1. 35th COSPAR Scientific Assembly, Paris, July 18-25, 20041 IVS Products for Precise Global Reference Frames Wolfgang Schlüter Bundesamt für Kartographie und Geodäsie Fundamentalstation Wettzell Nancy Vandenberg SNVI, Inc./ Goddard Space Flight Center IVS web page: http://ivscc.gsfc.nasa.gov

2. 35th COSPAR Scientific Assembly, Paris, July 18-25, 20042 I V S - International VLBI Service for Geodesy and Astrometry IVS is a service of n IAG - International Association of Geodesy n IAU - International Astronomical Union n FAGS - Federation of Astronomical and Geophysical Data Analysis Services Main tasks of the IVS n global coordination of VLBI components in order to guarantee the provision of the products for u Celestial Reference Frame (CRF) VLBI is fundamental and unique for CRF F IAU Resolution, August 2001 u Terrestrial Reference Frame (TRF) VLBI contributes strongly to TRF (scale) u Earth Orientation Parameter (EOP’s) VLBI provides complete set of EOP, uniquely DUT1 Basis for collaboration and contributions Call of Participation in 1998 Proposals for 73 permanent components, –from 37 Institutions in 17 countries, –~ 250 Associate Members

3. 35th COSPAR Scientific Assembly, Paris, July 18-25, 20043 Map of the IVS Components

4. 35th COSPAR Scientific Assembly, Paris, July 18-25, 20044 Step to meet Service Requirements n When IVS started the demand for continuity in maintaining the reference frames forced to employ the existing observing programs (NEOS, CORE,.... INT) n 2001 review of products and observing programs ==> Working Group 2  Basis for improving products and evolving observing programs to meet service requirements

5. 35th COSPAR Scientific Assembly, Paris, July 18-25, 20045 Review of Products (examples from Working Group 2 Report) Products Status2001Goals(2002-2005) n polar motionaccuracy x p ~100  as, y p ~200  asx p, y p : 50... 25  as latency 1-4 weeks... 4 months4 - 3 days...1day resolution 1 day1 day...1h... 10min freq. of sessions ~3 d/week.........7d/week n UT1accuracy 5... 20  s3.................. 2  s latency 1 week4 - 3 days.... 1day resolution 1 day1 day....... 10min n ,  accuracy 100... 400  as50...25  as latency 1-4 weeks... 4 months4 - 3days... 1 day resolution 1 day1 day freq. of sessions ~3 d/week.......... 7 d/week n TRF (x,x,z)accuracy 5-20 mm5.............. 2 mm............ n CRFaccuracy 0.25-3 mas0.25 mas (improved distribution) freq. of solution 1 y1 y latency 3-6 months3............. 1 month(s) n...........................

6. 35th COSPAR Scientific Assembly, Paris, July 18-25, 20046 Improvements within IVS Observing Program u Appropriate observing programs started 2002 for F Earth Orientation Parameters (EOP): IVS-R1... IVS-R4 …, IVS-INT1/2 <Two rapid turn-around sessions each week, <Comparable xp, yp results. <Additional sessions employing S2 and K4 techniques (IVS-E3, IVS-INT2) F Terrestrial Reference Frame (TRF): IVS-T2 <Monthly TRF sessions with 8 stations F Celestial Reference Frame (CRF): RDV and IVS-CRF <RDV: Bi-monthly RDV sessions using the VLBA and up to 10 geodetic stations, <USNO: Source structure, NASA: TRF, NRAO: high precise source positions <IVS CRF (8-10 per year): Astrometric observations for new sources F CONT, whenever required IVS-CONT02 <14-day continuous sessions to demonstrate the best results that VLBI can offer <in 2002: CONT-session, October 16-31, 2002 F Monthly R&D sessions: IVS-R&D <to investigate instrumental effects, research the network offset problem êGeodetic VLBI observations increased by êabout 30% in 2002 compared to 2001 êabout 15% in 2003 compared to 2002 êabout 15% in 2004 compared to 2003

