VLBI相位参考成像方法用于玉兔巡视器精确定位  

Accurate relative positioning of Yutu lunar rover using VLBI phase-referencing mapping technology

作　　者：童锋贤 郑为民[1,2] 舒逢春[1,2] 

机构地区：[1]中国科学院上海天文台,上海200030 [2]中国科学院射电天文重点实验室,南京210008 [3]中国科学院大学,北京100049

出　　处：《科学通报》2014年第34期3362-3369,共8页Chinese Science Bulletin

基　　金：国家自然科学基金(11173052;11373061);国家高技术研究发展计划(2012AA121603);上海市优秀学术带头人项目(14XD1404300);上海市导航定位重点实验室项目(06DZ22101)资助

摘　　要：实时高精度VLBI技术在嫦娥三号任务中的成功应用,为探测器的成功落月及月面定位提供了重要保障.目前使用VLBI群时延及测距数据获得的玉兔巡视器在月面上相对着陆器的位置精度约100 m.为获得更精确的巡视器位置,在中国VLBI网同波束观测条件下,将天文相位参考成像方法成功用于月面定位.先将探月VLBI软件相关处理机结果转为通用FITS-IDI数据格式,然后用天文成像软件对着陆器和巡视器进行相位参考成像,得到巡视器天线相对于着陆器天线的角位置.在此基础上,提出了新的探测器月面相对定位算法,获得了玉兔相对于着陆器高精度月面位置.由于利用了同一基带转换器数据进行相位参考成像,消除了共同的系统误差,因此获得了极高的定位精度.本文分别完成了玉兔离开着陆器前,两器处于初始零位条件时,以及两器在不同位置相互拍照时的相对位置测量.理论分析、零位测量及与视觉定位结果的比较表明,采用VLBI相位参考法获得的玉兔巡视器的相对位置精度约为1 m.本方法可用于未来月球及行星表面巡视器相对位置精密测量、导航与视觉定位结果的标定.Real-time high-accuracy VLBI techniques played an important role in the Chinese lunar exploration mission in executing the soft landing of the Chang’E-3 probe on the lunar surface. To make this possible, in-beam phase referencing was used to obtain accurate relative positioning between the Yutu rover and the lander. The visibilities outputted by the correlator software were initially converted to the uniform FITS-IDI format. Astronomical mapping software, such as AIPS and Difmap, was then used to complete the mapping and angular positioning of the Yutu antenna. A new positioning algorithm was developed to determine the three dimension positions of the rover on the lunar surface. We took advantage of the in-beam observations, for which the signals from lander and rover were received in the same digital terminal, to eliminate system errors. Theoretical analysis, null position testing, and comparisons with visual localization results show that an accuracy of about one meter is achieved in relative positioning. The in-beam phase-referencing technique has potential for use in accurate positioning, navigation, and visual location calibration in future lunar and/or planetary exploration.

关 键 词：月面定位 相位参考定位 VLBI FITS-IDI 玉兔月球车 

分 类 号：V476.3[航空宇航科学与技术—飞行器设计] P184.5[天文地球—天文学]