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针对卫星光学系统在轨工作时机上相机和星敏感器受温度影响其相互间夹角会出现变化而影响相机指向精度的问题,利用数字摄影测量方法在试验室常温常压环境下对结构件进行了热变形测量试验。通过拍摄组合体结构件上相机和星敏器的特定表面标志点,计算了坐标值,拟合了光轴矢量。以相机之一为基准计算法线矢量差和不同工况下矢量差的变化,即夹角在各工况下的变形量。试验按照试件温度状态分为4个工况、20个子工况。测量结果显示最大变形量为227.9″,测量精度优于13.9″;与有限元分析比对,两者在各子工况的变化趋势一致,均方值为30.4″。得到的结果表明,通过用合理选择拍摄位置、剔除粗大误差以及将编码标志点作为公共点进行坐标系转换等方法,可以提高数字摄影测量系统的测量精度,满足卫星结构件热变形测量的需求。
Aiming at the problem that the angle between the camera and the star sensor affected by the temperature of the satellite optical system on the orbit of the satellite optical system will affect the pointing accuracy of the camera, digital photogrammetric methods are used to test the structure at room temperature and normal pressure in the laboratory Thermal deformation measurement test. The coordinates were calculated and the optical axis vectors were fitted by photographing the specific surface markers of the camera and the star sensor on the structure of the assembly. Based on one of the cameras, the difference between the normal vector and the vector difference under different conditions is calculated, that is, the amount of deformation of the included angle under each working condition. The test is divided into four conditions and 20 sub-conditions according to the temperature of the test piece. The measurement results show that the maximum deformation is 227.9 “and the measurement accuracy is better than 13.9”. Compared with the finite element analysis, the trend of change in each sub-condition is the same with a mean square value of 30.4 ". The obtained results show that by using Reasonable choice of shooting location, excluding gross errors and code points as a common point coordinate system conversion, etc., can improve the measurement accuracy of digital photogrammetric systems to meet the needs of thermal deformation measurement of satellite structures.