全球测图与境外目标定位等任务对航天遥感几何定标与定位精度的要求越来越高。当前像点量测误差与地面控制点精度不匹配,影响了航天传感器定标结果的可靠性。点源靶标在航天影像中具有良好的几何形态,能够为几何定标任务提供精确的像点坐标。对模拟点源靶标影像进行了解算,得到其像点误差在0.04 pixel以内,均方根误差仅为0.01 pixel,优于当前测量软件及人工选点精度。检验了不同像点测量误差对定标和定位结果的影响,结果显示,以点源靶标作为控制点时,定标参数的解算结果和定位精度均优于使用传统控制点的结果;在缺少控制点的情况下,增加两个点源靶标能够使定位误差降至分米量级。点源靶标能够有效提高几何定标与定位结果的精度,并有潜力发展成为新一代几何定标工具。

Tasks such as global mapping and overseas target positioning have the higher and higher requirements for space remote sensing geometric calibration and positioning accuracy. The current measurement error of the image pixel coordinates does not match the accuracy of the ground control points (GCP), which limits the reliability of the calibration results of the space sensors. The point source target has a good geometry in the aerospace image and can provide precise pixel coordinates for the geometric calibration task. In this paper, the pixel coordinates of the simulated point source images are solved, and the errors the pixel coordinates are below 0.04 pixel and the root mean square error is only 0.01 pixel, superior to those by the current measurement software and the manual selection. In addition, the effect of pixel measurement error on the calibration and positioning results is examined. The results show that the use of point source target as GCP can make the calibration parameter and positioning accuracy better than those using the traditional GCPs. In the absence of GCPs, adding two point source targets can reduce the positioning error to the decimeter level. The point source target can effectively improve the accuracy of geometric calibration and positioning results and has the potential to develop into a new generation of geometric calibration tools.