  A relativistic positioning system has been proposed by Bartolom\'e Coll in
2002. Since then, several group developed this topic with different approaches.
I will present a work done in collaboration with Ljubljana University and the
ESA Advanced Concepts Team. We developed a concept, Autonomous Basis of
Coordinates, in order to take advantage of the full autonomy of a satellite
constellation for navigation and positioning, by means of satellite
inter-links. I will present the advantages of this new paradigm and a number of
potential application for reference systems, geophysics and relativistic
gravitation.
