针对嫦娥三号极紫外相机影像由于缺少控制点约束而无法沿用地球遥感影像几何定位方法的现状, 研究了极紫外相机的工作原理、涉及的坐标系统及其转换关系, 提出了一种基于星上遥测参数和严格坐标转换关系的几何定位方法, 进行了影像数据几何定位及定位精度分析.研究结果表明, 该方法能够解算影像拍摄时刻极紫外相机光轴在太阳磁层坐标系中的指向, 以及着陆器在该坐标系中的位置, 精确定位影像中地球质心的位置, 校正相机光轴指向在原始影像中对应的位置, 确保极紫外相机探测数据的科学应用价值, 实现嫦娥三号空间环境探测的科学目标.

Geometric positioning methods for earth remote sensing images cannot be used for Chang’E-3 (CE-3) moon-based Extreme Ultraviolet Camera (EUVC) images because of lack of control points. According to this present situation, working principle and related coordinate systems for EUVC were introduced, and a geometric positioning algorithm was proposed for EUVC observations based on telemetry parameters and strict coordinate transformation relationship. Algorithm of geometric positioning was researched and positioning accuracy was evaluated. The results show that the space pointing of EUVC optical axis and CE-3 lander’s position in Solar Magnetic System at image acquisition epochs can be calculated by the proposed algorithm for high-precision geocentric position. Geocentric position results can also be used to correct the original images to ensure the reliability of the EUVC observations and to realize CE-3’s scientific objective of the space environment detection.