  This chapter summarizes radio astrometry in relation to current very long
baseline interferometry (VLBI) projects and describes its perspectives with the
SKA. The scientific goals of the astrometry with the SKA have been discussed in
the international and Japanese communities of researchers, whose major issues
are shown here. We have demonstrated some of the issues, such as censuses of
possible targets and the technical feasibility of astrometry in the SKA
frequency bands. The preliminary results of our case studies on SKA astrometry
are also presented. In addition, possible synergy and commensality of the SKA
astrometric projects with those in the optical and infrared astrometric
missions, especially JASMINE (Japan Astrometry Satellite Mission for INfrared
Exploration) are discussed.
