Abstract
VLBI is at present the most accurate technique for measuring radiosource positions and the only method capable of high precision for a reasonable number of sources. The applications of VLBI astrometry in stellar, Galactic and extra-Galactic regimes are reviewed. In particular, substantial progress has been made in the last few years towards a global reference frame of extragalactic radiosource positions. The status of this frame, and of the link to the optical reference frames is also described.
Publisher
Cambridge University Press (CUP)