IVS High Accuracy Products for the Maintenance of the Global Reference Frames as a Contribution to GGOS VLBI provides high accuracy and unique products for the realization and maintenance of the celestial and terrestrial reference frames, ICRF and ITRF, as well as for the Earth Orientation Parameters (EOP). In 2001 the products have been reviewed with respect to obtaining the highest accuracy and to improving the observing sessions in order to make best use of the resources which are made available by the IVS member institutions. Since 2002 improved observing sessions were coordinated by the IVS aiming at fast turn-around products for EOP and better products for TRF and CRF. The number of observations increased by more than 30% from 2002 to New products, e. g., the troposphere zenith path delay, are now being generated. Concerns about the aging technology, which has been used for the past three decades, and about radio interference problems that decrease the number of usable observations, led to the establishment of IVS Working Group 3. The working group was asked to examine current and future requirements for geodetic VLBI, including all components from antennas to analysis, and to make recommendations for a new generation of VLBI systems. The results are summarized in a vision paper, VLBI2010, which is required for coordination of new developments in VLBI and for plans to invest in new components by member institutions. This poster reviews IVS activities of recent years and gives an overview of new developments to meet future requirements prescribed by GGOS.  overcome the unbalanced network configuration,  increase the observing capabilities,  reduce technical failures of old components (antennas),  avoid the radio frequency interference,  obtain compatibility in technology, in particular in data recording,  develop dynamical scheduling to make best use of observation resources,  speed up the data transmission,  reduce the latency between observations and product provision,  reduce the systematic errors of the instrumentation,  reduce systematic errors caused by the analytical and numerical models,  increase the automation in the data handling process from the correlator to the final analysis,  support the combination with the other techniques. Summary International VLBI Service (IVS) Required Steps of Improvement IVS Products IVS is a service of:  IAG—International Association of Geodesy  IAU—International Astronomical Union  FAGS—Federation of Astronomical and Geophysical Data Analysis Services Main tasks of the IVS: global coordination of VLBI components in order to guaran- tee the provision of the products for:  Celestial Reference Frame (CRF)  Terrestrial Reference Frame (TRF)  Earth Orientation Parameters (EOP) Strength of VLBI: Very Long Baseline Interferometry (VLBI) plays a funda- mental role in the process of the realization and maintenance of the global reference frames and in the determination of the EOP:  VLBI allows the observation of quasars which realize the CRF;  VLBI can provide the complete set of EOP and is unique for the determination of DUT1;  VLBI provides most precisely the length of inter- continental baselines, which strongly support the realization and maintenance of TRF. Distribution of IVS components:  most components are located on the northern hemisphere,  distribution is not homogeneous,  there are clusters in Europe, North America, and Japan. Wolfgang Schlüter 1, Dirk Behrend 2, Ed Himwich 2, Axel Nothnagel 3, Arthur Niell 4, Alan Whitney 4 1 Bundesamt für Kartographie und Geodäsie, Fundamentalstation Wettzell, Germany 2 NVI Inc./NASA Goddard Space Flight Center, USA 3 Geodetic Institute of the University of Bonn, Germany 4 MIT Haystack Observatory, USA Take a look at the poster: VLBI2010: A Vision for the Future Geodetic VLBI CategoryProductsAccuracySolution Frequency Reso- lution Time- liness CRF  0.25 mas for as many sources yearly1 month  –time series 0.5 masmonthly1 month source structuremonthly1 month3 months flux density7 d/w1 hournear-real time TRFx,y,z–time series (one solution per session) 2…5 mm7 d/w1 hournear-real time episodic events2…5 mm7 d/w1 day annual solution coordinates velocities (multi session) 1…2 mm 0.1…0.3 mm/y yearly–1 month EOPDUT15 µs7 d/w continuous 10 minnear-real time d , d  25…50 µas7 d/w1 daynear-real time x p,y p 25…50 µas7 d/w10 minnear-real time dx p /dt, dy P /dt8…10 µas/day7 d/w10 min– Geodyna- mical Par- ameters solid Earth tides h, l0.1%1 y 1 month ocean loading A,  1%1 y 1 month atmosphere loading10%1 y 1 month Physical Parameters tropospheric par- ameters zenith delay gradients 1…2 mm 0.3…0.5 mm7 d/w 10 min 2 h near-real time ionospheric mapping0.5 TEC units7 d/w1 hnear-real time light deflection par- ameters 0.1%1 yall sessions 1 month ProductsGeneration ModeProduct Availa- bility Post-process- ing Overall Require- ments EOPcontinuous observations, time series with highest resolution close to real time for operational maintenance post-processing for obtaining best accuracy combination with other techniques TRFcontinuous observations for episodic events, time series for precise position monitoring close to real time for episodic events post-processing for obtaining best accuracy combination with other techniques CRFin combination with the other observing sess- ions for monitoring sources, campaign-wise post-processing Physical Parameter as by-product of EOP, TRF, and CRF campaigns near-real timepost-processingcombination with other techniques Space Vehicles on demandpost-processing IVS Components Future Demands on IVS Products Current status of geodetic VLBI coordinated by IVS:  30 Network Stations, acquiring VLBI data;  3 Operations Centers, coordinating the activities of a network of Network Stations;  6 Correlators, processing the acquired data;  6 Data Centers, distributing the products to users, providing storage and archiving functions;  21 Analysis Centers, analyzing the data, processing the results and products;  7 Technology Development Centers, developing new VLBI technology;  1 Coordinating Center, coordinating the daily and long term activities; In total, there are 74 Permanent Components, representing 37 institutions in 17 countries with ~250 Associate Members. IVS coordinates the activities of all VLBI components for geodetic and astrometric use based on the proposals made by the institutions in reply to a call for participation. In 2001 IVS Working Group 2 reviewed the IVS products and the corresponding observing programs. The following table gives an overview over the current products. The demands on a next generation VLBI system need to be based on the requirements imposed on the products IVS has to provide. With respect to accuracy and latency, the upcoming IAG project GGOS will drive future demands where the categories as given in the table will have different requirements and conditions in terms of operation and timeliness. Future demands on IVS products are placed by the require- ments set by  the users of highly precise global reference frames,  the scientific community. The IAG has established the project GGOS, which will result in the provision of a precise global reference system, con- sistent for decades. Several groups expressed their willingness on the international floor to contribute strongly to global and regional projects. Close to real time products, time series derived in post-processing mode to achieve highest quality, and products acquired from special observing campaigns are provided, as summarized in the following table. The first attempt to optimize the overall resources resulted from the WG2 report. Nevertheless, to meet the upcoming service requirements and to guarantee the products provision for the maintenance of global reference frames, much more effort is required. Urgent steps of improvement are: Location of stations:  some astronomical antennas also available occasionally for geodesy (e.g. Noto),  some built specifically for geodesy and located for geographic distribution (e.g. TIGO) or for convenience (e.g. Tsukuba),  southern hemisphere undersampled. Impact of GGOS accuracy demands (mm-accuracy in sta- tion position):  accuracy improvement of time delay (VLBI observable) from 30 ps to 4 ps required,  may require time and frequency stability improvement of one order of magnitude,  better ways of correcting for the clocks and atmosphere needed due to the correlation among station height, atmospheric refraction, and time scale. Other considerations:  variations in source positions and source strengths need long term, continuous monitoring,  source catalog needs to be extended for precise positions of the quasars beyond S- and X-band,  capacity to link dedicated satellites to the CRF by means of VLBI observations. Collage of VLBI antennas (clockwise from top left): Harte- beesthoek, GGAO, Ny Ålesund, O’Higgins, Kashima (11-m).