基于数字检校场的“天绘一号”卫星在轨几何定标

On-orbit Geometric Calibration Based on Digital Calibration Field for TH-1 Satellite

为了提高"天绘一号"卫星在轨几何定标的效率和精度,文章提出一种利用数字检校场(数字正射影像和数字高程模型)、基于简化的卫星几何定位模型的在轨几何定标方法。该方法利用卫星影像与数字正射影像自动匹配得到同名点的平面位置、由数字高程模型获得高程位置,得到大量地面控制点,再基于简化内外方位元素误差补偿模型,利用多轨数据求解系统误差改正参数,实现了几何定标。精度检测表明,经过定标后,无控定位平面误差由初始约100m,提升至10.5m(一倍中误差);基于内方位定标结果,文章实现了基于虚拟线阵算法的高分影像子条带合成和多光谱配准,并实现了优于0.3像素的内部符合精度。

In order to improve the accuracy of TH-1 satellite image and efficiency of the geometric calibration, the article proposed a method of geometric calibration based on a simplified geometric model and digital calibration fields（digital orthophotos map and digital elevation models）. In the method, the corresponding ground control points were obtained by auto-matching the raw image with DOM and fetching the height value by DEM, then the coefficients of error compensation model were solved by the simplified model. The test results demonstrated that the accuracy of position with no control points improved from worse than 100 m to 10.5 m（1 sigma）. Based on the result of interior orientation calibration, the virtual line algorithm was implemented in the sub-chip image combination of the high resolution camera and multi-band camera, with the internal accuracy of better than 0.3 pixel.