Monday 22 August 2005

G4
1530-1700 hours

090
Earth kinematics and reference frame from combination of geodetic techniques
Biancale, Richard¹, Gambis, Daniel, Lemoine, Jean-Michel¹, Marty, Jean-Charles¹, Loyer, Sylvain³, Soudarin, Laurent⁴, Carlucci, Teddy⁵, Capitaine, Nicole⁵, Berio, Philippe⁶, Coulot, D⁶
1 CNES, Toulouse, France
2 IERS, Paris, France
3 NOVELTIS, Ramonville St Agne, France
4 CLS, Ramonville St Agne, France
5 Observatoire De Paris, Paris, France
6 Gemini, Grasse, France
Author email: Richard.Biancale@cnes.fr
In the framework of activities of the IERS Combination Research Centres, the GRGS (Groupe de Recherches de Geodesie Spatiale) studies the benefit of combining five space geodetic techniques (SLR, LLR, VLBI, GPS and DORIS) at the observation level in order to obtain a global and consistent solution for Earth Orientation Parameters (EOPs) : universal time UT1 and polar motion at 6-hour intervals, nutation corrections, as well as weekly station coordinates. Routine processing has started at the beginning of 2005 with a unique software package: the GINS software which computes normal equations from the five techniques on a weekly basis at the following different centres: CNES/OCA/Noveltis/CLS; the weekly combination is then performed with the DYNAMO software at Paris Observatory and made available to IERS in SINEX files in the framework of the Combination Pilot Project. Consistency and coherence in the treatment of the different techniques allow us to get homogeneous solution. Results in EOPs, nutation corrections and station coordinates are globally consistent at one centimetre level. Results are obtained without any constraint by using optimal relative weights for each technique according to the Helmert's optimal variance component estimation, by introducing ties between stations and by considering separately systematic behaviour for the various techniques.

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