Direct estimation of the Solar acceleration using geodetic/ astrometric VLBI observations

The secular aberration drift observed as the apparent proper motion of extragalactic radio sources is caused by the acceleration of the coordinate origin, the Solar System barycenter. So, the acceleration can be estimated as a global parameter by using the 30 years global geodetic/astrometric VLBI data. This estimation is independent of any kinematic or dynamic model of the Milky Way or statistics hypothesis. The estimated acceleration in the direction of the Galactic center is （0.80±0.04） cm· s^-1· yr^-1, while the other two components are （-0.01＋0.06） and （0.52±0.05） cm· s^-1· yr^-1 in the direction along the Solar motion in the Galactic plane and in the direction normal to the Galactic plane, respectively. The estimate of the acceleration independently provides another kinematics parameter without referring to any objects within the Galaxy.