On-Orbit Thermal Deformation Impact on Attitude Offset and Angular Velocity Reconstruction: Insights From Multisatellite Tracker Data Combination and Temperature Correction

During on-orbit operations, star trackers (STRs) are vulnerable to thermal deformations caused by the space environment, which can lead to shifts in the interboresight angles (IBA), severely affecting attitude measurement accuracy and degrading the quality of gravity satellite observation data. To address the shortcomings of traditional attitude calibration methods that overlook thermal deformation effects, this study presents an on-orbit thermal deformation attitude reconstruction method based on multi-STR joint processing. By analyzing the correlation between STR noise characteristics and temperature, a three-axis noise distribution weighting matrix is developed, and a linear model is established for temperature-induced deviations in the interboresight angle. The weighted least-squares method is employed to combine multi-STR attitude data and compute the optimal attitude quaternion, enabling high-precision angular velocity reconstruction. Experimental results demonstrate that after thermal deformation correction, the average interboresight angle deviation of the STR is reduced to below 8.87 arcseconds, with a standard deviation (std) of less than 0.008 arcseconds. The three-axis angular velocity noise level decreases by approximately two orders of magnitude, with a total std improvement of 0.28 orders of magnitude. The accuracy of the Y-axis improves by a factor of about 6. Furthermore, the logarithmic quaternion Hermite hypersurface interpolation method ensures the continuity and smoothness of the attitude data. This study provides reliable technical support for high-precision attitude determination in satellite gravity missions, significantly enhancing angular velocity reconstruction accuracy, with consistent performance across all axes.