HR: 08:00h
AN: G21B-01 INVITED     [Abstracts]
TI: Coordinate Time Series Generation
AU: * Herring, T A
EM: tah@mit.edu
AF: MIT, Room 54-618, 77 Massachusetts Av, Cambridge, MA 02139 United States
AB: Analyses of global positioning system (GPS) and other spaced based geodetic data generate results which have rank deficiencies and poorly resolved components that need to be resolved through the realization of a reference frame. A true rank deficiency exists for very long baseline interferometry (VLBI) measurements to extragalatic radio sources because these measurements are effectively insensitive to translation of the terrestrial coordinate system. Systems that use earth orbiting satellites have sensitivity to the center of mass of the Earth but the stability of this origin can be compromised by mismodeled orbital dynamics. Rotational rank deficiencies are common to all space based geodetic systems primarily because the transformation between terrestrial and celestrial frames is through the rotation axis of the Earth which moves by many meters with respect to the body of the Earth. Scale might not be considered a rank deficiency in most systems, but uncertain knowledge of the antenna characteristics on systems such as GPS can lead to scale uncertainties. In this paper, we examine methods for reference frame realizations on spatial scales of kilometers to global. The method we use is based on Bayesean estimation with conditions applied through the covariance matrix of estimated positions. Examples will be shown for times series generated on different temporal and spatial scales with emphasis on potential systematic differences in the time series that can develop with various frame realization assumptions.
DE: 1206 Crustal movements--interplate (8155)
DE: 1208 Crustal movements--intraplate (8110)
DE: 1243 Space geodetic surveys
DE: 1247 Terrestrial reference systems
DE: 1294 Instruments and techniques
SC: Geodesy [G]
MN: 2004 AGU Fall Meeting