  Starting in 2013, Gaia will deliver highly accurate astrometric data, which
eventually will supersede most other stellar catalogues in accuracy and
completeness. It is, however, lim- ited to observations from magnitude 6 to 20
and will therefore not include the brightest stars. Nano-JASMINE, an ultrasmall
Japanese astrometry satellite, will observe these bright stars, but with much
lower accuracy. Hence, the Hipparcos catalogue from 1997 will likely remain the
main source of accurate distances to bright nearby stars. We are investigating
how this might be improved by optimally combining data from all three missions
in a joint astrometric solu- tion. This would take advantage of the unique
features of each mission: the historic bright-star measurements of Hipparcos,
the updated bright-star observations of Nano-JASMINE, and the very accurate
reference frame of Gaia. The long temporal baseline between the missions pro-
vides additional benefits for the determination of proper motions and binary
detection, which indirectly improve the parallax determination further. We
present a quantitative analysis of the expected gains based on simulated data
for all three missions.
