视线测量光学导航系统观测模型选取

在基于视线矢量观测的自主光学导航系统中，观测模型的非线性是影响导航精度的一个重要因素。通过定量计算观测模型的非线性强度，研究了视线测量光学导航系统测量模型的选取问题。文章基于透射投影模型的共线性方程，给出了两种视线矢量观测模型的导航测量方程及测量噪声统计特性。在扩展卡尔曼滤波框架内深入分析了观测模型非线性对导航性能的影响。并利用微分几何非线性曲率测量理论，定量比较了两种观测模型的非线性强度。最后以基于视线矢量观测的姿态确定系统为例，仿真验证了非线性曲率测量与导航性能的一致性，结果表明基于单位矢量观测模型的光学导航系统具有更高的估计精度和更快的收敛特性。

Selection of the Measurement Model for Line-of-sight Observation Based Optical Navigation System

In the autonomous optical navigation system based on line-of-sight vector observation, the nonlinearity of measurement model is an importance factor which influences the navigation accuracy. By quantitatively calculating the degree of nonlinearity, the selection of measurement model for line-of-sight observation based optical navigation system was studied. First, navigation measurement equations and measurement noise statistics of two line-of-sight measurement models were proposed based on the perspective projection colinearity equations. Next, the effects of measurement model nonlinearity on the navigation performance were thoroughly analyzed within the framework of the extended Kalman filter. Then, the measures of nonlinearity of two measurement models using the differential geometry curvature nonlinearity measure theory were compared. Finally, the simulation of attitude determination system from vector measurement was performed to confirm the proposed theory. The results show that the curvature nonlinearity measure magnitude and the filter performance are consistent and the optical navigation system based on the unit vector measurement model has higher precision and faster convergence properties than that based on the focal plane model.