18th IVS Directing Board meeting Summary notes Held at University of Bonn, Bonn, Germany September 15, 2007 Notes by DB, first version 070924 revised 071019, 071029 Attending: Arthur Niell, Chopo Ma, Oleg Titov, Kerry Kingham, Bill Petrachenko, Harald Schuh, Patrick Charlot, Alan Whitney, Hayo Hase, Axel Nothnagel, Dirk Behrend Teleconferenced in for the duration of their actions: Ed Himwich (4.5), John Gipson (5.) ACTIONS: 1. Welcome (Harald Schuh) Yoshihiro Fukuzaki, Xiuzhong Zhang, Andrey Finkelstein, Ed Himwich, and Ray Norris could not attend. 2. Change of Board members, approval of minutes of 17th DB meeting (Dirk Behrend, Harald Schuh) Dirk Behrend introduced the new DB member Ray Norris who succeeded Roy Booth in the position as FAGS Representative. The minutes of the 17th DB meeting were approved. The agenda for the 18th DB meeting was approved without changes. 3. Reports including discussions (Harald Schuh) 3.1 Chair's report (Harald Schuh) 3.1.1 Activities since the last DB meeting Activities since the last board meeting were reported. Correspondence: - Letter of support to CDDIS. - Letter of support to Bordeaux Observatory. - Letter to GSI supporting the provision of additional resources for the Int3 Intensives. - Letter from the Minister of Natural Resources Canada to the IVS Chair thanking for the comments with respect to the cancellation of the Canadian VLBI program. Dirk Behrend, Wolfgang Schlueter, and Harald Schuh prepared the IVS contribution to the IAG Travaux 2007. The article is available in the Publications Section of the IAG Web site: http://www.iag-aig.org/attach/9316bd52b9894897de444a340660ae5f/ivs.pdf Harald Schuh and Dirk Behrend participated in the IUGG General Assembly in Perugia, Italy. Harald attended the GGOS Steering Committee meeting on July 9 in Perugia. The GGOS Unified Analysis Workshop will take place in Monterey, CA in December. This workshop is on invitation only; the IVS nominated Axel Nothnagel, Johannes Boehm, Dan MacMillan, Arthur Niell, and Volker Tesmer as the five IVS representatives. Harald Schuh visited the Korean VLBI groups (KASI, NGII, Ajou University) as well as all three KVN VLBI sites (Seoul, Ulsan, Jeju) in August 2007. Chopo Ma reported on two Korean visitors from NGII at Goddard. 3.1.2 Continuation of TROPO products of the IVS (Harald Schuh) There are two TROPO products: weekly and long-term solutions. The Institute of Geodesy and Geophysics (IGG) produces a combined solution out of the submitted individual solutions. In November 2006, the IGS (International GNSS Service) ceased to create a combined GPS solution. Losing a guaranteed bias-free comparison product data set, IGG stopped the rapid combination work for the IVS weekly solutions. Several users (e.g., EUREF) complained about the loss of the rapid IVS combination product, which they use for validity checks. IGG proposed to resume the rapid combination for IVS-internal session validity checks and to satisfy user demands, and to continue the long-term combination with an update interval of about 6 months. The board approved the proposal. 4. Reports of the Director, Coordinators, WG and Committee Chairs 4.1 IVS CC Director's report (Dirk Behrend) Activities since the last board meeting were: - Publication of April and August Newsletters - Publication of 2006 Annual Report - Maintenance of mailing lists and web site. - Coordination of the fourth Technical Operations Workshop (TOW2007) - Coordination of the fifth General Meeting (GM2008) - Liaison with other services in the frame of GGOS and FAGS The handling of the Mailman mailing lists was changed to allow submissions from subscribers and white list members only. Other submissions are automatically discarded. The roll-out went smoothly. The Coordinating Center organized the pre-print-run order of the Journal of Geodesy special issue 'VLBI' (Vol. 81, Nos 6-8, June 2007). The community ordered about 100 copies. Activities for the next several months include: - Publication of December 2007 and April 2008 Newsletters. - Coordination of the 5th IVS General Meeting (GM2008). - Upgrading the IVS web site to include station pages. - Continued participation in GGOS and FAGS activities. 4.2 OPC short report (Dirk Behrend) Issues discussed in the period since the last board meeting were: - CONT08: A continuous VLBI campaign is planned for 2008. The observation window was fixed to May-August 2008. The likely observing rate is 512 Mbps. - Status of R&D 1-Gbps EOP testing. - R&D slot(s) for VLBI2010 testing. - 2008 Planning. 