1. International Association of Geodesy Apr 17, 2007 1 GGOS2020 – Chapter 10 G. Beutler Astronomical Institute, University of Bern EGU Assembly Vienna April 17, 2007

2. International Association of Geodesy Apr 17, 2007 2 Contents 10.1 Basics 10.2 The GGOS High-level components 10.3 Building on the heritage 10.4 The GGOS environment 10.5 Organizational considerations

3. International Association of Geodesy Apr 17, 2007 3 10.1 Basics Purpose: The chapter is devoted to the implemen- tation of GGOS. Reminder: GGOS monitors and maintains the geometric and gravimetric reference frames and provides the transformation between the frames with state of the art observational tools.

4. International Association of Geodesy Apr 17, 2007 4 10.2 High-level components GGOS contains (blue: existing, red: new, magenta: in between/in development):  Terrestrial, technique-specific components  Uninterrupted series/sequence of space missions to maintain the reference frames  Entities combining the technique-specific products (not for gravity-related products)  Entity proposing geodesy-related space missions  Entity for communications and network coordination  Bureau of Standards  GGOS Coordination Office

5. International Association of Geodesy Apr 17, 2007 5 10.3 Building on the Heritage Level 1: Terrestrial infrastructure: Networks with  40 VLBI telescopes,  30 SLR/LLR observatories,  > 200 GNSS sites,  About 50 DORIS,  Absolute and super-conducting gravity sites IERS combining the technique-specific products Entity for communication and network coordination (including a network of fundamental stations) Bureau of Standards GGOS Coordination office

6. International Association of Geodesy Apr 17, 2007 6 10.3 Building on the Heritage Level 2: LEO missions (in particular CHAMP, GRACE, GOCE), IAS, IGFS, satellite mission entity Level 3: GNSS and SLR satellites (incl. Moon). „free“ geodetic infrastructure (SLR reflectors on all GNSS satellites). Level 4: Lunar and planetary „geodetic missions“: Establishment of planetary reference frame, planets‘ rotation, planets‘ gravity field, evolution of planets‘ satellites, planets‘ surface topography Level 5: Extragalactic objects (in particular Quasars) of geodetic interest to maintain celestial reference frame.

7. International Association of Geodesy Apr 17, 2007 7 10.4 GGOS Environment GGOS has to be viewed in the context of and put in relation with  GEO and ist GEOSS (IAG is a participating organiza-tion in GEO, acting through GGOS)  IGOS-P (Integrated Global Observing Stategy) under the auspices of UNESCO

8. International Association of Geodesy Apr 17, 2007 8 10.5 Organizational considerations IAG has a long tradition of establishing scientific services, starting with the ILS (International Latitude Service) in 1899, which was based on inter-governmental „contracts“. Starting in the 1980s IAG created the space-geodetic services based on voluntary, rather informal commitments of the participating organizations. GGOS is being deployed on this voluntary basis. At least the Coordination Office could/should/might be sponsored by an international political entity, e.g., the UN.  The GGOS2020 document is the basis for dealing with the sponsoring agencies and entities like GEO, UNESCO, etc.  As geodesy, in particular through GGOS, provides „in a certain sense“ the metrological basis for, research in and monitoring of Global Change, this „mission“ might be successful.

9. International Association of Geodesy Apr 17, 2007 9 10.5 Organizational considerations