7. 35th COSPAR Scientific Assembly, Paris, July 18-25, 20047 2004 Observing Plan Summary

8. 35th COSPAR Scientific Assembly, Paris, July 18-25, 20048 IVS sites and cooperating VLBI sites

9. 35th COSPAR Scientific Assembly, Paris, July 18-25, 20049 Products for CRF n Monitoring of Sources u Positions u Structure n ICRF-Extension 1 u Completed 1999 u Adding 59 Sources n ICRF-Extension 2 u Completed 2002 u Adding 50 Sources

10. 35th COSPAR Scientific Assembly, Paris, July 18-25, 200410 Improved delay from observation to product availability 2 time series per week IVS R1 (Bo, Ha, Wa) IVS R4 (Wash) Results available approximately after two weeks Potential for Improve- ments Acceleration of Transportation (e-VLBI) Correlator processing (employing MK5)

11. 35th COSPAR Scientific Assembly, Paris, July 18-25, 200411 Combined EOP’s are regular IVS Products Analysis Coordinator: Axel Notnagel, Univ. Bonn n Complete set of EOP’s n Combined Solution from 5 (6) Analysis Centers n 20-30% improved u accuracy u robustness n R1 & R4 since 2002 Example : DUT1 form R1 and R4

12. 35th COSPAR Scientific Assembly, Paris, July 18-25, 200412 IVS Combined Product: Polar Motion X-Pol [µas]Y-Pol [µas] AC X-BiasWRMSY-BiasWRMS AUS-13,5196,01,1217,4 BKG-2,168,46,356,1 GSF2,052,1-1,944,2 IAA0,987,5-2,383,1 USN0,870,9-3,458,7

13. 35th COSPAR Scientific Assembly, Paris, July 18-25, 200413 IVS Combined Product: UT1-UTC UT1-UTC [µs] AC X-BiasWRMS AUSO,910,8 BKG0,32,8 GSF0,12,1 IAA-0,42,4 USN-0,22,4

14. 35th COSPAR Scientific Assembly, Paris, July 18-25, 200414 IVS Combined Product: d  and  d  dpsi [µas]deps [µas] AC X-BiasWRMSY-BiasWRMS AUS7,7188,1-18,989,4 BKG-23,9209,20,480,5 GSF-53,1196,4-10,176,6 IAA22,9140,814,659,7 USN-8,0219,76,882,2

15. 35th COSPAR Scientific Assembly, Paris, July 18-25, 200415 UT1-UTC from INTENSIVES with reference to CO4 MK4: Wettzell - Kokee Park (black) and K4: Wettzell – Tsukuba (red) With compliments from Dorothee Fischer, Univ.Bonn

16. 35th COSPAR Scientific Assembly, Paris, July 18-25, 200416 Tropospheric Parameter WZD as IVS product n Wet Zenith Delay u Regular for each R1 or R4 u Hourly resolution n Solution of 5 Analysis Centers n Combined by TU- Vienna n Combined IVS product officially accepted at the 9 th DB-meeting n 2-3mm precission comparable to GPS (or better?) With compliments from H.Schuh et.al., TU-Vienna

17. 35th COSPAR Scientific Assembly, Paris, July 18-25, 200417 Total Zenith Delay derived from CONT02 at Gilcreek With compliments from H.Schuh et.al., TU-Vienna

18. 35th COSPAR Scientific Assembly, Paris, July 18-25, 200418 Site namebias [mm] stddev [mm] Algopark7.1  4.8 Fortleza13.5  9.5 Gilcreek4.4  3.7 Hartrao5.0  8.1 Hobart263.2  7.4 Matera3.9  6.8 Medicina1.4  4.6 Nyales204.3  3.8 Seshan251.5  6.0 Wettzell2.5  4.3 Onsala604.8  4.5 mean:4.7  5.8 IGS - IVS difference in total zenith delays for all IVS-R1 and IVS-R4 sessions in 2002 after correcting for the station height difference Comparisons of Total Zenith delays: VLBI and GPS

