基于天文观测的相机标定及姿态测量技术研究

Camera Calibration and Attitude Measurement Technology Based on Astronomical Observation

为利用相机进行天文观测以实现高精度的相机姿态测量,必须先对相机参数进行精确标定。针对传统相机标定方法工作距离有限的问题,提出了以恒星为控制点的相机标定方法,根据球面天文学方法计算观测时刻控制点的世界坐标,利用摄像测量原理建立了恒星观测模型,求解相机的内外参数并分析了误差因素。实验结果表明,该标定方法在不依赖于精密、复杂的外部设备情况下可达到较高精度,并具有较强的抗噪声能力。将标定结果用于天文观测并求解相机姿态,航向角和俯仰角的解算重复性优于10″,能够满足高精度姿态测量的需求。该方法可进一步推广应用于星敏感器的标定。

To realize high precision attitude measurement by means of astronomical observation with a camera, it is quite necessary to calibrate the parameters of the camera accurately. A camera calibration method is presented based on astronomical observation to solve the problem that the traditional calibration methods can only work effectively in a limited distance. The world coordinates of control points at the measuring time are calculated by using the spherical astronomy method. A star observation model is established according to the photogrammetric principle, both the external and intrinsic parameters of the camera are obtained, and the calibration precision is also analyzed. The experimental results indicate that the calibration method can achieve a good precision without the aid of precise and complex equipment, and the method performs also well when noise exists. Finally, the calibration result is adopted to work out the attitude of the camera, and the obtained repeatability accuracy of yaw and pitch angle is better than 10＂. This method can be applied to the calibration of star sensor.