Source Structure and Measurement Noise Are as Important as All Other Residual Sources in Geodetic VLBI Combined

doi:10.1029/2018JB015550

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	Source Structure and Measurement Noise Are as Important as All Other Residual Sources in Geodetic VLBI Combined
	Anderson, James M.1; Xu, Ming H.1,2
刊名	JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
	2018-11-01
卷号	123 期号:11 页码:10162-10190
关键词	VLBI IVS CONT14 source structure geodesy
ISSN号	2169-9313
DOI	10.1029/2018JB015550
英文摘要	The celestial sources observed by geodetic very-long-baseline interferometry (VLBI), most of which are quasars, are resolvedthey have a finite angular size as measured by the interferometeryet modern geodetic VLBI analysis techniques still treat these sources as if they are point-like. The errors introduced by source structure, the angular distribution of emission, have traditionally been believed to be a small fraction of the total measurement error budget. We analyzed the VLBI data of the CONT14 continuous observing campaign using standard geodetic and imaging techniques, along with an analysis of closures, combinations of interferometric measurements where the error contributions from station-based effects such as tropospheric and ionospheric errors, clock and cable length errors, station position errors, and so on, cancel exactly, leaving only nonclosing errors, principally source structure and measurement noise. Our statistical analysis of the closure information, based on actual VLBI observations revealed that nearly half (40%) of the total geodetic VLBI error budget (in terms of variance) in CONT14 came from source-structure effects, nearly the same variance as all station-based error sources (43%). The remaining error due to other nonsource-structure, nonclosing errors is also significant (17%). Previous studies, which were primarily simulation-based, did not account for the full range of effects of source structure on real measurements. Source structure is a major contributor to errors in geodetic VLBI, and source structure must be taken into account in the entire VLBI operational chain, from scheduling to analysis, in order to mitigate its effects on astrometric and geodetic measurements.
资助项目	project Ties between kinematic and dynamic reference frames (D-VLBI) as part of the DFG Research Unit Space-Time Reference Systems for Monitoring Global Change and for Precise Navigation in Space - German Research Foundation[SCHU 1103/4-1] ; project Ties between kinematic and dynamic reference frames (D-VLBI) as part of the DFG Research Unit Space-Time Reference Systems for Monitoring Global Change and for Precise Navigation in Space - German Research Foundation[FOR 1503] ; National Natural Science Foundation of China[Y646041001]
WOS研究方向	Geochemistry & Geophysics
语种	英语
出版者	AMER GEOPHYSICAL UNION
WOS记录号	WOS:000454775200009
内容类型	期刊论文
源URL	[http://119.78.226.72/handle/331011/32013]
专题	中国科学院上海天文台
通讯作者	Anderson, James M.; Xu, Ming H.
作者单位	1.GFZ German Res Ctr Geosci, Helmholtz Ctr Potsdam, Potsdam, Germany 2.Chinese Acad Sci, Shanghai Astron Observ, Shanghai, Peoples R China
推荐引用方式 GB/T 7714	Anderson, James M.,Xu, Ming H.. Source Structure and Measurement Noise Are as Important as All Other Residual Sources in Geodetic VLBI Combined[J]. JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH,2018,123(11):10162-10190.
APA	Anderson, James M.,&Xu, Ming H..(2018).Source Structure and Measurement Noise Are as Important as All Other Residual Sources in Geodetic VLBI Combined.JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH,123(11),10162-10190.
MLA	Anderson, James M.,et al."Source Structure and Measurement Noise Are as Important as All Other Residual Sources in Geodetic VLBI Combined".JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH 123.11(2018):10162-10190.