论文标题
关于超高精度星形跟踪器的星形质量估计和校准技术
On the Starspot Centroid Estimation and Calibration Technologies for the Super-high Accuracy Star Tracker
论文作者
论文摘要
A pointing accuracy better than 1"(3sigma) star tracker plays a significant role for the advanced scientific missions. This thesis makes a series of studies on the typical error sources associated with the positioning and calibration processes, such as the centroiding algorithm, detector noise, motion, focal length drift, variation of the center wavelength of stellar spectrum, the model error, etc., some works of which are listed as follows: IWCOG使用Cramer-Rao下限定理研究了算法的精度和效率。为了解决轨道校正过程中的问题，出现了一个出色的想法，即CRLB约束方法，以最大程度地减少一些误差源以实现此目标。他们的幅度和在不同的恒星场上的位置，QUEST算法升级。结果表明，该方法可以将态度测量精度统计上升10-20％，并且可以直接应用于各种类型的星星跟踪器。
A pointing accuracy better than 1"(3sigma) star tracker plays a significant role for the advanced scientific missions. This thesis makes a series of studies on the typical error sources associated with the positioning and calibration processes, such as the centroiding algorithm, detector noise, motion, focal length drift, variation of the center wavelength of stellar spectrum, the model error, etc., some works of which are listed as follows: IWCOG algorithm is studied for the characteristics of both the accuracy and efficiency. Using Cramer-Rao Lower Bound theorem,centified to have an approximate optimum property for signal with Possion noise and the optimum feature in case of Gaussian noise. In order to enhance the dynamic performance, the generallized dynamic compensation formula is derived to compensate out the error from motion. decoupling of three technical indicators including dynamic performance, pointing accuracy and attitude output rate. To solve the problems exhibited in the in-orbit correction procedure, a brilliant idea, known as the CRLB constraint method, is presented to minimize some small error sources. To fulfill this goal, the full CRLB constaint formulas are derived to build a budget to limit the in-flight parameters. Using this method the overall error are obtained, which in turn results in three significant inferences. The attitude determination process is further optimized, by giving different weights to each star according to their magnitudes and the position over different star field, the QUEST algorithm is thus upgraded. The results show that this method can improve the attitude measurement accuracy statistically by 10-20%. The theory and deductions can be directly applied to various types of star trackers, whether it is a super-high accuracy one, or a high dynamic one.
