测地空间VLBI单源观测的奇异性问题  

SINGULARITY PROBLEM FROM GEODETIC SPACE VLBI OBSERVATIONS OF A SINGLE RADIO SOURCE

作　　者：舒逢春[1] 钱志瀚[2] 

机构地区：[1]中国科学院上海天文台,上海2000304 [2]中国科学院国家天文观测中心,北京100012

出　　处：《中国科学院上海天文台年刊》2001年第1期107-112,共6页Annals Shanghai Astronomical Observatory Chinese Academy of Sciences

基　　金：国家自然科学基金 (197730 2 0 )资助项目

摘　　要：介绍了测地空间VLBI论证实验 (GEDEX)的观测方案、预期目标和已获得的实测资料概况 ,并对测地空间VLBI单源观测导致的奇异性进行了理论分析和数值检验。对空间VLBI地—空基线时延的解析表达式分析表明 ,空间VLBI天文测地参数的联合平差要求每次实验至少观测 3颗射电源。基于对法矩阵的数值检验 ,GEDEX实验的单源观测资料可用于定轨和解算地球定向参数(EOP) ,但用于地面VLBI站坐标测定时 ,地面站坐标与钟参数强相关。为了克服单源观测导致的奇异性 ,我们提出在VSOP卫星的观测过程中 ,增加地面站对其它射电源的观测 ;或者在资料处理中 ,延长观测资料的时间跨度 。The description of space VLBI Geodesy Demonstration Experiment (GEDEX) is presented, and the singularity problem arisen from geodetic space VLBI observations of a single radio source is discussed. Theoretical analysis on the analytic expression of space VLBI ground-space baseline time delay shows that a minimum number of 3 radio sources is necessary for GEDEX parameters adjustment. Numerical investigations on normal matrix show that a single source observation data can be used to determine the orbit of VSOP satellite and EOP, but it is difficult to estimate the positions of ground VLBI stations due to their strong correlation with clock parameters. The ways to overcome singularity may be adding observations of more other sources from ground stations during the observations of a single radio source, or alternatively, extending space VLBI data spanning time to include more radio sources.

关 键 词：空间VLBI VSOP卫星 空间测地 论证实验 奇异性 

分 类 号：P22[天文地球—大地测量学与测量工程]