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嫦娥三号(CE-3)探测器成功实现了我国首次月球软着陆,对巡视器和着陆器进行高精度定位是保障两器顺利完成月面探测任务的必要前提.本文首先对CE-3月面工作段的测量方式、各观测量测量模型以及运动学统计相对定位方法进行讨论.其次对着陆器进行定位并对定位精度进行评价,得到着陆器坐标为:44.1206°N,-19.5124°E,高程-2632 m(相对1737.4 km月面),通过与月面数字高程模型以及NASA探测器LRO的航拍结果比较,定位差异优于50 m,分析表明VLBI数据对提高着陆器定位精度有显著贡献.最后,利用同波束VLBI数据进行月面巡视器与着陆器的相对定位.与视觉定位方法相比,本文所用的基于地基观测量的运动学统计定位法不受着陆器可视范围限制,且定位精度不随两器距离增加而降低.计算结果表明,在现有的测量条件下,使用纳秒量级的VLBI差分群时延数据,两器相对定位精度在百米;使用皮秒量级的VLBI差分相时延数据,并在定位过程中进行模糊度解算,可以实现米级的月面双目标的相对定位,具有重要意义.
The CE-3 detector successfully achieved the first lunar soft landing in China, and the high-precision positioning of the navigator and lander is necessary prerequisite to ensure the successful completion of the Lunar exploration mission.This paper first analyzes CE- The measurement mode of the surface work section, the measurement model of each observation and the relative positioning method of kinematic statistics are discussed.Secondly, the positioning of the lander and the evaluation of the positioning accuracy, the lander coordinates are obtained as follows: 44.1206 ° N, -19.5124 ° E, Elevation -2632 m (relative to 1737.4 km lunar surface). The positioning difference is better than 50 m by comparing with lunar elevation model and NASA LRO. The analysis shows that VLBI data can significantly contribute to the improvement of lander positioning accuracy. Finally, the relative position of lunar patrol lander and lander is compared with the same beam VLBI data.Compared with the visual positioning method, the kinematic statistic positioning method based on ground-based surveying used in this paper is not limited by the scope of the lander, The accuracy does not decrease with the increase of the distance between the two instruments.The calculation results show that under the existing measurement conditions, the VLBI differential group delay data of nanosecond magnitude is used, and the relative positioning accuracy of the two instruments is in a hundred meters Using picosecond VLBI differential phase delay data and resolving the ambiguity in the positioning process, it is of great significance to realize the relative positioning of the rice-level lunar dual targets.