SC 1.3d: Africa

Chair: Elifuraha Saria (Tanzania)


Terms of Reference

Sub-commission 1.3d (Africa) is concerned with the definition and realization of a unified continental reference frame (AFREF) for Africa, which will be consistent and homogeneous with the global International Terrestrial Reference Frame (ITRF).



In collaboration with the IAG community and its services organisations and the National and Regional Mapping Organisations of Africa, the aims and objectives of Sub-commission 1.3d (Africa) are:

  • To define the continental reference system of Africa. The goal is to establish and maintain a unified geodetic reference network as the fundamental basis for the national 3-D reference networks fully consistent and homogeneous with the global reference frame of the ITRF;
  • To realize a unified vertical datum and support efforts to establish a precise African geoid, in concert with the African Geoid project (Project 2.3 in Commission 2) activities;
  • To establish continuous, permanent GNSS stations such that each nation or each user has free access to, and is at most 500km from, such stations;
  • To provide a sustainable development environment for technology transfer, so that these activities will enhance the national networks, and numerous applications, with readily available technology;
  • To understand the necessary geodetic requirements of participating national and international agencies and;
  • To assist in establishing in-country expertise for implementation, operations, processing and analyses of modern geodetic techniques, primarily GNSS.


Program of Activities

It is envisaged that the regionalization of AFREF will follow an approach that consists of three major phases:

  • The establishment of a framework of permanent or semi-permanent GPS base stations throughout the region that will become part of the worldwide IGS stations network;
  • The densification of the network of permanent or semi-permanent base stations, largely on a country-by-country basis, to determine the relationship between the national geodetic system and the ITRS, and to refine the transformation parameters necessary to relate the national systems to a common ITRF;
  • The third and equally important phase of the project will be to address the development of a more refined geoid model for Africa and the definition of a common vertical datum for the continent. This will be done in collaboration with the IAG Africa Geoid Project.

It is further planned to hold workshops and seminars to strengthen the science and knowledge of geodesy and GNSS within Africa and their application to the development of reference frames.