Grant Nos. 41574013, 41174008, 41374019) and National High-tech Research and Development Program of China (2016YFB0501700, 2016YFB0501701). The authors are grateful for the comments of reviewers, which helped to improve the manuscript significantly.


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Copyright information

© Springer-Verlag Berlin Heidelberg 2017

Authors and Affiliations

  1. 1.College of Geology Engineering and GeomaticsChang’an UniversityXi’anChina
  2. 2.Institute of Geodesy and PhotogrammetryETH ZurichZurichSwitzerland
  3. 3.Institute of Space ScienceShandong UniversityWeihaiChina
  4. 4.State Key Laboratory of Geo-information EngineeringXi’anChina
  5. 5.Xi’an Research Institute of Surveying and MappingXi’anChina

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