2008 basically carries forward the 2007 plan. - Ultra-rapid e-VLBI session: The OPC endorsed a proposal of ultra- rapid e-Intensive sessions on two “parallel baselines” between Europe and Japan (On-Ts, Mh-Kb). - Naming of Intensive sessions. 4.3 Media Pool Evolution (Dirk Behrend) The current geodetic media pool can sustain the observing program for 2008: there are 453 modules required and 466 are available. The small margin does not allow to go to higher observing rates for any of the session types. For CONT08 about additional 90 D-size modules would need to be purchased. Dirk Behrend will draft a message for the stations that will encourage the purchase of disk modules in general. 4.4 Analysis Coordinator's extended report (Axel Nothnagel) Activities of the Analysis Coordinator's office (ACO) include: - Operation: ACO supports data handling and analysis of EOP combinations for the rapid series (IVS-R1 and IVS-R4) and for the quarterly series (all IVS sessions). ACO also produces the IVS "baseline lengths" product. - Research and Development: - SINEX files (datum-free normal equations) of Intensives. The IVS DCs accept Intensive SINEX files with the extension .sni. - TRF deficits: The Japanese sites (other than Tsukuba) should be included in continental-wide experiments to strengthen the VLBI TRF. - Deficits in CONT05: 30-min gaps between individual days result in peaks in the UT1-TAI time series. - Identification of network configuration in EOP files: EOP results may originate from different network configurations. For the EOP files (.eops, .eopi) an additional field was added. A new SINEX file is needed for each network configuration. - Meetings: - Organized the 8th IVS Analysis Workshop (Vienna, April 14, 2007). All IVS Analysis Centers now consistently use the pole tide correction of the IERS Conventions. - Started Coordinating the IVS contribution to the GGOS Unified Analysis Workshop in Monterey, CA (Dec 5-7, 2007) with proposals for common research projects. - Communications: - Letter to Andrey Finkelstein (IAA) requesting the release of the Russian data to IVS - Letter to Seiji Manabe (NAOJ) requesting the release of the Japanese data to IVS Bill Petrachenko commented that the VLBI2010 Committee has not looked into the automation of the analysis. Harald responded that the ACs should be encouraged to do research in analyzing data from the next generation system and possibly modernize their software. 4.5 Network Coordinator's short report (Ed Himwich via telecon) Station status: - Korea: NGII's antenna order delayed - Yebes: coming along. Dirk Behrend reported that first fringes are expected by the end of the year. - Australia: Auscope going to tender soon; Ceduna may have S/X soon from Univ Tasmania, but no back-end yet - Russian stations: - antenna reliability problems at Svetloe and Zelenchukskaya continue - Badary Mark 5B fringe test successful and now limited operation - Simeiz: ready for disk observing very soon, thanks to EVN remote PC and Mark 5A help - South American stations: shipping problems require longer, larger pipeline of disks - Fortaleza: cryogenics parts arrived, system mostly repaired, phase cal may be a problem - "Upper X band" problem: - Fortaleza, Matera, Zelenchukskaya, (Seshan), TIGO - cause unclear, may be more than one Clock offsets: - Station synchronization with UTC directly impacts UT1 offset and rate measurements - Bonn, Haystack, and WACO correlators developed a unified approach in 2005: - Offset errors should be at 0.1 microsecond level now (few microsecond level previously) - Rate errors should be at 3E-13 seconds/second - VLBA correlator - Now uses Kokee VLBA formatter offset of zero – in agreement with IVS - Must consider whether there are correlator-to-correlator offsets 4.6 Technology Coordinator's short report (Alan Whitney) Mark 5 status: - ~150 Mark 5A systems in operation at stations and correlators - Mark 5B is in regular use at Westford and Badary; soon to be in regular use at Parkes - ~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 installed and working at Haystack, USNO, and Bonn correlators - Mark 5B+ (2 Gbps) is available as upgrade to Mark 5B; ~15 Mark 5B+ systems in existence - Successful 4 Gbps/station Mark 5B+ test experiment between Westford and GGAO in Jan 07 (using DBE0); major mm-VLBI experiment in Apr 07 at 4 Gbps/station - 4 Gbps Mark 5C under development; 10GigE interface - Other planned enhancements: SATA disk support on Mark 5 