17th IVS Directing Board meeting Summary notes Held at Fundamental Station Wettzell, Germany February 24, 2007 Notes by DB, first version 070324 revised 070331, 070410, 070425 Attending: Wolfgang Schlueter, Arthur Niell, Chopo Ma, Dirk Behrend, Ed Himwich, Kerry Kingham, Yasuhiro Koyama, Bill Petrachenko, Harald Schuh, Zinovy Malkin, Patrick Charlot, Alan Whitney, Xiuzhong Zhang, Hayo Hase, Roy Booth, Andrey Finkelstein, Shigeru Matsuzaka ACTIONS: 1. Welcome (Wolfgang Schlueter) Oleg Titov, Franco Mantovani, Yoshihiro Fukuzaki and Axel Nothnagel could not attend. Harald Schuh proposed that the ToR be changed to reflect the new structure of IAG. In section 5.4, the ex officio IAG Corresponding Members are to be changed from President of IAG Section II and President of IAG Section V to the following: "- President of IAG Commission 1 - Reference Frames - President of IAG Commission 3 - Geodynamics" The proposal was unanimously accepted by the board. 2. Results of the elections (Wolfgang Schlueter) The Coordinating Center updated the list of Associate Members prior to the elections. The elections of the representatives on the board were organized by the Election Committee consisting of Alan Whitney (Chair), Harald Schuh, and Dirk Behrend. The newly elected representatives are: Yoshihiro Fukuzaki (Networks Representative), Hayo Hase (Networks Representative), and Kerry Kingham (Correlators and Operation Centers Representative). The At Large elections were moderated by Wolfgang Schlueter. The board elected Xiuzhong Zhang, Oleg Titov, and Andrey Finkelstein as new at large members. 3. Reports and discussion 3.1 Chair's report (Wolfgang Schlueter) 3.1.1 Report about activities Activities since the last board meeting were reported. Correspondence: - Letter and copy of Proceedings volume to Prof. Lavanchy (Universidad de Concepcion) thanking for hosting the General Meeting in Concepcion, Chile. - Letter and certificate (plaque) of appreciation to Patrick Wallace (Rutherford Appleton Lab) thanking him for his service on the board as IAU representative. - Letter from Carey Noll (NASA GSFC) requesting a letter of support for CDDIS. [This letter was prepared and sent off the week after the meeting.] Wolfgang Schlueter participated in the October 7, 2006 GGOS Science and Steering Committee meetings. The online version of the article Wolfgang Schlueter and Dirk Behrend: "The International VLBI Service for Geodesy and Astrometry (IVS): Current Capabilities and Future Prospects" (DOI 10.1007/s00190-006-0131-z) was published; the article will be part of the upcoming Journal of Geodesy Special Issue "VLBI". 3.1.2 CRAF (Wolfgang Schlueter) Wolfgang Schlueter participated in a CRAF meeting and presented VLBI. The VLBI frequencies are not protected, which can cause severe problems, in particular on S-band. CRAF accepted IVS as a member of CRAF. The board agreed that Wolfgang Schlueter be the IVS representative to CRAF for a one-year period. Then, a new representative shall be chosen. 3.1.3 Cessation of VLBI operations in Canada Wolfgang Schlueter summarized the events and activities pertaining to the discontinuation of the Canadian VLBI operations. The activities of the Canadian Technology Development Center (TDC) and Bill Petrachenko's VLBI2010 Committee work can continue. 4. Election of the chair for the term 2007-2011 (Wolfgang Schlueter) The board unanimously elected Harald Schuh as new chair of the IVS for the term 2007-2011. Harald accepted the election. 5. Reports of the coordinators and WG chairs 5.1 Coordinating Center report (Dirk Behrend) Activities since the last board meeting were: - Publication of December Newsletter - Preparation of 2006 Annual Report - Maintenance of mailing lists and web site. - Coordination of IVS elections, including update of IVS Associate Member list. - Coordination of the fourth Technical Operations Workshop (TOW2007) - Liaison with other services in the frame of the INDIGO and GGOS projects. The Mailman mailing lists experienced a significant increase in junk mail. It is planned to roll out a scheme in which only submissions from the subscribers and members of a white list will be accepted; other submissions will be automatically discarded. The organization of the product area of the data centers is currently being overhauled. After restructuring, there will be an area for the current product solutions and another area containing all other product solutions (to document the history of solutions). Activities for the next several months include: - Publication of April and August Newsletters. - Publication of 2006 Annual Report. - Coordination of Technical Operations Workshop (TOW2007). - Coordination of the 5th IVS General Meeting (GM2008). - Upgrading the IVS web site to include station pages. - Continued participation in INDIGO and GGOS projects. 