Hermann Drewes – författare

The book contains the papers presented at the IAG Symposium on Vertical Reference Systems held in Cartagena, Colombia, in February 2001. It covers the status report of existing height reference systems and the latest steps towards the establishment of a unified vertical reference system. Classical and modern height determination techniques are included as well as the determination of height reference surfaces like sea level and geoid. Emphasis is also given to the variations of the reference systems with time, i.e., sea level changes and geodynamic deformations.

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.

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.

The Symposium on Vertical Reference Systems (VeReS) was initiated on the occasion of the XXII General Assembly of the International Union of Geodesy and Geophysics (IUGG), Birmingham 1999, by Professor Dr. Wolfgang Torge, Past President of the International Association of Geodesy (lAG) and representative of lAG to the Pan-American Institute of Geography and History (PAIGH). The idea was to organise another joint symposium of lAG and PAIGH like the previous one held during the XX IUGG General Assembly at Vienna, Austria, in 1991. Good reasons for such a joint symposium were the great success and the ongoing activities of the Project on the South American Geocentric Reference System (Sistema de Referencia Geocentrico para America del Sur, SIRGAS) being sponsored by lAG and PAIGH since 1993. The SIR GAS Project (Working Group I) had presented a continental South American reference frame of 58 stations during the lAG Scientific Assembly at Rio de Janeiro, in 1997. This reference frame was already adopted by several South American countries as the basis for their new national horizontal geodetic datums (SIRGAS Working Group II). To overcome the problems of the heterogeneous vertical (height) datums between the individual countries, SIRGAS had installed its Working Group III "Vertical Datum" in 1997. As the discussion on the unification of vertical reference systems is also going on in lAG and other bodies of science and practice, it was decided to dedicate the symposium to this topic.

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.

The international symposium Towards an Integrated Global Geodetic Observing System was an initiative of section II Advanced Space Technology of the International Association of Geodesy (lAG). Ittook place in the building ofthe Bavarian Academy of Sciences in Munich from October 5 -9, 1998. About 130 scientists from 24 countries participated in the symposium. It was organized jointly by the Deutsches Geodatisches F orschungsinstitut and the Institut fUr Astronomische und Physikalische Geodasie/Technische Universitat MUnchen. The objective of the symposium was an analysis of the state-of-art of geodetic space techniques and an outlook into the possibility of the establishment of a global integrated observing system. In view of the fact that most geodetic space techniques have reached or approach the one part per billion relative precision level the question arises what their j oint and coordinated operation could offer to the study of system Earth. For this purpose the symposium was divided into four themes, i. e. reference system and datum integration, strength and weakness of space techniques, upcoming gravity field satellite missions, and implications for Earth sciences. Each of these themes was addressed by invited lectures of prominent scientists with sufficient time left for discussion. The oral sessions were complemented by poster sessions. A panel discussion at the closing session completed the program.

The international symposium Towards an Integrated Global Geodetic Observing System was an initiative of section II Advanced Space Technology of the International Association of Geodesy (lAG). Ittook place in the building ofthe Bavarian Academy of Sciences in Munich from October 5 -9, 1998. About 130 scientists from 24 countries participated in the symposium. It was organized jointly by the Deutsches Geodatisches F orschungsinstitut and the Institut fUr Astronomische und Physikalische Geodasie/Technische Universitat MUnchen. The objective of the symposium was an analysis of the state-of-art of geodetic space techniques and an outlook into the possibility of the establishment of a global integrated observing system. In view of the fact that most geodetic space techniques have reached or approach the one part per billion relative precision level the question arises what their j oint and coordinated operation could offer to the study of system Earth. For this purpose the symposium was divided into four themes, i. e. reference system and datum integration, strength and weakness of space techniques, upcoming gravity field satellite missions, and implications for Earth sciences. Each of these themes was addressed by invited lectures of prominent scientists with sufficient time left for discussion. The oral sessions were complemented by poster sessions. A panel discussion at the closing session completed the program.