基于平行光管的星敏感器焦平面离焦距离检测设备设计及其误差分析

Design and Error Analysis of Detection Device of Focal Plane's Defocusing Distance of Star Sensors Based on Collimator

在星敏感器中,使用离焦成像的方式实现对恒星的成像,成像质量直接影响着测量定位精度。而星敏感器光学系统和图像传感器之间的离焦距离是寻找最优成像的重要参数。为了准确测得此离焦距离,设计了基于平行光管的星敏感器焦平面离焦距离检测设备,并针对设备设计原理中影响检测精度的各项因素进行误差分析。首先,在检测原理公式的基础之上,给出主要设计参数。其次,结合检测原理公式分析主要影响因素,即平行光管焦距误差、星敏光学系统焦距误差和直线位移台运动分辨率,并针对不同取值范围进行了仿真,验证了设计参数的理论合理性。

In the star sensor, the image of the star is realized by the way of the off-focal imaging, and the image quality of off- focal imaging directly affects the positioning accuracy. The defocusing distance between the optical system of the star sensor and the image sensor is the important parameter to find the optimal imaging. To accurately measure the defocusing distance, an equipment for detecting the focal plane＇s defocusing distance of the star sensor is designed, and the factors affecting the accuracy of the detection of the focal plane＇s defocusing distance of the star sensor are analyzed. Firstly, the main design pa- rameters are given based on the principle formula of detection. Secondly, the main influencing factors are analyzed by combi- ning with the formula,including the collimator＇s length focus error, the star sensor＇s optical system focal length error and the motorized linear translation stage＇s motion resolution, and the simulation is carried on in view of the scope of their respective different values, to verify the theoretical rationality of the design parameters.