5.2 Observing Program Committee report (Dirk Behrend) Issues discussed in the period since the last board meeting were: - Mauna Kea VLBA proposal to investigate post-seismic deformation. - Polarization leakage proposal. - Harmonization of session start times. - Mark 5 Situation at Simeiz. - R&D 1 Gbps experiments. - Additional Monday e-Intensive. Yasuhiro Koyama provided a report on the SELENE activities. The launch of the satellites are planned for August 2007. Wettzell will contribute two weeks of observing time in 2008 to the SELENE mission. This will be coordinated between the IVS Coordinating Center and the SELENE mission team. 5.3 Analysis Coordinator report [Axel Nothnagel could not attend due to sickness.] Dirk Behrend mentioned that a Unified Analysis Workshop is planned shortly before the December 2007 AGU meeting in San Francisco. This workshop shall bring together analysts from GPS, VLBI, SLR, and DORIS. The details are still to be determined. 5.4 Network Coordinator report (Ed Himwich) Station status: - Canadian stations and correlator operations terminated - possible new stations in India - planned new stations in Korea - Fortaleza: operating with mixed bandwidth for R1 - Seshan: operating with only eight BBCs - Svetloe, Zelenchukskaya: continuing operations and improving - Badary: Mark 5B fringe test scheduled [test was successful] - Simeiz: got and lost a Mark 5A, now ordering Mark 5B and VSI4 sampler - RDV operations now Mark 5 A few IVS sites lack a co-located GPS system of the IGS. This year it is planned by NOAA/NGS to implement GPS at Hancock, NH and Kitt Peak, AZ. There will be no GPS installed at Los Alamos, NM (due to restricted access) and Owens Valley, CA (due to bad visibility). The IGS is working with IAA to implement GPS at Badary. Based on 145 sessions (out of 187 sessions), the 2006 data loss expressed in observing time amounted to 13.6%. This compares to 14.4% for 2005 and 12.5% for 2004. The CONT05 campaign had a data loss of only 4.0%. Clock offets: - station synchronization with UTC directly impacts UT1 offset and rate estimates - Bonn, Haystack, and WACO correlators have developed a unified approach in 2005: offset errors should be at 0.1 microsecond level, rate errors should be at 3E-13 seconds/second - VLBA correlator adopted Kokee VLBA formatter offset of zero (in agreement with IVS) - K5 (GSI) and S2 (Penticton) still need integration 5.5 Technology Coordinator report (Alan Whitney) VLBI2010 quick update and activities: - goal of 4 psec precision for group delay observable - investigations into new fast, affordable 12-m class antenna - antenna slew rates: ideally move between any two sky locations with about 30 seconds - broadband frequency range: ~2-15 GHz seems good choice - "burst mode" type of operation highly desirable (capture on-source data ~5-10 seconds into high-speed memory,then stream data to recording/transmission system while slewing) - development work on digital backends, flexible LO/IF, high-speed recording, e-VLBI - simulation studies on observing strategies and tradeoffs between antenna speed and solution precision Mark 5 status: - ~150 Mark 5A systems in operation at stations and correlators - Mark 5B is in regular use at Westford antenna; has been used in several experiments, including mm-VLBI - ~50 Mark 5B I/O upgrade kits have been built and distributed, but changeover from Mark 5A is slowed by VSI-E interface and correlator availability - Mark 5B is interfaced to Haystack Mark 4 correlator and in routine production use; MPI and USNO will support Mark 5B in near future - Mark 5A+ can be used to play back Mark 5B recordings (for correlators without Mark 5B direct interface) - Mark 5B+ (2 Gbps) is available as upgrade