A Novel Fitting Method for In-Flight Pointing Calibration of Large Spaceborne Parabolic Antennas

A novel fitting method for in-flight pointing calibration of large spaceborne parabolic antennas is proposed in this paper, including the model and the adjustment algorithm. For verification of the proposed method, two case studies of the 4.2m parabolic antenna onboard Queqiao and the 2.5m parabolic antenna on board Tianwen-1 orbiter is presented. Results show that the fitting curve coincides with the selected data very well. Compared with the classic method, the $\sigma_{0}$ of the post-fit residuals reduced by $4 \sim 5$ times, and the 3$\sigma$ precisions of the pointing error estimates are improved from 0.004/0.005 deg to 0.001 deg. This demonstrates the effectiveness and much better performance of the proposed method, which is more suitable for large spaceborne parabolic antennas’ in-flight pointing.