HR: 08:00h
AN: G41A-01    [Abstracts]
TI: Combination of Space Geodetic Techniques at the Measurement Level: Methodological Issues
AU: * Pollet, A
EM: arnaud.pollet@ign.fr
AF: IGN/LAREG, 6 et 8 avenue Blaise Pascal Cité Descartes MARNE-LA-VALLEE, Champs sur Marne, 77455, France
AU: Coulot, D
EM: david.coulot@ign.fr
AF: IGN/LAREG, 6 et 8 avenue Blaise Pascal Cité Descartes MARNE-LA-VALLEE, Champs sur Marne, 77455, France
AU: Capitaine, N
EM: Nicole.Capitaine@obspm.fr
AF: SYRTE, 61 avenue de l'observatoire, Paris, 75014, France
AU: Nahmani, S
EM: samuel.nahmani@ign.fr
AF: IGN/LAREG, 6 et 8 avenue Blaise Pascal Cité Descartes MARNE-LA-VALLEE, Champs sur Marne, 77455, France
AU: Altamimi, Z
EM: zuheir.altamimi@ign.fr
AF: IGN/LAREG, 6 et 8 avenue Blaise Pascal Cité Descartes MARNE-LA-VALLEE, Champs sur Marne, 77455, France
AB: Fundamental geodetic products such as the International Terrestrial Reference Frame (ITRF) and the Earth Orientation Parameters (EOPs) are currently computed by combinations of space-geodetic technique solutions. In the framework of the French Groupe de Recherche en Géodésie Spatiale (GRGS) activities, we directly combine the techniques (VLBI, SLR, GPS, DORIS) at observation level using the same models and software for all the individual data processing. The purpose is to better use all the information provided by the different techniques by reducing the number of steps of the combination processing to the minimum. In this work, we first study different ways to define the combined terrestrial reference frame. Indeed, each technique has its own sensitivity to the frame parameters and we must clearly define the multi-technique frame during the combination. Then, we reinforce this combination by using local ties between collocated instruments and common parameters for all techniques: EOPs and tropospheric delays. In order to use tropospheric delays as common parameters, we have extended the use of the ECMWF data (maps of wet and dry zenithal tropospheric delays for radiometric techniques) to the non-radiometric technique, such as SLR. Finally, we provide some prospects for data weighting and future improvements.
DE: 1225 Global change from geodesy (1222, 1622, 1630, 1641, 1645, 4556)
DE: 1229 Reference systems
DE: 1240 Satellite geodesy: results (6929, 7215, 7230, 7240)
DE: 1645 Solid Earth (1225)
SC: Geodesy [G]
MN: 2007 Fall Meeting