Acta Geodaetica et Cartographica Sinica ›› 2025, Vol. 54 ›› Issue (9): 1596-1607.doi: 10.11947/j.AGCS.2025.20250055

• Geodesy and Navigation • Previous Articles     Next Articles

Kalman filter-based satellite clock bias prediction algorithm with frequency difference estimation correction

Cong SHEN1,2(), Guocheng WANG1(), Lintao LIU1, Huiwen HU1,2, Zhiwu CAI3   

  1. 1.State Key Laboratory of Precision Geodesy, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430077, China
    2.University of Chinese Academy of Sciences, Beijing 101408, China
    3.Beijing Satellite Navigation Center, Beijing 100094, China
  • Received:2025-02-13 Revised:2025-07-08 Online:2025-10-10 Published:2025-10-10
  • Contact: Guocheng WANG E-mail:shencong@apm.ac.cn;guocheng96@apm.ac.cn
  • About author:SHEN Cong (1996—), male, PhD candidate, majors in clock bias processing and analysis. E-mail: shencong@apm.ac.cn
  • Supported by:
    The National Natural Science Foundation of China(42074011);The Key Projects Deployed by the Major Scientific and Technological Mission Bureau of the Chinese Academy of Sciences(T24Y6303)

Abstract:

Satellite clock bias prediction is of great significance for time synchronization, real-time positioning, and autonomous navigation, and its accuracy directly affects the service quality of navigation systems. The traditional Kalman filter model (KFM) is widely used in clock bias prediction because of its minimum variance estimation characteristics, which enable it to obtain optimal estimates of time difference, frequency difference, and frequency drift. However, KFM does not explicitly model the periodic terms in clock bias, resulting in periodic fluctuations in the estimated values of time difference, frequency difference, and frequency drift. This periodic estimation bias increases the prediction error of KFM and further amplifies it over time. To address this issue, this paper proposes an improved Kalman filter model (IKFM) based on frequency difference estimation correction. This model first identifies the periodic terms in the frequency difference estimates through spectral analysis and fits their parameters using least squares. Then, periodic fluctuations are subtracted from the estimated values to eliminate the interference of periodic terms on the state estimation. Finally, the time difference is extrapolated based on the corrected frequency differences. The experimental results based on GPS clock bias data show that, compared with KFM, IKFM reduced the error in 1~24 h predictions by up to 32.14%; and compared with the gray model, quadratic polynomial model, and spectral analysis model, IKFM showed the best accuracy and stability for all prediction durations. By effectively suppressing periodic term interference, IKFM provides a reliable solution for high-precision satellite clock bias prediction, especially for spaceborne atomic clocks with significant periodic fluctuations.

Key words: satellite clock bias prediction, Kalman filter, prediction accuracy, atomic clock state estimation, periodic terms

CLC Number: