  We perform a kinematic analysis of the Hipparcos and TRC proper motions of
stars by using a linear Ogorodnikov-Milne model. All of the distant (r more
than 0.2 kpc) stars of the Hipparcos catalog have been found to rotate around
the Galactic y axis with an angular velocity of -0.36 +/- 0.09 mas/year. One of
the causes of this rotation may be an uncertainty in the lunisolar precession
constant adopted when constructing the ICRS. In this case? the correction to
the IAU (1976) lunisolar precession constant in longitude is shown to be -3.26
+/- 0.10 mas/yr. Based on the TRC catalog, we have determined the main Oort
constants: A = 14.9 +/- 1.0 and B = -10.8 +/- 0.3 km/s/kpc. The component of
the model that describes the rotation of all TRC stars around the Galactic y
axis is nonzero for all magnitudes, My= -0.86 +/- 0.11 mas/yr.
