HR: 08:30h
AN: G21A-03 INVITED     [PDF]
TI: Satellite Laser Ranging Observations of the TRF Origin
AU: * Pavlis, E C
EM: epavlis@JCET.umbc.edu
AF: JCET-UMBC and NASA Goddard, 1000 Hilltop Circle, Baltimore, MD 21250 United States
AB: The origin of the Terrestrial Reference System (TRS) is realized through the adopted coordinates of its defining set of positions and velocities at epoch, constituting the conventional Terrestrial Reference Frame (TRF). Since over two decades now, these coordinates are determined through space geodetic techniques, in terms of absolute or relative positions of the sites and their linear and episodic motions. The continuous redistribution of mass within the Earth system causes concomitant changes in the Stokes' coefficients describing the instantaneous terrestrial gravity field, including its longest wavelength components. Seasonal changes in these coefficients have been closely correlated with mass transfer in the atmosphere, hydrosphere and the oceans. The new gravity-mapping missions, CHAMP and GRACE, and to a lesser extent the future mission GOCE, address these temporal changes from the gravimetric point of view. For the very low degree and order terms, there is also a geometric effect that manifests itself in ways that affect the origin and orientation relationship between the instantaneous and the mean reference frame. Satellite Laser Ranging (SLR) data, especially that from LAGEOS 1 and 2, contributed the most accurate observations of this effect yet, demonstrating millimeter level accuracy for weekly averages. Other techniques, like GPS and DORIS, have also contributed and continue to improve their results with better modeling and more uniformly distributed (spatially and temporally) tracking data. We will present the results from the latest analysis of over a decade of LAGEOS 1 and 2 data, discuss their accuracy and compare them to results from other techniques. Finally, we will look into potential improvements in the future, which will likely lead us to even finer resolution and higher accuracy through the constructive combination of the individual time series.
DE: 1214 Geopotential theory and determination
DE: 1223 Ocean/Earth/atmosphere interactions (3339)
DE: 1229 Reference systems
DE: 1241 Satellite orbits
DE: 1247 Terrestrial reference systems
SC: Geodesy [G]
MN: 2003 Fall Meeting