During the last decade, the deployment of GPS over Africa and the Southern hemisphere allowed a great advance in Research in the countries where GPS receivers were installed. These research advances concern the Geodesy, ionospheric and atmospheric physics especially at low and equatorial latitudes, and Space weather effects on GPS system. The GNSS tools are cheap compared to satellite tools, and as a consequence permit the participation of all the countries to the research in various fields. The GNSS data are complementary of the satellite data. The GNSS tools became very useful for capacity building in research, especially in Space Weather. Another important point is that GNSS data are used for many applications useful for the development of a country (aviation, cadastre, agriculture, infrastructures of the country etc…). It is important that all the users of GNSS data be aware of the progress in research on GNSS data, in order to take into account the scientific results in the development of their applications. Now with GNSS (GPS GLONASS GALLILEO ....), we can multiply the number of GNSS receivers and develop more research and application studies. This presentation will be devoted to the success story of the use of GNSS for capacity building in Space Weather, in Africa and Southern hemisphere.