Summary Notes from the Ninth IVS Directing Board meeting CNRS, Paris, April 5, 2003, 1000-1830 ================================================================= Summary notes by N. Vandenberg First version April 21, 2003 Revised April 28, 2003 Attending at CNRS: W. Schlueter, N. Capitaine, A. Niell, C. Ma, A. Nothnagel, Z. Malkin, B. Petrachenko, H. Schuh, S. Matsuzaka, Y. Koyama Attending at CNRS as a guest: F. Mantovani Attending via video conference at GSFC: A. Whitney, N. Vandenberg, E. Himwich, K. Kingham 1. Welcome Wolfgang Schlueter welcomed the new board members: Zinovy Malkin and Bill Petrachenko. James Campbell. Wayne Cannon, Paolo Tomasi, and Patrick Wallace (the new IAU representative) could not attend. 2. Election summary and new IAU and IAG representatives Wolfgang Schlueter summarized the election. Kerry Kingham, Shigeru Matsuzaka, and Wolfgang Schlueter were re-elected for a second term, showing the confidence that the Associate Members have that their work on the board has been well done. The at large positions were elected by the board. There were 8 nominations and only 2 positions, so it was a difficult decision. For this meeting, Franco Mantovani was invited to attend to represent the EVN interests. Wolfgang Schlueter expressed thanks to Nicole Capitaine for her service on the board. She organized and hosted two of our board meetings, represented IVS at IAU meetings, and helped get IVS recognized as a service of FAGS. The new IAU representative to IVS is Patrick Wallace. He is involved with astronomical software and the implementation of the new IAU resolutions and he is an expert in observational astronomy. Harald Schuh was elected to the IAG Executive Committee as a representative of the services. This will be very important for IVS to have a representative on the EC. The first meeting of the new EC will be at the IAG general assembly in Sapporo, July 2003. 3. Election of the chair for the next term According to the Terms of Reference, the Directing Board elects a Chair from among its members. Wolfgang Schlueter was elected by acclamation and he accepted the job. 4. Reports and discussion 4.1 Chair's report The Chair's activities since the last board meeting included: a request to GSI to continue K4 intensives; letter of support for a new telescope in Ireland; attending conferences and meetings in Santiago, Korea, and Munich; preparation for meetings in Sapporo (IAG) and Leipzig (VLBI Europe). Some good news is that the FAGS financial support continued for this year. The paper for the IAG meeting at Sapporo is a presentation on "The IGGOS viewed from the Space Geodetic Services", jointly prepared by IVS, ILRS, IGS. 4.2 Coordinating Center report Nancy Vandenberg report on Coordinating Center activities since the last board meeting. The 2003 Master Schedule was released, R1/R4 time delay monitoring continued, and deployment plans for Mark 5 were worked on. The Annual Report for 2002 will be printed and distributed by late April. Two Newsletter issues (December 2002 and April 2003) were completed. Upgrades are being coordinated for Hobart to Mark 5, Svetloe initial observations with the NASA loan of Mark 3, and Fortaleza upgrade to Mark 4/5. Other activities included coordinating the board elections in December/January, web site maintenance, and setting up a new mail system that will help limit spam distribution. Applications for affiliated membership were received from Central Astronomical Observatory (Pulkovo) in St. Petersburg, Russia, operating the Bear Lakes radio telescope, and from Korean VLBI Network. Both groups are interested in being affiliated with IVS during the period before they are able to be active participants in IVS geodetic observing sessions. The board approved their membership. The list of current affiliated members is at http://ivscc.gsfc.nasa.gov/org/affil.html. In collaboration with the IGS and ILRS, proposals were submitted to NASA in response to solicitations. The National Geodetic Observatory (NGO) was proposed to be an umbrella organization in the US for geodetic activities. The INDIGO proposal (Inter-Service Data Integration for Geodetic Operations) was proposed to improve the data delivery of the three services via a seamless archive such as IGS is now using. Nancy Vandenberg and Alan Whitney wrote a Mark 5 deployment memo in January 2003 and recommended an upgrade schedule for stations and correlators. All stations were also encouraged to purchase a supply of disks and 8-pack modules for the geodetic disk pool. Nancy Vandenberg report on activities of