Acta Geodaetica et Cartographica Sinica ›› 2025, Vol. 54 ›› Issue (3): 432-447.doi: 10.11947/j.AGCS.2025.20240248

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Consistency analysis of GNSS precise orbit and clock products based on globally unified coordinate frame

Xuexi LIU1(), Shouqing ZHU1(), Guo CHEN2, Kefei ZHANG1, Nanshan ZHENG1, Jingxuan LIU1   

  1. 1.School of Environmental and Spatial Informatics, China University of Mining and Technology, Xuzhou 221116, China
    2.GNSS Research Center, Wuhan University, Wuhan 430079, China
  • Received:2024-06-19 Online:2025-04-11 Published:2025-04-11
  • Contact: Shouqing ZHU E-mail:xuexiliu@cumt.edu.cn;TB23160012A51@cumt.edu.cn
  • About author:LIU Xuexi (1992—), male, PhD, associate professor, majors in GNSS high-precision positioning theory and methods. E-mail: xuexiliu@cumt.edu.cn
  • Supported by:
    The National Natural Science Foundation of China(42304015);The Natural Science Foundation of Jiangsu Province(BK20231087);China Postdoctoral Science Foundation(2024M753525);Jiangsu Province Youth Science and Technology Talent Support Project(JSTJ-2024-075);Open Research Foundation of the State Key Laboratory of Geodesy and Earth's Dynamics(SKLGED2024-3-7);Key Program of the National Natural Science Foundation of China(U22A20569)

Abstract:

Precise satellite orbit and clock offset are the key to fast fixing undifferenced ambiguity and achieving high-precision positioning services. The combination of orbit and clock offset product requires the unification of the spatial and temporal references between products from different analysis centers. This paper first solved for the Bursa coordinate transformation parameters to analysis the difference of similar transformation parameters between the precise satellite orbit products provided by different analysis centers, and statistically calculated the correlation coefficient between the similar transformation parameters of each system of analysis centers. Secondly, the benchmark differences of the precise clock products are analyzed and it is found that there is a significant constant bias in the linear transformation by estimating a set of linear transformation parameters using the clock data of all the satellites. The GPS and Galileo have a constant deviation of up to 200 ps, while the constant deviation of the GLONASS and BDS can reach 1000 ps and 2400 ps respectively. In this paper, we propose a method to eliminate this constant bias by estimating a set of linear transformation parameters for each satellite clock. Thirdly, this paper analyses the benchmark consistency between the orbital and station coordinates and the Earth's rotation parameter products. The correlation coefficients of most of the rotational components are more than 0.5, which indicates that the orientation benchmark differences are more consistent among the analysis centers. Finally, the consistency of orbit and clock is analyzed by making the double difference of orbit and clock. After removing the constant deviation of clock, most of the correlation coefficients of the double difference of orbit and clock of GPS and Galileo are more than 0.9, and the correlation coefficients of GLONASS and BDS are a little bit worse but the correlation coefficients also exceed 0.6. This indicates that the nonlinear parts of the second difference between the precision satellite orbits and the clock products are more consistent, showing a high degree of conformity between orbital changes and clock variations.

Key words: GNSS, precise satellite products, orbit and clock combination, unified coordinate frame, benchmark discrepancies analysis

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