Geodetic Reference Frames

Geodetic Reference Frames

Geodetic reference frames are the basis for The programme of the Symposium was divided three-dimensional, time dependent positioning according to the Sub-commissions, Projects in all global, regional and national networks, in and Study Groups of Commission 1 into eight cadastre, engineering, precise navigation, geo- general themes: information systems, geodynamics, sea level studies, and other geosciences. They are 1. Combination of space techniques necessary to consistently estimate unknown 2. Global reference frames and Earth rotation parameters using geodetic observations, e. g. , 3. Regional reference frames station coordinates, Earth orientation and 4. Interaction of terrestrial and celestial frames rotation parameters. Commission 1 “Reference 5. Vertical reference frames Frames” of the International Association of 6. Ionosphere modelling and analysis Geodesy (IAG) was established within the new 7. Satellite altimetry structure of IAG in 2003 with the mission to 8. Use of GNSS for reference frames study the fundamental scientific problems for the establishment of reference frames. One day of the Symposium was dedicated to a The principal objective of the scientific work joint meeting with the International Congress of the Commission is basic research on: of Federación Internationale des Géomètres - Definition, establishment, maintenance, and (FIG) and the INTERGEO congress of the improvement of geodetic reference frames. German Association of Surveying, Geo- - Advanced development of terrestrial and information and Land Management. The space observation techniques for this contributions presented at this meeting are purpose. integrated into these proceedings.

Observing our Changing Earth

At the XXIV General Assembly of the International Union of Geodesy and Geophysics (IUGG), held July 2-13, 2007 in Perugia, Italy, the International As- ciation of Geodesy (IAG) also had its quadrennial General Assembly. The IAG - organized and contributed to several Union Symposia, as well as to Joint Symposia with other Associations. It also organized ve Symposia of its own, one dedicated to eachofitsfourCommissionsanda fthonededicatedtotheGlobalGeodeticObse- ing System (GGOS). This volume contains the proceedings of these ve Symposia, which are listed below: Symposium GS001: Reference Frames Convener: H. Drewes Co-convener: A. Dermanis Symposium GS002: Gravity Field Convener: C. Jekeli Co-conveners: U. Marti, S. Okubo, N. Sneeuw, I. Tziavos, G. Vergos, M. Vermeer, P. Visser Symposium GS003: Earth Rotation and Geodynamics Convener: V. Dehant Co-convener: Chengli Huang Symposium GS004: Positioning and Applications Convener: C. Rizos Co-convener: S. Verhagen Symposium GS005: The Global Geodetic Observing System (GGOS) Conveners: M. Rothacher Co-conveners: R. Neilan, H.-P. Plag The Symposia were organized based on the structure of the IAG (i. e., one per Commission) and covered the there pillars of geodesy, namely geometry, Earth ro- tion, and gravity eld, plus their applications. The inclusion of the Symposium on GGOS - which is no longer a project but a major component of the IAG - integrated all geodetic areas and highlighted the importance of multidisciplinarity in, and for, geodetic research.

Reference Coordinate Systems for Earth Dynamics