One of the long-term objectives of the New Partnership for Africa’s Development (NEPAD) is "to eradicate poverty in Africa and to place African countries, both individually and collectively, on a path of sustainable growth and development and thus halt the marginalisation of Africa in the globalisation process". NEPAD was developed by African leaders and is based on national and regional priorities and development plans for the renewal of the continent. Effective planning and efficient implementation of regional development programmes requires maps and other geo-information. Because of the importance of geo-information, the NEPAD science and technology platform includes an objective to "promote cross-border co-operation and connectivity" and action to "establish regional co-operation on product standards development and dissemination, and on geographic information systems."

Geo-referencing Needs
The fundamental point of departure for any project, application, service or product reliant on some form of geo-referencing must be a uniform and reliable coordinate reference system. One does not build a house without a foundation or secure frame. Most countries have developed coordinate reference systems and frames which are used for national surveying, mapping, remote sensing, GIS and development programmes. Although these systems are in existence in many countries the state of repair and extent of their applications varies considerably. All the 53 countries in Africa are considered as developing nations, each with its own difficulties and challenges, and each has its own coordinate reference system and frame. Indeed, some countries have more than one system, each based on a different datum.
AFREF is therefore considered a unified frame for Africa. It will be the fundamental basis for the national 3D reference networks, fully consistent and homogeneous with the International Terrestrial Reference Frame (ITRF). When fully implemented it will consist of a network of continuous, permanent GPS stations such that a user anywhere in Africa will have free access to and will be at most 1,000km from such stations. Full implementation will include unified vertical datum and support for efforts to establish a precise African geoid, in concert with African Geoid project activities.

Previous Attempts
Perhaps the earliest attempt at unification was measurement of the Arc of the 30th meridian, initiated in 1879 by Sir David Gill and completed in 1954. This arc extended from a point near Port Elizabeth in South Africa to a point west of Alexandria in Egypt. As a result, a number of countries along the arc adopted the Clarke 1880 reference spheroid and the Cape Datum coordinate system as their national frame. However, there have been local adaptations of the system, which has resulted in slight differences between realisations from country to country of what is in name and basic definition the same system.

Lessons from ADOS
The next attempt came with the African Doppler Survey (ADOS) in the 1980s. ADOS used the US Navy Navigation Satellite System (US NNSS) as the primary observing tool. This system was commonly known as the Doppler positioning system, from the principle of transmitted frequency shift upon which it was based. The main objectives of the ADOS project were to provide:

• zero-order control for future geodetic networks for mapping control
  
• control for datum unification and strengthening
  
• an accurate geoid for Africa.

• The logistics of carrying out the observations simultaneously proved exceptionally difficult and limited the amount of suitable data.
  
• The rationale was not fully understood by participating countries, resulting in a lack of motivation and enthusiasm.
  
• The project was planned almost entirely by the IAG and the international community, with little input from African countries.

• the change in positioning technology by the introduction of GPS
  
• the concept of continuously operating GPS base stations
  
• the establishment of the International GPS Service (IGS) by IAG and its global network of GPS base stations.

• an IAG-created AFREF Sub-Commission through which scientific and technical support will be channelled; full commitment on the part of IGS to support the project
  
• an UNECA-created AFREF working group within its Committee for Development Information (CODI)
  
• recognition by United Nations Office for Outer Space Affairs (UNOOSA) (see websites and GIM International, February 2005, pp. 14-17) of the importance of the project; a recent report on the use of GNSS recommended the establishment of "a continental reference frame for Africa (AFREF), consistent with the International Terrestrial Reference Frame (ITRF)."

• Define the continental reference system of Africa. Establish and maintain a unified geodetic reference network as the fundamental basis for the national 3D reference networks, fully consistent and homogeneous with the global reference frame of the ITRF.
  
• Realise unified vertical datum and support efforts to establish a precise African geoid, in concert with IAG African Geoid project activities.
  
• Establish continuous, permanent GPS stations such that each nation or user has free access to and is at most 1,000km from such stations.
  
• Provide a sustainable development environment for technology transfer so that these activities will enhance the national networks and numerous applications with readily available technology.
  
• Understand the necessary geodetic requirements for participation in national and international agencies.
  
• Assist in establishing in-country expertise for implementation, operations, processing and analyses of modern geodetic techniques, primarily GPS.