  The U.S. Naval Observatory Robotic Astrometric Telescope (URAT) is observing
the northern sky since April 2012 for an astrometric survey. Multiple overlaps
per year are performed in a single bandpass (680$-$750 nm) using the "redlens"
20 cm aperture astrograph and a mosaic of large CCDs. Besides the regular, deep
survey to magnitude 18.5, short exposures with an objective grating are taken
to access stars as bright as 3rd magnitude. A brief overview of the program,
observing and reductions is given. Positions on the 8 to 20 mas level are
obtained of 66,202 Hipparcos stars at current epochs. These are compared to the
Hipparcos Catalog to investigate its accuracy. About 20\% of the observed
Hipparcos stars are found to have inconsitent positions with the Hipparcos
Catalog prediction on the 3 sigma level or over (about 75 mas or more
discrepant position offsets). Some stars are now seen at an arcsec (or 25
sigma) off their Hipparcos Catalog predicted position.
