嫦娥三号(CE-3)着陆器的高精度定位具有重要的工程意义和科学应用价值.本文研究基于美国月球侦察轨道器(lunar reconnaissance orbiter,LRO)窄角相机(narrow angle camera,NAC)高分辨率月球遥感影像进行CE-3着陆点高精度定位的方法,并利用月面绝对控制点进行精度验证.收集历年来CE-3号着陆区和月球表面棱镜点的LRO NAC数据,利用精化后的轨道、姿态及相机参数等数据建立LRO NAC的严密成像几何模型,通过严密成像几何模型的初始点位预测、人工量测和高精度匹配等方式,获取影像上着陆点和月面激光测距反射棱镜点的影像坐标.用DEM辅助单像测图方法分别对CE-3着陆点和各棱镜标志点进行定位解算,将棱镜点的定位结果与地面观测的高精度定位值对比进行精度评价.利用本文方法,得到CE-3着陆点定位坐标为北纬44.1219?,西经19.5113?.
High precision positioning of Chang'E-3 lunar lander is of great importance for the mission operations and relevant scientific investigations. In this research, we calculate the location of Chang'E-3 lander using Lunar Reconnaissance Orbiter(LRO) narrow angle camera(NAC) images and validate the precision with the Lunar Ranging Retro Reflectors(LRRRs). First, we pinpoint the Chang'E-3 lander and other landmarks(LRRR etc.) on multiple LRO NAC images by manual interpretation and high-precision image matching. Then the geodetic coordinates are derived from the image coordinates with the rigorous sensor models established with the refined orbiter positions and attitudes from NAIF SPICE kernels. Finally, the average geodetic coordinates are calculated and considered as the locations of Chang'E-3 and other landmarks. As a result, the location of Chang'E-3 is determined to be 44.1219?N, 19.5113?W using 14 LRO NAC images. The five LRRRs with high-precision absolute locations available are used as check points to evaluate the poisoning errors. The results show that the location accuracy can reach 20 m with a single LRO NAC image, and positioning the lander using multiple images reduces random errors and provides better accuracy than that using a single image.