to Mark 5B - Successful 4 Gbps/station Mark 5B+ test experiment between Westford and GGAO in Jan 07 (using DBE0) - Plan 8 Gbps/station broadband test experiment using Mark 5B+ in March 07 - 4 Gbps Mark 5C under development; 10GigE interface - Other planned enhancements: SATA disk support early 2007; backwards compatible with old modules; standard Linux file access to Mark 5 data disks K5 developments: - successful 4 Gbps/station K5 experiment in Nov 2005, recorded on two K5 stations at each station - broadband sampler: 1 GHz bandwidth sampled at 2048 Msps - correlated with software correlator - Published: Publications of the Astronomical Society of the Pacific, 118: 1739-1748; 2006 December VSI status: - VSI-E: Beta version still being tested in transfers from Kashima to Haystack and Ny-Alesund to Haystack (still somewhat delayed by network availability at Haystack); expect positive result soon; awaiting successful demonstration before final ratification and submission to Internet Engineering Task Force (IETF) as international standard - VSI-H: has been highly successful; majority of world’s VLBI equipment expected to be VSI-H compatible by end 2007; needs extension to modern high-speed serial interface (10 Gigabit/sec Ethernet is likely choice) 5.6 VLBI2010 Committee report (Bill Petrachenko) Networks: For simulation studies networks of 16, 24, 32, and 40 stations have been selected. Simulations: Recent simulations make use of more realistic atmosphere models (moving turbulent screen). The simulation studies evaluate the required slew rates. Also scheduling issues are being looked at. Troposphere: It needs to be investigated on how information from numerical weather models and water vapor radiometers can be added best. Also the best way of parameterizing the troposphere is to be studied. Source structure: A prioritized list of sources is being compiled. The effects of structure corrections is being investigated. Antennas: There are new antenna proposals in Australia, New Zealand, Germany, and India. The feed needs to be tested and chosen. Other fields of investigation concern the antenna optics, the slew speed, and composite antennas. Prototyping: NASA/Haystack ran a successful high data rate S/X test. The ETS Lindgren feed was selected. A first broadband test is planned for early summer of 2007. 5.7 IERS/IVS Working Group for Second Realization of the ICRF (Chopo Ma) The WG will analyze relevant S/X astrometric and geodetic VLBI data sets. The goal is to present the second ICRF to relevant authoritative bodies and submit it to the IAU Division I working group on the second realization of the ICRF for adoption at the 2009 IAU General Assembly. The WG currently consists of 23 members from eight countries. Chopo Ma is Chair. The foreseen milestones are: - April 12, 2007: WG meeting in Vienna - Fall 2007: generation and comparison of time series - Spring 2008: analysis of time series - Mid 2008: defining source criteria - Fall 2008: selection of defining sources, analysis configuration - Spring 2009: generation of ICRF-2 catalogue, presentation to IVS, IERS, and IAU working group 6. Items related to IAG, IAU, FAGS, EVN 6.1 IAG 6.1.1 IAG (Harald Schuh) The IUGG General Assembly will take place in Perugia, Italy from 2-13 July 2007. Prior to the assembly, the IAG Council (delegates of member countries) will elect the members of the IAG Executive Committee. The next president of the IAG will probably be Michael Sideris (Univ Calgary). A new service was established: IAS (International Altimetry Service). All gravity services are under the umbrella of the IGFS (International Gravity Field Service). 6.1.2 Commission 1 (Chopo Ma) Nothing to report. Harald Schuh became the chair of sub-commission 1.4 on CRF to TRF relation. 6.1.3 IERS (Chopo Ma) ITRF2005: difference between IGN and DGFI in SLR scale and scale rate; continuing input of Technique Service SINEX files for monitoring; selection and review process for next ITRF. EOP C04 series: updating for consistency with ITRF2005. A joint analysis workshop is planned in conjunction with the 2007 FAll AGU meeting. 