Spatial geodesy : resonances, mean elements and non gravitational forces

The space geodesy is one of the main application fields of celestial mechanics nowadays; in the launch of constellations of satellites (like Galileo) complicated structures of resonances appear, which, together with non gravitational forces, are at the origin of unsatble motions of the constellations. The treatment of the problem in mean elements (more adequate than the osculating elements) is one of the research axes of the team, and appears as a potential solution of this problem.