4 juin - 7 juin 2013


S06 Astrom├ętrie de haute pr├ęcision et applications

Time Transfer functions as tool to validate light propagation solutions for space astrometry

Bertone S., Minazzoli O., Crosta M., Le Poncin-Lafitte C., Vecchiato A., Angonin M.C.

One of the main goals of modern astronomy is the realization of reference frames based on a large number of precise observations of celestial objects. This task requires highly technological capabilities but also an accurate theoretical description of light propagation taking into account General Relativity. At this regard, the standard procedure is to find a solution to null-geodesic equations. Another approach based on the Time Transfer Functions (TTF) has been developed, giving direct access to some important information without computing the whole trajectory of light. We will present here our last advances in extending the TTF formalism to a dynamical metric more adapted to describe the Solar System dynamics.

Also, the physical interpretation of high precision measurements is a delicate task ; we need reliable models where no previous well-attested experimental results is available. Concerning relativistic astrometry, nowadays two main models exist, GREM and RAMOD, both based on the geodesic approach. Here, we propose a method to cross-check their results with those of the TTF approach in a non-static case.