用于地月空间VLBI的加权全频谱信号合成技术  

A weighted full-spectrum signal combining technology for cislunar Space-VLBI

作　　者：李志辉 张娟[1,5] 郑为民 童力[1,5] 刘磊 LI ZhiHui;ZHANG Juan;ZHENG WeiMin;TONG Li;LIU Lei(Shanghai Astronomical Observatory,Chinese Academy of Sciences,Shanghai 200030,China;University of Chinese Academy of Sciences,Beijing 100049,China;National Basic Public Science Data Center,Beijing 100190,China;Key Laboratory of Radio Astronomy,Chinese Academy of Sciences,Nanjing 210033,China;Shanghai Key Laboratory of Navigation and Positioning,Shanghai 200030,China)

机构地区：[1]中国科学院上海天文台,上海200030 [2]中国科学院大学,北京100049 [3]国家基础学科公共科学数据中心,北京100190 [4]中国科学院射电天文重点实验室,南京210033 [5]上海市空间导航与定位技术重点实验室,上海200030

出　　处：《中国科学：物理学、力学、天文学》2023年第5期124-134,共11页Scientia Sinica Physica,Mechanica & Astronomica

基　　金：国家自然科学基金(编号:11973011,11903067);上海市空间导航与定位技术重点实验室;中国科学院关键技术人才;上海市领军人才;上海天文台重点培育项目。

摘　　要：在我国探月工程四期嫦娥七号任务中,中继星将搭载一个4.2 m口径的X波段抛物面望远镜.该望远镜将与地基望远镜构成具有400000 km空地基线的月球轨道VLBI实验系统,实施地月空间VLBI实验.为尽可能提高空地VLBI基线灵敏度,提出了采用加权全频谱合成(FSC)技术增强地基信号.本文先理论推导了信号合成后的效果及两个望远镜信号合成时的最优加权系数比值.然后设计了VLBI加权全频谱合成算法,并基于实测信号利用网格搜索的方法找到最优加权系数,结果与理论推导相符.最后,利用“嫦娥四号”多组VLBI原始观测信号进行测试.结果表明,本文设计的信号合成算法可以大幅度提高VLBI基线射电源信号的信噪比.In the Chang’E-7 mission of the fourth stage of China’s Lunar Exploration Project,the relay satellite will carry a 4.1-maperture X-band parabolic telescope.This and the ground-based telescopes will form a lunar orbit very long baseline interferometry(VLBI)experimental system with the space-ground baseline up to 400000 km.To improve the sensitivity of this baseline,we propose a weighted full-spectrum signal combining method.First,we derive the optimal weighting coefficient ratio for combining the signals of the two telescopes.Then,we propose the VLBI weighted full-spectrum combining method whose optimal weight coefficient is determined by investigating the data,and the obtained result is consistent with the theoretical derivation.Finally,we use Chang’E-4 original VLBI observation data for method testing.The results show that the signal combining method proposed in this work can greatly improve the signal-to-noise ratio for VLBI observations.

关 键 词：地月空间VLBI 加权系数 全频谱合成(FSC) VLBI相关处理 基线信噪比 

分 类 号：V476.3[航空宇航科学与技术—飞行器设计] P228.6[天文地球—大地测量学与测量工程]