available; backwards compatible with old modules; standard Linux file access to Mark 5 data disks under developement VSI status: - VSI-E: Beta version still being tested in transfers from Kashima to Haystack and Ny-Alesund to Haystack (delayed by network availability at Haystack); 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; - VSI-G: draft data format for 10GigE has been distributed Progress towards routine e-VLBI: - Intensive data from Wettzell, Ny-Alesund, and Tsukuba routinely transferred by e-VLBI - Wettzell network bandwidth increased from ~32 Mbps to ~500 Mbps - Ny-Alesund network bandwidth ~80 Mbps; may be increased to ~300 Mbps, but uncertain - all data from Tsukuba and Kashima transmitted via e-VLBI - all Syowa data transferred via e-VLBI from Japan - serious efforts underway to connect Kokee at >= 1 Gbps, but may take a while - Fortaleza to be connected by ~Dec 07, speed not clear - MPIfR correlator connected at 1 Gbps - serious efforts underway to connect USNO at >= 1 Gbps; schedule uncertain - Haystack 10GigE connection to D.C. undergoing testing and debugging, should be operational RSN The next International e-VLBI Workshop is at MPIfR Bonn, 17-18 Sep 2007. 60 attendees registered. The following e-VLBI workshop is expected to be in Japan in fall 2008. 4.7 V2C extended report (Bill Petrachenko and Arthur Niell) The goals of the next generation VLBI system are: - 1 mm position and 0.1 mm/a position rate accuracies - continuous observations - short turnaround between observations and initial results (less than 24 hours) The main thrusts of the V2C lay on simulation and prototyping efforts. Monte Carlo simulators have been developed to predict VLBI2010 performance; to study the impact of strategies, system parameters, specifications; and to understand the error processes. The NASA supported prototyping efforts focussed on testing the "broadband delay" concept and on gaining real world experience with the next generation VLBI subsystems. The slew rate specification for the new antennas shall be fixed by the end of 2007. The VLBI2010 system shall be fully defined by 2010. Hayo Hase inquired about investigations of twin telescopes. Bill replied that only theoretical investigations have been done in the sense that, for instance, two 12-m antennas are to be favored over one 16-m antenna. The power consumption and the stress on the antenna due to continuous and high-density observing was not taken into account so far. Harald added that twin telescope analysis is not included in the software packages yet. Arthur Niell reported on the progress of the broadband delay development. The development plan encompasses the feed and receiver, the up-down converters, the digital backends, the high data rate acquisition, the analysis software, and the phase calibration. Broadband feeds will be tested on the Westford to GGAO baseline. 4.8 Joint WG IERS/IVS short report (Chopo Ma) The Working Group met in Vienna, Austria in April and will have another meeting next week (September 2007) in Paris, France. Eight groups submitted time series and several groups provided source catalogues to the ICRF2 ftp area. The data are being compared and discussed. There will also be a Working Group meeting in St. Petersburg in March 2008 in conjunction with the General Meeting. 5. New WG 'Data Structures' (WG4) (John Gipson via telecon) The current IVS standard for data exchange and archiving are databases. In addition, NGS Cards are used. The system was designed to meet hardware and software requirements of the 1970ies/1980ies and was created for Calc/Solve. It was designed for S/X data, has lots of redundancies, and is inadequate for VLBI2010. To define and establish a new data structure several key tasks need to be addressed (among other things): current requirements and limitations, desired extensions/enhancements, a single session data format, the catalog and archiving system, and a detailed transition plan. A proposed timeline is: - present preliminary report at GM2008 - update at EVGA 2009 meeting - final report at GM2010 Hayo Hase noted that automation of processing was not mentioned. John replied that automation is planned and that there are software tools available, e.g. for the netCDF data format. The Board felt that the task is so complicated that the work layout cannot be fully formulated at this point. The initial outline can be formulated now, but it needs to be revisited at appropriate intervals. The planned reports in 2008 and 2009 lend themselves to a rediscussion. The Board voted unanimously in favor of setting up a WG4 on "Data Structures". John Gipson is tasked to formulate the charter/terms-of- reference (in the next four weeks) and establish the group. An interim report is due by the GM2008. 