6.1.4 GGOS (Dirk Behrend and Chopo Ma) GGOS is working on its vision for the future geodetic observing system called GGOS2020. VLBI will be an integral part of this system. The GGOS2020 Reference Document (about 140 pages) is being drafted and is planned to be finalized by the IUGG General Assembly in Perugia, Italy in July 2007. This document is intended to provide background material and details for a global geodetic observing system in terms of concepts, conventions, infrastructure, and services. The main target group is the geodetic community proper. In addition to this document, a second document (the GGOS2020 Strategy) shall provide the main vision and an overview over the key issues. The scope of this strategy document will be about 30-40 pages with the target group being the decision makers and funding agencies. The GGOS Steering Committee will meet during the EGU in Vienna, Austria in April 2007 and again in Perugia, Italy in July 2007. Furthermore, a combined workshop of GGOS and IGOS-P (Integrated Global Observing Strategy Partnership) will take place in Frascati, Italy on November 5-6, 2007. 6.1.5 EVGA (Axel Nothnagel) [Axel could not attend due to sickness.] The next European VLBI meeting will be on April 12 and 13. 6.2 IAU (Patrick Charlot) For the time frame 2006-2009, the IAU established two Working Groups (WGs) with relevance for the IVS: - WG on the Second Realization of the ICRF: chaired by Chopo Ma, with 10 members, and with the goal to oversee the reali- zation of the second generation of the ICRF from VLBI obser- vations of extragalactic radio sources. - WG on Numerical Standard of Fundamental Astronomy: chaired by Brian Luzum, with 10 members, and with the goal to update the "IAU Current Best Estimates" conforming with IAU resolutions, the IERS Conventions, and the International Unit System (SI). Proceedings of the Journees 2005 (Warsaw) are available online at http://syrte.obspm.fr/journees2005. The Journees 2007 will take place at Paris Observatory (Meudon site) from 17-19 September 2007. The motto is "The Celestial Reference Frame for the Future". The second call for the Descartes-Nutation grants was made. Four projects were submitted and are under review by the Descartes-Nutation Advisory Board. 6.3 FAGS (Roy Booth) The next FAGS meeting will be at ICSU in Paris in early April 2007. 6.4 EVN (Patrick Charlot) A new proposal tool is available for proposal submission at http://proposal.jive.nl. It handles EVN proposals and EVN+VLBA proposals. Regular deadlines are the first of February, June, and October. Proposals are mostly astrophysical, but some astrometric proposals have also been accepted. 1 Gb/s observing shall be the default observing mode by the middle of 2007. An EVN2015 brainstorming meeting is planned for March 1-2 in Dwingeloo. The goal is to prepare the science case for the EVN2015 vision document and to define the role of the EVN in the SKA era. 7. Meetings 7.1 Meetings 2007 There are several VLBI meetings planned before the EGU General Assembly in Vienna. These are: - European VLBI Meeting, April 12-13 - 8th IVS Analysis Workshop, April 14 - 2nd VLBI2010 Working Meeting, April 15 The fourth Technical Operations Workshop (TOW2007) will be held at Haystack Observatory from April 30 to May 3. An e-VLBI workshop will be held in Bonn September 17-19. The 18th IVS Directing Board meeting will be held before the e-VLBI workshop in Bonn. It is planned for Saturday, September 15, 2007. 7.2 GM2008 (Dirk Behrend) The fifth IVS General Meeting will be held in St. Petersburg, Russia from March 3-6, 2008. A board meeting will be held in conjunction, probably after the GM on March 8, 2008. The Program Committee of the GM2008 shall consist of: Dirk Behrend (chair), Harald Schuh, Ed Himwich, Alan Whitney, Axel Nothnagel, Andrey Finkelstein, Zinovy Malkin, Oleg Titov, Bill Petrachenko, Jinling Li, Yasuhiro Koyama, and Patrick Charlot. The First Circular is planned to be sent out in March/April 2007. 8. Miscellaneous 8.1 Journal of Geodesy Special Issue "VLBI" (Harald Schuh) The special issue has 16 papers. It took about ten months from making the call to finishing the work. The printed version will be available in 4-6 months. 8.2 Meteorological Sensors (Harald Schuh) Several board members agreed to help in providing the height difference between the met sensor (pressure sensor) and the intersection of axes (reference point) for eight stations lacking this information.