GPS, GALILEO and GLONASS satellite navigation systems & GPS modernization

Satellite navigation technology is rapidly evolving. The modernisations in GPS, full deployments of GLONASS and GALILEO after 2008 will facilitate the development of new applications, hence opening new markets. It is time to prepare for this new commodity: ubiquitous provision of reliable and accurate positioning and timing services has already started to transform our societies. This paper will give an overview of satellite navigation systems, GPS, GLONASS and GALILEO as well as GPS modernisation which has been carried out fur a few years.