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In Brief

Projet AFREF ECA Geo-information Systems Section Dozie Ezigbalike ECA Geo-information Systems Section. In Brief. A scientific project using modern satellite based positioning to:

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In Brief

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  1. Projet AFREFECA Geo-information Systems SectionDozie EzigbalikeECA Geo-information Systems Section

  2. In Brief • A scientific project using modern satellite based positioning to: • Define a uniform geodetic reference frame Africa, which will form the basis of national three-dimensional reference frames consistent with the International Terrestrial Reference Frame (ITRF) • Establish a network of GNSS base stations for mapping and position determination all over Africa • Support scientific research in satellite

  3. Continental Coverage • Network of permanent GPS/GNSS base stations covering the whole continent • At least one in every country • Eventually, everywhere in Africa less than 1000 km from a base station

  4. African Ellipsoid • Data from the base stations will be used to compute the parameters defining the best-fitting mapping surface for the African continent

  5. Geodetic Reference • Uniform geodetic reference frame for Africa • Basis for national three-dimensional reference networks • Consistent with the International Terrestrial Reference Frame (ITRF) • Precise positioning requires real-time differential observations with two receivers • AFREF will provide network of base stations for practitioners

  6. Major Uses and Applications

  7. Regional Integration • Watersheds, river basins, ecosystems, wildlife are cross-border features • Regional infrastructure: roads, rail lines, water ways, … • Projects usually start at opposite ends • All require uniform mapping surface for regional analysis and planning

  8. Peace and Security • AU Border programme to delimit and demarcate all borders by 2012 requires neighbouring countries to agree on common borders • This requires the borders to be mapped on the same coordinate systems • That is, the same mapping surface • The same reference frame • Presently, every country has its own reference frame and associated coordinate systems • Country borders drawn on these national coordinate systems are not always consistent • Uniform coordinate system of AFREF will result in consistent representation of borders by neighbours • Reducing disagreements and conflicts

  9. Global Conformity • AU vision for Africa … “which asserts itself as a vibrant and dynamic force in the global arena” • Not yet in geodesy • AFREF will result in better fit of Africa to rest of the world

  10. International Mapping Standard • Current positioning technology based on satellite systems (GNSS) • Positions are defined in the World Geodetic System (WGS) • International Civil Aviation Organization (ICAO) adopted World Geodetic System (WGS84) for consistent mapping of Reference Points (ARP) • African countries are complying using satellite positioning technology • Need to have other geoinformation products (topography, cadastre, etc) in similar satellite-based coordinate systems

  11. Other Uses • Disaster mitigation • Search and rescue • Vehicle tracking and fleet management • Agriculture Monitoring • Crop Area mapping • … • …

  12. Atmospheric Research • Climate & Weather • Estimation of precipitable water vapour from network of GNSS stations in South Africa

  13. Month Month Dec Dec Nov Nov Oct Oct Sep Sep Aug Aug Jul Jul Jun Jun May May Apr Apr Mar Mar Feb Feb Jan Jan 0 2 4 6 8 10 12 14 16 18 20 22 24 0 2 4 6 8 10 12 14 16 18 20 22 24 Hour of day [UT] Hour of day [UT] Atmospheric Research 2 • Atmospheric research • Space weather • Ionospheric mapping of variation of annual TEC over South Africa from network of GNSS base stations 2004 2002 Thanks to B Opperman of Hermanus Magnetic Observatory for plots

  14. Geophysics Research • Plate motions • Plate motion estimates in South Africa from network of GNSS base stations C.J.H. Hartnady, E. Calais & R. Wonnacott (2007): “ITRF2000 velocity field from the South African TrigNet GPS array and the African GNSS network: Implications for Nubia-(Rovuma-Lwandle-)Somalia plate motions” East African Rift Conference, Kampala

  15. Objectives and Expected Outputs

  16. Formal Objectives 1 • To determine a continental reference system for Africa consistent and homogeneous with the global reference frame of the ITRF as a basis for national three-dimensional reference networks. • To realize a unified vertical datum and to support efforts to establish a precise African geoid. • To establish continuous, permanent GNSS base stations at a spacing such that the users will be within 1000km of a base station and that data is freely available to all nations.

  17. Formal Objectives 2 • To determine the relationship between the existing national reference frames and the ITRF to preserve legacy information based on existing frames • To provide a sustainable development environment for technology transfer so that these activities will enhance the national networks and other applications • Assist in establishing in-country expertise for implementation, operation, processing and analysis of modern geodetic techniques, primarily GNSS.

  18. Institutional Acceptance 1 • Un Economic Commission for Africa • CODI (now CODIST) an inter-governmental body of ECA • Have adopted the importance of AFREF and the Windhoek Declaration • Created a Working Group to deal specifically with AFREF • AFREF field project in work programme of ECA • UN Office for Outer Space Affairs (UNOOSA) • Have recognized importance of AFREF for variety of applications • Supported the Cape Town workshop and funded travel of participants to several AFREF-related events • International Association of Geodesy (IAG ) • Have recognized importance of AFREF and have committed support • Have created structures to co-ordinate project and provide technical assistance expertise • Supported the Cape Town workshop

  19. AFREF Structure (1) • To be designed, managed and executed from within African • Regional organization into: • NAFREF, WAFREF, CAFREF, EAFRAF, SAFREF • To be executed at the national level by national organizations responsible for geodetic matters • Technical expertise and support from the international geodetic community such as IAG, IGS etc.

  20. AFREF Structure (2) AMCOST Bureau Steering Committee AFREF Joint Secretariat Scientific Advisory Working Group Technical Advisory Working Group AU/HRST ECA/ISTD Sub Reg Data Processing SRDP SRDP SRDP SRDP NAFREF WAFREF CAFREF SAFREF EAFREF

  21. Planned Activities 2008-09 • May – June 08: Develop draft open data access policy and draft participation charter • June 08: Meeting of Current AFREF Steering Committee during Africa Array meeting in Johannesburg • June – Nov 08: Installation of five reference stations donated by Trimble • July 08: collect data on ongoing GPS/GNSS projects and initiatives in Africa • Aug 08: Training session at RCMRD • Mar 09: CODIST Meeting

  22. AFREF : Operationalization 1 • The strategy leads with building a Partnership with Providers. • Contacts with Trimble • Donation of the five GPS reference stations equipment that will add to the network of stations, for the determination of the African reference frame as well as being part of network of continuously observing reference stations (CORS). • In addition, the Commission has developed a proposal to densify the network such that positioning professionals (surveyors, engineers, environmentalists, mineral prospectors, etc) would always have access to parameters of at least one reference point within 500Km from any place in Africa

  23. AFREF : Operationalization 2 • The strategy leads with organizing an African Policy Makers’ Workshops. • To channel the Project into the NEPAD’s Programme on Science and Technology • To set up the activities into the umbrella of the ministerial structures of the African Union, notably the African Ministerial Council on Science and Technology (AMCOST).

  24. AFREF : Funding

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