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Structure Corrections in Modeling VLBI Delays for RDV DataSince 1997, bimonthly S- and X-band observing sessions have been carried out employing the VLBA (Very Long Baseline Array) and as many as ten additional antennas. Maps of the extended structures have been generated for the 160 sources observed in ten of these experiments (approximately 200,000 observations) taking place during 1997 and 1998. This paper reports the results of the first massive application of such structure maps to correct the modeled VLBI (Very Long Baseline Interferometry) delay in astrometric data analysis. For high-accuracy celestial reference frame work, proper choice of a reference point within each extended source is crucial. Here the reference point is taken at the point of maximum emitted flux. Overall, the weighted delay residuals (approximately equal to 30 ps) are reduced by 8 ps in quadrature upon introducing source maps to model the structure delays of the sources. Residuals of some sources with extended or fast-varying structures improve by as much as 40 ps. Scatter of 'arc positions' about a time-linear model decreases substantially for most sources. Based on our results, it is also concluded that source structure is presently not the dominant error source in astrometric/geodetic VLBI.
Document ID
20020059986
Acquisition Source
Jet Propulsion Laboratory
Document Type
Conference Paper
Authors
Sovers, Ojars J.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA United States)
Charlot, Patrick
(Bordeaux 2 Univ. France)
Fey, Alan L.
(Naval Observatory United States)
Gordon, David
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Date Acquired
August 20, 2013
Publication Date
May 1, 2002
Publication Information
Publication: International VLBI Service for Geodesy and Astrometry: General Meeting Proceedings
Subject Category
Communications And Radar
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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