The establishment of the Global Geodetic Observing System (GGOS) has been only possible thanks to the strong international cooperation promoted and hosted by the International Association of Geodesy (IAG) for more than fifteen decades. The idea of GGOS was born in the end of the 1990s.
The first event, which may be understood as the birth date of GGOS, is the international symposium “Towards an Integrated Global Geodetic Observing System” held in Munich in October 1998 and organized by the former IAG Section II “Advanced Space Technology” and the former IAG Commission VIII “International Coordination of Space Techniques for Geodesy and Geodynamics” (CSTG).
At the IAG1999 General Assembly in Birmingham, jointly with the 22th General Assembly of the International Union of Geodesy and Geophysics (IUGG), an IAG Review Committee was created to propose a new IAG structure that is in agreement with the innovative geodetic techniques and methods becoming available at that time. Modern Geodesy should be viewed from the global perspective and efforts of all branches of this science should be bundled to serve the same goal. The IAG Review Committee organized a retreat in February 2000, where experts from Geodesy, Earth sciences, government organizations, etc. were invited to develop, together with the Committee, a first draft for the new structure. After a series of meetings and different drafts, the IAG Review Committee prepared a proposal of new IAG Statutes and Bylaws describing the new IAG structure and proposing to establish GGOS as IAG’s first association project. IAG projects are “of a broad scope and of highest interest and importance for the entire field of Geodesy. These projects serve as the flagships of the IAG for a long time period (decade or longer)”. An IAG project is nothing but the focal point of most, if not all, activities of the IAG. This makes evident that GGOS realizes a milestone in the advancement of Geodesy.
The proposal with the new IAG structure and GGOS as IAG project was approved by the IAG governing bodies (IAG Council and IAG Executive Committee) at the IAG2001 Scientific Assembly in Budapest. A GGOS Planning Committee was established in the same year and it developed a proposal including definition, vision and mission statements for GGOS, as well as its main objectives, the science rationale, and a first implementation plan.
This proposal was accepted by the IAG Executive Committee and the IAG Council at the IAG2003 General Assembly in Sapporo, which was held jointly with the 23th IUGG General Assembly. Indeed, GGOS was endorsed by the IUGG through Resolution No. 3 at the same General Assembly. The GGOS Planning Committee was replaced by a GGOS Implementation Committee at the IAG2005 Scientific Assembly in Cairns.
At the IAG2007 General Assembly, jointly with the 24th IUGG General Assembly, in Perugia, the IAG project GGOS became a formal component of IAG being at the same level of the Commissions and the Services in the IAG structure. Since that time, some updates to the organizational structure of GGOS were implemented in order to reflect recent developments and strategic direction.
After different calls for participation, the initial GGOS structural components were established: The GGOS Bureaus on ‘Networks and Communications’ and ‘Standards and Conventions’ started working in January 2009. They were renamed in 2014 to GGOS Bureaus for ‘Networks and Observations’ and ‘Products and Standards’, respectively.
In November 2009, an Intergovernmental Committee for GGOS (ICG) was created to address major issues (specially funding) related to the improvement of the global geodetic infrastructure.
In 2010, it became the GGOS Inter-Agency Committee (GIAC), which was supported by spatial and national geodetic agencies.
In 2014, they were renamed to Focus Areas.
In 2017, a new Focus Area dedicated to ‘Geodetic Space Weather Research’ was established
In November 2019 the Focus Area on Sea Level was discontinued.
With the release of the United Nations’ Resolution on the Global Geodetic Reference Frame (UN-GGRF) for Sustainable Development, adopted at the UN General Assembly on February 26, 2015 and the creation of the Sub-Committee on Geodesy of the UN Committee of Experts on Global Geospatial Information Management (UN-GGIM), the GIAC functions were transferred to the UN Subcommittee on Geodesy and GIAC was discontinued.
As a mechanism to increase participation in GGOS, especially in the under-represented areas of Africa, Asia-Pacific, and South and Central America, a new component of GGOS, known as GGOS Affiliates, was created in 2017. GGOS Japan, formerly known as the GGOS Working Group of Japan, became the first GGOS Affiliate in November 2017.
GGOS represents the IAG within the Group on Earth Observations (GEO), participates in the Committee on Earth Observation Satellites (CEOS), and has a stake in the United Nations Global Geospatial Information Management (UN-GGIM) Subcommittee on Geodesy. Given the fundamental importance of GGOS participation in these external organizations, the position of Manager of External Relations was created in January 2018.
The national geodetic commissions of Germany (DGK), Austria (ÖGK) and Switzerland (SGK), encompassing the D-A-CH region, joint their efforts in GGOS-related activities and in better exploiting the potential of GGOS in terms of science and infrastructure and established the second GGOS Affiliate called GGOS D-A-CH. Their application was approved by the GGOS Coordinating Board in May 2021.