International Association of Geodesy (IAG) |
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Associate Member since 2006 Official Website (external link): www.iag-aig.org
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| The International Association of Geodesy (IAG) is the scientific organisation responsible for the field of Geodesy. It has been a member association of the International Union of Geodesy & Geophysics (IUGG) since the inception of the IUGG in 1919. In 1862 the "Mitteleuropäische Gradmessung" - predecessor of the IAG - was established. The work of the IAG is performed within a component structure consisting of: commissions, inter-commission committees, services, the Communication & Outreach Branch, and the Global Geodetic Observing System (GGOS). The GNSS-related IAG service is the International GNSS Service (IGS), the reference frame IAG service is the International Earth Rotation & Reference System Service (IERS), and the time reference IAG service is the Time Department of the Bureau of Weights & Measures (BIPM). | ||
| The classical definition of Geodesy is the science concerned with the shape, size, and the gravity field of the Earth. Geodesy today is much more than that. It is a geoscience that nowadays deals with: | ||
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| Due to today's significantly improved geodetic instrumentation and techniques, Geodesy is more concerned with changes in the "geometry" and "gravimetry" than in the past, of features on, beneath or above the surface of the solid Earth and oceans. In the past, the main "customers" of Geodesy came from the surveying, mapping and geospatial disciplines, while today Geodesy serves all geosciences, including the geophysical, oceanographic, atmospheric, hydrological and environmental science communities. Geodetic "products" are not only contributing to our understanding of the Earth, they are also fundamental for many societal benefit areas, ranging from disaster prevention and mitigation, to the protection of the biosphere and the environment. Geodesy, in so many ways, contributes to increased security, to a better use of natural resources, and in general to satisfying the goal of sustainable development on our fragile planet. | ||
| Of particular note is that Geodesy serves society by providing reference frames for a wide range of practical applications, such as navigation on land, sea and in the air, and from construction of infrastructure to the determination of reliable boundaries of real estate properties and maritime zones. In the past these reference frames were created on a national or regional level. Today, through the exploitation of the existing and planned Global Navigation Satellite Systems such as GPS, GLONASS, Galileo, BeiDou, Geodesy provides access to point coordinates in a global reference frame anytime and anywhere on the Earth's surface with centimetre-level accuracy. |
| The IAG, through its services IGS, IERS and BIPM (Time Department) specifically dealing with geodetic and time reference frames, and precise positioning using GNSS, is an ICG Associate Member with a unique and highly valued set of expertise. The IAG is a co-chair of ICG Working Group D "Reference Frames, Timing and Applications", and has been working with its sister organisation the FIG, to promote the use of a single International Terrestrial Reference Frame (ITRF) for the precise alignment of individual GNSS datums, and to document these geodetic and time reference frames. In addition, the IAG and IGS are the precise GNSS positioning experts, responsible for the development of a range of GNSS techniques, data products and services to support the high precision GNSS user. In particular, the IGS has operated a globally distributed network of several hundred ground GNSS tracking stations since 1994. Initially the International GPS Service (as it was then known) generated a series of GPS data products (principally raw tracking data, and computed satellite orbit and satellite clock error states). Over a decade ago this was expanded to include GLONASS tracking and products, and most recently (since 2012) the IGS has been running a multi-GNSS test experiment known as M-GEX. The IAG and IGS are cooperating with Working Group A to define the scope and nature of an International GNSS Monitoring and Assessment (IGMA) activity. It is envisaged that the IAG/IGS would provide some components of a future IGMA service. |
| The ICG has considerable visibility within the IAG, with the IAG president (and in his place the vice-president) attending many of the annual ICG meetings. The primary focus is the ITRF and the contribution of the IGS to multi-constellation GNSS performance monitoring. |
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