19. 35th COSPAR Scientific Assembly, Paris, July 18-25, 200419 IVS Pilot Project: Time Series of Baseline Lengths

20. 35th COSPAR Scientific Assembly, Paris, July 18-25, 200420 Further improvements required n Overcome weekend gaps u automation for unattended observing needed n Reduce time delay and reduce expenses u employment of a modern disc based recording system (Mk5) u development of data transfer via the Internet (e-VLBI) u Employ VLBI Standard Interface n Increase robustness of the products, u more analysis centers with different software n Improve Network Configuration u Next VLBI generation (Vision 2010)

21. 35th COSPAR Scientific Assembly, Paris, July 18-25, 200421 Digital Recorders n Developments u Haystack- USA (Mk5) u CRL – Japan (K5) n Replacing MKIV by MK5 n Combination of various developments via u VSI (VLBI Standard Interface) n 2004: MK5a to MK5b u VSI included u Station Unit replacement at Correlator MK5A

22. 35th COSPAR Scientific Assembly, Paris, July 18-25, 200422 Mark 5 Usage Plan

23. 35th COSPAR Scientific Assembly, Paris, July 18-25, 200423 MPI-BKG Correlator Bonn

24. 35th COSPAR Scientific Assembly, Paris, July 18-25, 200424 Employing Internet for Datatransmission „E-VLBI“ Required time for the transfer (max. throughput 60%) Connection R1 R4 INT costs / a (WiN) F 64 kbit/s - - 100 d F 2 Mbit/s 93 d 69 d 3 d F 34 Mbit/s 6 d 4 d 5 h ~ 50.-k€ F 155 Mbit/s 1,2 d 1 d 1 h~180.-k€ F 622 Mbit/s 7 h 5 h 15 m~450.-k€ F 2,4 Gbit/s 1,9 h 1,3 h 4 m

25. 35th COSPAR Scientific Assembly, Paris, July 18-25, 200425 E-VLBI n Some demonstrations: u Keystone Project, 100km, CRL Japan F 256Mbit/s, permanent links F 1Gbit/s employing Internet Protocol u Mk 5 and K5 Tests: F 1 Gbit/s „near real time“ and „real time“ Demonstration between Westford MA - USA und GSFC MD - USA F 150Mbit/s experiment between Haystack/USA (MK5) and Kashima/Japan (CRL) (K5) several times 2002 and 2003 n Kashima sends data to Haystack n Intensiv next candidate for (near realtime ) e-VLBI n INT2 employing VSI

26. 35th COSPAR Scientific Assembly, Paris, July 18-25, 200426 Vision Paper 2010 focus on „next generation“ geodetic VLBI Working Group WG 3 established at the 10 DB-Meeting: u Needs for a vision paper: F Increasing requirements from IGGOS/IAG F RFI, frequency bands? F Aging antennas F Long term planning u Goals: F Unattended observing, more regular F Improved global coverage F Electronic data transfer F Near real time correlation and product provision F Report in July 2004 u Close collaboration with Radio-Astronomers (SKA)

27. 35th COSPAR Scientific Assembly, Paris, July 18-25, 200427 WG3: VISION 2010 nChaired by Alan Whitney and Arthur Niell nSubgroups uObserving Strategies (Bill Petrachenko) FFrequency Bands, RFI FFieldsystem and Scheduling FSource strength /structure /distribution FAntenna network configuration and observing strategies uRF/IF, Frequency and Time (Hayo Hase) FAntennas and Feeds FRF/IF and Calibration FTime and Frequency Standards uBackend Systems (Gino Tuccari) FBackends, digital filtering and BBC’s uData acquisition and transport (Alan Whitney) uCorrelation and fringe finding (Yasuhiro Koyama) uData analysis (Harald Schuh) uData archiving and management (Chopo Ma)

28. 35th COSPAR Scientific Assembly, Paris, July 18-25, 200428 Thank you !