  In its all-sky survey, Gaia will monitor astrometrically hundreds of
thousands of main-sequence stars within $\approx200$ pc, looking for the
presence of giant planetary companions within a few AUs from their host stars.
Indeed, Gaia observations will have great impact is the astrophysics of
planetary systems (e.g., Casertano et al. 2008), in particular when seen as a
complement to other techniques for planet detection and characterization (e.g.,
Sozzetti 2011). In this paper, I briefly address some of the relevant technical
issues associated with the precise and accurate determination of astrometric
orbits of planetary systems using Gaia data. I then highlight some of the
important synergies between Gaia high-precision astrometry and other ongoing
and planned, indirect and direct planet-finding and characterization programs,
both from the ground and in space, and over a broad range of wavelengths,
providing preliminary results related to one specific example of such
synergies.

Earth and Planetary Astrophysics