IVS Products for Precise Global Reference Frames
  VLBI plays a unique and fundamental role in the maintenance of global reference frames which are required for precise positioning in many research areas related e.g to the understanding and monitoring of global changes, to geodesy, to space missions etc. The International VLBI Service for Geodesy and Astrometry coordinates internationally the VLBI components and resources and is tasked by IAG and IAU for the provision of products describing the Celestial Reference Frame through positions of quasars and their changes with time and also for products describing the rotation of the Earth in space. This paper summarises today's status of the products, achieved over the last years by evolving the observing programs. It points out the activities to improve further on the product quality to meet future service requirements, which will come up with the need for highly precise global reference frames. 
W. Schluter (1), N. Vandenberg (2) ((1) Bundesamt fur Kartographie und   Geodaesie, Fundamentalstation Wettzell, Germany, (2...