多视场星敏感器数学模型与精度分析

多视场星敏感器与传统单视场星敏感器相比不仅具有更高的可靠性和自主性,也具有更高的精度和动态性能,是未来星敏感器发展的重要趋势之一.为获得最佳性能,需要对多视场星敏感器的视场大小和布局进行优化.为此,首先建立了多视场星敏感器的数学模型,重点介绍了星点成像和姿态计算.然后推导了多视场星敏感器测量精度的数学表示,分析了影响精度的因素.通过仿真分析了多视场星敏感器视场大小和布局对各因素和精度的影响.仿真结果表明,视场大小对星敏感器精度的影响取决于星敏感器的运动情况,当角速度较小时,视场越小,精度越高;当角速度较大时,视场越大,精度越高.而各视轴相互正交的视场布局下,多视场星敏感器的测量精度最高.

Modeling and accuracy analysis for multiple heads star tracker

As an important trend in the future, multiple heads star tracker is not only of higher reliability and autonomy, but also of higher precision and dynamic performance than classical star tracker. In order to achieve the best performance, system parameters optimization for multiple heads star tracker is needed. A mathematical model of multiple heads star tracker was developed firstly, particularly on the star imaging and attitude determination. Then an analytic expression of accuracy was deduced, and the error sources affecting the attitude accuracy were analyzed. Finally, the effects of the field of view and the relative alignment on the accuracy were discussed systematically based on the simulation results. The results show that the relation between field of view and accuracy depends on the angular rate. The accuracy is improved with smaller field of view at lower angular rate, while with larger field of view at higher angular rate. And multiple heads star sensor reaches the highest precision when the boresights are orthogonal.