Development of XNAV algorithm and cycle ambiguity resolution

Li Qiao*, Jian Ye Liu, Guang Lou Zheng, Zhi Xiong

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


The X-ray pulsar based navigation (XNAV) is a new celestial navigation concept for the spacecraft. The autonomous orbit determination algorithm using pulse phase difference of X-ray pulsars is investigated for navigation satellite. The transmission time of the X-ray pulse from the satellite to the solar system barycenter is analyzed. The measurement equation of the satellite position is described with the pulse phase difference between the satellite and the solar system barycenter. The extended Kalman filter, which incorporates the navigation satellite dynamics and the pulse phase-based measurements, is developed to estimate the satellite orbit. Considering that the satellite position predicted by satellite orbit dynamics is accurate, the predicted satellite position is utilized to determine the cycle ambiguities, and this method is tested feasible. Simulation results demonstrate that this navigation algorithm can provide absolute position of the navigation satellite in the Earth centered inertial frame.

Original languageEnglish
Pages (from-to)1460-1465
Number of pages6
JournalYuhang Xuebao/Journal of Astronautics
Issue number4
Publication statusPublished - Jul 2009


  • Autonomous navigation
  • Cycle ambiguity
  • Phase difference
  • Satellite
  • X-ray pulsar


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