Thursday 25 August 2005

G1
1530-1700 hours

421
The contribution of ILRS to the International Terrestrial Reference Frame
Pavlis, Erricos C¹, Appleby, Graham², Kelm, Rainer³, Noomen, Ron⁴, Sciarretta, Cecilia⁵, Shelus, Peter J⁶
1 JCET/UMBC - NASA Goddard, USA
2 NSG UK
3 DGFI, Germany
4 DEOS/DUT, The Netherlands
5 ASI, Italy
6 CSR/UT, USA
Author email: epavlis@jcet.umbc.edu
Satellite Laser Ranging (SLR) measurements to geodetic satellites (spherical, cannonball shape) provide unambiguous, straightforward, range observations from which the orbits of the satellites may be determined simultaneously with tracking station coordinates and velocities, Earth Orientation Parameters, gravitational harmonics, and a plethora of other parameters of geophysical interest. With these products SLR aids in the definition and monitoring of the origin and scale of the terrestrial reference frame. Present requirements require these quantities to be monitored at the level of a few millimetres over the data span used in the solution. SLR was the only technique used to realize the ITRF2000 origin (and drift); SLR and VLBI together realized the ITRF2000 scale and scale-rate. In these respects, the SLR role in maintenance of the ITRF is quite critical, and this role will continue as we look forward to the development of future issues of the ITRF in collaboration with the other geodetic services. In this paper we outline the quality of the official ILRS combination products of weekly station coordinates and daily EOPs that are now routinely available to the community within a few days of the observations being carried out. We also review progress with the ILRS contribution to the new IERS initiative towards a realisation of ITRF2004 (for the first time) on the basis of weekly contributions from each of the participating techniques.

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