Introduction and Background

The African Geodetic Reference Frame (AFREF) was conceived as a unified geodetic reference frame for Africa to be the fundamental basis for the national and regional three-dimensional reference networks fully consistent and homogeneous with the International Terrestrial Reference Frame (ITRF).  ITRF is the global reference frame system for the earth as adopted by the International Association of Geodesy (IAG). When fully implemented, it will consist of a network of continuous permanent GPS stations such that a user anywhere in Africa would have free access to GPS data and products and would be at most 1000 km from such stations.   Its full implementation will include a unified vertical datum and support for efforts to establish a precise African geoid.