光学测绘卫星星地相机夹角在轨实时定标方法

由于光学测绘卫星无地面控制点定位精度受星地相机夹角在轨变化的直接影响,因此针对现有星地相机姿态稳定度不高、星地相机夹角定标时间周期长的实际应用问题,提出了一种基于光学自准直原理的星地相机夹角星上实时定标方法。首先在相机载荷系统内部加装准直光源、光斑成像面阵等器件;然后通过光斑影像位置的变化求解出单个相机的主光轴变化;最后求解星地相机间夹角的变化。仿真实验表明,俯仰和横滚方向可获得0.1角秒量级的星地相机夹角定标精度。该方法无须地面定标场,不受外界因素影响,可以实现星地相机夹角的星上实时自主定标,具有良好的可行性和实用价值。

Method for real-time in-orbit calibration of angles for the optical surveying and mapping satellite

The positioning accuracy is directly affected by the change of the angle between star sensor and earth observation camera of the optical mapping satellite in the orbit, without the support of ground control point data. Aiming at the practical application problems of low attitude stability and the long calibration period of the earth observation camera, this paper proposes a real-time method for the calibration of the angle between star sensor and earth observation camera, based on the self-collimation method. First, we install collimated light sources, the spot imaging array and other devices inside the satellite load system. Then, we convert changes in the camera's optical axes into changes in the spot images. Finally, the angle variation between the cameras’ optical axes can be solved. Simulation analysis shows that this method can obtain the calibration accuracy of 0.1 arc second-time in both the pitch angle and roll angle. This method requires no ground calibration field and it is not affected by external conditions. It can realize real-time autonomous calibration in-orbit. This method has a good feasibility and practical value.