针对基于视觉的航天器相对导航问题,利用对偶数推导并给出了航天器相对耦合动力学方程,该方程一体化描述了追踪航天器相对于目标航天器的姿态运动和轨道运动,且考虑了由非质心点引起的相对姿态与相对轨道之间的耦合影响.在对偶代数的框架内,统一描述了目标航天器上的特征点和特征线,并基于特征点、线在像平面的投影建立了多特征融合的单目视觉测量模型.最后通过对系统状态方程以及测量方程的线性化,应用迭代扩展卡尔曼滤波(IEKF)算法对非质心点的相对运动状态进行了估计.仿真结果表明,本文的算法能够对航天器非质心点的相对运动状态进行较高精度的估计.%A vision-based relative navigation algorithm for spacecraft is addressed in this paper. Based on the dual number, a relative coupled dynamic equation is derived which can describe both the rotational motion and the translational motion of the chaser spacecraft relative to the target spacecraft, and the effect of rotation-translation coupling due to the point deviating from the center of the mass of the spacecraft. In the dual algebra, the feature lines and points are described uniformly. A multi-cue-based measurement model is proposed using the 2-D images of 4he feature lines and points fixed on the target spacecraft, and the iterated extended Kalman filter (IEKF) is applied to estimate the relative state between the points off the center of the mass of the two spacecraft. Numerical simulations are performed to demonstrate that the proposed approach can provide an accurate estimation of the relative position and attitude of points deviating from the center of the mass of the spacecraft.
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