Pacome Delva: Relativity and positioning systems

Pacome Delva

European Space Agency

 

The classical concept of positioning system for a Global navigation satellite system (GNSS) would work ideally if all satellites and the receiver were at rest in an inertial reference frame. But at the level of precision needed by a GNSS, one has to consider curvature and relativistic inertial effects of spacetime, which are far from being negligible.

In this talk I will present two very different ways of including relativity in positioning systems: one way is to keep the newtonian conception of absolute time and space, and add a number of corrections depending on the desired accuracy; another way is to use a relativistic positioning system. This is a complete change of paradigm, as the constellation of satellites is described in a general relativistic framework.