The Global Geodetic Observing System

Global Geodetic Observing System

The Global Geodetic Observing System (GGOS) has been established by the Int- national Association of Geodesy (IAG) in order to integrate the three fundamental areas of geodesy, so as to monitor geodetic parameters and their temporal varia- ?9 tions, in a global reference frame with a target relative accuracy of 10 or b- ter. These areas, often called ‘pillars’, deal with the determination and evolution of (a) the Earth’s geometry (topography, bathymetry, ice surface, sea level), (b) the Earth’s rotation and orientation (polar motion, rotation rate, nutation, etc. ), and (c) the Earth’s gravity eld (gravity, geoid). Therefore, Earth Observation on a global scale is at the heart of GGOS’s activities, which contributes to Global Change - search through the monitoring, as well as the modeling, of dynamic Earth processes such as, for example, mass and angular momentum exchanges, mass transport and ocean circulation, and changes in sea, land and ice surfaces. To achieve such an - bitious goal, GGOS relies on an integrated network of current and future terrestrial, airborne and satellite systems and technologies. These include: various positioning, navigation, remote sensing and dedicated gravity and altimetry satellite missions; global ground networks of VLBI, SLR, DORIS, GNSS and absolute and relative gravity stations; and airborne gravity, mapping and remote sensing systems.

The Global Geodetic Observing System

Towards an Integrated Global Geodetic Observing System (IGGOS)

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.