Center of mass estimation of Tiangong-2 spacecraft using GNSS measurement [基于GNSS测量的天宫二号质心确定]

作者：Jin Z.; Wang W.^*; Liu J.

来源：Journal of Beijing University of Aeronautics and Astronautics, 2021, 47(4): 802-813.

DOI：10.13700/j.bh.1001-5965.2020.0019

• Center of Mass (COM) estimation
• Empirical acceleration
• Laser ranging
• Tiangong-2
• Yaw-steering attitude mode

Due to fuel consumption of orbital maneuvers, payloads' load and separation, and the release of small satellite, the Center of Mass(COM)of Tiangong-2 space laboratory moves. To solve this problem, a reduced orbit dynamic determination and COM estimation method is given based on Global Navigation Satellite System (GNSS) measurement data in this paper. Fuel consumption is the main reason for the COM of Tiangong-2 moves. The COM mainly moves along the X-axis of Tiangong-2 body-fixed coordinate system. The COM estimation and precise orbit determination of Tiangong-2 are performed using GNSS measurement data. And in a three-axis earth-pointing stabilization attitude mode, the orbit determination results are not sensitive to the displacement of COM in the X-axis of Tiangong-2 body-fixed coordinate system since the X-axis of Tiangong-2 body-fixed coordinate system coincides with the tangential direction of the orbit. However, in a yaw-steering mode, the X-axis of Tiangong-2 body-fixed coordinate system has a large projection on the orbital normal direction, which makes the displacement of COM in the X-axis of Tiangong-2 body-fixed coordinate system have a greater impact on the precision orbit determination results based on GNSS measurement calculation. And the qualitative and the quantitative analysis results show that the COM estimation is feasible in a yaw-steering attitude mode. Compared with the results without considering COM estimation, the Tiangong-2 measurement data calculation results considering COM estimation show that the empirical accelerations which represent orbital dynamics modeling error in the radial, tangential and normal directions are reduced by 62%, 50% and 65%, respectively, and the standard deviation of post-residuals of the carrier phase is reduced by 0.04 cm. Besides, the comparison accuracy of precision orbit data and the global laser ranging improves by 0.86 cm. The method proposed in this paper can be applied to COM estimation of the large-scale low-earth-orbit spacecraft.

• 单位
  中国科学院大学