6. Items related to IAG, IAU, FAGS, EVN 6.1 IAG 6.1.1 IAG (Harald Schuh) The 2009 IAG Scientific Assembly will be in Buenos Aires, Argentina; the 2011 IUGG General Assembly will be in Melbourne, Australia. The IAG Council elected the new members of the IAG Executive Committee. Harald is one of the three service representatives, the others being Steve Kenyon and Ruth Neilan. The new president of IAG is Michael Sideris, the new vice-president is Chris Rizos. Herman Drewes is the new IAG Secretary General. 6.1.2 Commission 1 (Chopo Ma) Zuheir Altamimi is the newly elected chair of Commission 1. Harald Schuh is the president of subcommission 1.4 on CRF to TRF relation. Chopo Ma is the IVS representative in the Commission 1 Steering Committee. 6.1.3 IERS (Chopo Ma) The IERS is one of the main users of outputs of the technique services. The IERS is co-organizing the Unified Analysis Workshop in Monterey, CA in December 2007. The combination pilot project is ongoing. 6.1.4 GGOS (Dirk Behrend and Harald Schuh) There was a GGOS Steering Committee meeting in Perugia, Italy on July 9. Harald attended the meeting. The GGOS2020 Reference Document has grown to about 200 pages and is close to be finished. GGOS has been changed from an IAG Project to a (permanent) IAG component. The IAG Services are important contributors to GGOS, but the formal role of the Services w.r.t. GGOS is still under discussion. Wolfgang Schlueter stepped back from his position as Deputy IVS Representative on the GGOS Steering Committee. The Board unanimously voted for Harald Schuh to fill the deputy representative position. Harald accepted his election. 6.1.5 EVGA (Axel Nothnagel) Nothing to report. 6.2 IAU (Patrick Charlot) There are two Meetings coming up: - Journees 2007: Meudon, 17-19 September 2007 - subtitled "The Celestial Reference Frame for the Future" - IAU Symposium 248 "A giant step: from Milli to Micro-arcsecond Astrometry" - Shanghai, 15-19 October 2007 - oral presentations by C. Ma, N. Capitaine, P. Charlot 6.3 FAGS (Dirk Behrend) There were two FAGS meetings since the last board meeting: - FAGS Directors meeting, April 2-3, Paris, France - FAGS General Meeting, July 2, Perugia, Italy Personnel changes: - new secretary: Philip Woodworth - new FAGS Rep on IVS Directing Board: Ray Norris White Paper: - restructuring of FAGS ("new" federation of services) - interrelation with WDC and CODATA - FAGS input the ICSU SCID Committee (Strategic Committee on Information and Data) 6.4 EVN (Patrick Charlot) EVN Consortium Board of Directors (CBD): - new CBD Chair: R. Bachiller (OAN) - new JIVE Director: H. van Langevelde - new directors at Jodrell Bank (S. Garrington), Westerbork (R. Vermeulen), IRA (L. Feretti) - next CBD meeting on 13 November 2007 in Madrid, in conjunction with TOG, RadioNet and JIVE Board meetings Northstar is now the only way of submitting EVN and Global (EVN+VLBA) proposals. Web address: http://proposal.jive.nl EVN policy and techniques: - EVN 2015 document in preparation - new e-VLBI policy: - e-VLBI not restricted to rapid response science - three classes of proposals: standard, triggered, and short (<2 hours) e-VLBI observations - Target of Opportunity (ToO) policy - ToO document prepared - discussed by CBD, not yet made public - waiting for implementation in Northstar - DBBC development ongoing and supported by CBD Meetings: - 37th YERAC (Young European Radio Astronomers Conference) - Bordeaux, 3-7 September 2007 - 50 PhD students (~15% VLBI) - European Radio Interferometry School (ERIS) - Bonn, 10-14 September 2007 - 100 participants 7. Meetings 7.1 Recent Meetings 2007 The proceedings of the 18th EVGA meeting are already published. The online version is available at: http://mars.hg.tuwien.ac.at/~evga/proceedings/ 7.2 GGOS Unified Analysis Workshop (Axel Nothnagel) covered in 4.4 7.3 GM2008 (Dirk Behrend) covered in 4.1 7.4 Next DB meeting (Harald Schuh) - spring 2008: St. Petersburg, Russia, March 8, 2008 - fall 2008: probably in Japan in conjunction with the next e-VLBI meeting 8. Miscellaneous 8.1 Journal of Geodesy, Special Issue "VLBI" (Harald Schuh) Harald thanked Chopo and Axel for their work as editors. 8.2 Other topics None. Next board meeting: March 8, 2008 in St. Petersburg, Russia