College of Opto-Electronic Science and Engineering, National University of Defense Technology, Changsha 410073, China.
Sensors (Basel). 2018 Sep 14;18(9):3106. doi: 10.3390/s18093106.
The integration of a star tracker and gyroscope units (GUs) can take full advantage of the benefits of each, and provide continuous and accurate attitude information with a high update rate. The systematic error calibration of the integrated system is a crucial step to guarantee its attitude accuracy. In this paper, a comprehensive calibration method for the star tracker and GUs integrated system is proposed from a global perspective. Firstly, the observation model of the predicted star centroid error (PSCE) with respect to the systematic errors including the star tracker intrinsic parameter errors, GUs errors and fixed angle errors is accurately established. Then, the systematic errors are modeled by a series of differential equations, based on which the state-space model is established. Finally, the systematic errors are decoupled and estimated by a Kalman filter according to the established state-space model and observation model. The coupling between the errors of the principal point and subcomponents of the fixed angles (i.e., Ψ x and Ψ y ) is analysed. Both simulations and experiments indicate that the proposed method is effective at estimating the systematic errors of the star tracker and GUs integrated system with high accuracy and robustness with respect to different star centroid accuracies and gyroscope noise levels.
星敏感器和陀螺组件（GUs）的集成可以充分利用它们各自的优势，提供具有高更新率的连续、准确的姿态信息。集成系统的系统误差校准是保证其姿态精度的关键步骤。本文从全局角度出发，提出了一种星敏感器和 GUs 集成系统的综合校准方法。首先，准确建立了考虑星敏感器固有参数误差、GUs 误差和固定角度误差等系统误差的预测星心像点误差（PSCE）观测模型。然后，基于该模型，通过一系列微分方程对系统误差进行建模，建立状态空间模型。最后，根据建立的状态空间模型和观测模型，通过卡尔曼滤波器对系统误差进行解耦和估计。分析了主点误差和固定角度子分量（即 Ψx 和 Ψy ）误差之间的耦合。仿真和实验结果均表明，该方法能够有效估计星敏感器和 GUs 集成系统的系统误差，具有较高的精度和鲁棒性，适用于不同的星心像点精度和陀螺噪声水平。
