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Mobile very long baseline interferometry and Global Positioning System measurement of vertical crustal motionMobile Very Long Base Interferometry (VLBI) and Global Positioning System (GPS) geodetic measurements have many error sources in common. Calibration of the effects of water vapor on signal transmission through the atmosphere, however, remains the primary limitation to the accuracy of vertical crustal motion measurements made by either technique. The two primary methods of water vapor calibration currently in use for mobile VLBI baseline measurements were evaluated: radiometric measurements of the sky brightness near the 22 GHz emission line of free water molecules and surface meteorological measurements used as input to an atmospheric model. Based upon a limited set of 9 baselines, it is shown that calibrating VLBI data with water vapor radiometer measurements provides a significantly better fit to the theoretical decay model than calibrating the same data with surface meteorological measurements. The effect of estimating a systematic error in the surface meteorological calibration is shown to improve the consistency of the vertical baseline components obtained by the two calibration methods. A detailed error model for the vertical baseline components obtained indicates current mobile VLBI technology should allow accuracies of order 3 cm with WVR calibration and 10 cm when surface meteorological calibration is used.
Document ID
19870034657
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Kroger, Peter M.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Davidson, John M.
(California Institute of Technology Jet Propulsion Laboratory, Pasadena, United States)
Gardner, Elaine C.
(Kalamazoo College MI, United States)
Date Acquired
August 13, 2013
Publication Date
August 10, 1986
Publication Information
Publication: Journal of Geophysical Research
Volume: 91
ISSN: 0148-0227
Subject Category
Geophysics
Accession Number
87A21931
Distribution Limits
Public
Copyright
Other

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