  Proper motions are computed and collected in a catalog using the Hipparcos
positions (epoch 1991.25) and URAT1 positions (epoch 2012.3 to 2014.6). The
goal is to obtain a significant improvement on the proper motion accuracy of
single stars in the northern hemisphere, and to identify new astrometric
binaries perturbed by orbital motion. For binaries and multiple systems, the
longer baseline of Tycho2 (~ 100 yr) makes it more reliable despite its larger
formal uncertainties. The resulting proper motions obtained for 67,340 stars
have a consequent gain in accuracy by a factor of ~ 3 compared to Hipparcos.
Comparison between UrHip and Hipparcos shows that they are reasonably close,
but also reveals stars with large discrepant proper motions, a fraction of
which are potential binary candidates.