the Observing Program Committee (OPC) since the last board meeting. The OPC approved the final version of the 2003 master schedule, and reviewed an article in the December Newsletter about "what's new" in the observing program for 2003. Issues discussed included goals for the R&D sessions in 2003 to address R1/R4 differences, K4 weekend intensives, the usage of the Svetloe station, status of the E3 sessions, and possibilities for S2 intensives. Hayo Hase had requested that IVS provide a plaque that stations could mount on their wall to show that they are an approved IVS station. It was agreed that IVS could provide a certificate to any Permanent Component upon request. The certificate mounting would be the responsibility of the component. Bill Petrachenko asked about how IVS requests time at the stations for observing. As an example, Algonquin did not observe very many scans in CONT02 even though it was a great hardship for them to support the long campaign. It seems that the scheduling is capacity driven instead of purpose driven. Requests for observing time should be accompanied by rationale for the time. Nancy Vandenberg responded that all of the requests for time are derived from numerous simulation results that are carefully examined and discussed by the OPC. Stations for each network are carefully selected based on anticipated results for EOP or TRF. If individual stations require more detailed proposals, the Coordinating Center will be glad to provide what is needed for specific stations or agencies. 4.3 Analysis Coordinator report Axel Nothnagel report on combination efforts. A "rapid" series based on two sessions per week is updated weekly, includes sessions from 1999-recent. A "long" series includes all data, updated quarterly, includes sessions from 1979.6-recent. Two files are produced for each series, one using the IAU1980 models, one for IAU2000. Combination investigations included figuring out how to generate session SINEX files and teaching other analysis centers how to do it. Combinations are being done with the DGFI DOGS software. OCCAM (Kalman filter version) can provide only SINEX version 1.0. It remains to investigate whether the Solve SINEX is really datum-free. R1 and R4 results were compared to IGS results for polar motion, and compared with the long series for nutation. Axel said he cannot support the statement that the R4 sessions are better. This year R1 and R4 seem to be of similar quality. The Analysis Workshop was held over two days at Paris Observatory, 37 participants. Presentations by the Analysis Centers was very useful, there was good exchange of information, improved understanding. Possible future products were discussed such as baseline length and baseline components. Axel Nothnagel will prepare a proposal for the board to consider for a Pilot Project. Chopo Ma reported on the IERS retreat and board meeting. At the IERS retreat, reports were heard from IERS components, Product Centers, and the Central Bureau. External contributions were heard from astronomy, IGGOS, altimetry, new satellite missions, and global gravity field. The Technique Centers report on their services. Working groups met on the second day to discuss issues and a combination pilot project was discussed. At the IERS board meeting a change in the meaning of the IERS acronym was adopted: International Earth rotation and Reference systems Service. 4.4 Network Coordinator report Ed Himwich presented the Network Coordinator report. He analyzed station performance for 2002, including 161 sessions, 991 station days. Consistent with earlier reports, about 121 data days or 12.2% were lost. Data loss does not necessarily reflect things that are under the station's control. The data yield for CONT02 was quite good, better than the average for the year. The most significant problems contributing to data loss are RFI, antenna and receiver problems, track overwriting, and clock problems. A warm receiver is equivalent to 2/3 data loss. RFI losses range from 5 to 20%. The adopted "down station" policy says that if a station is known to be not working then it is not scheduled directly into the schedule but is tagged along. With this approach a station can contribute to data acquisition as soon as it is ready to come back. Clock offset errors in the final UTC value go directly into the UT1-UTC product. The goal from the WG2 report is 2-3 microseconds. The recommendation is that the correlators should use consistent clock and rate offset information, and all should use the same default sets. Chopo Ma reports on the status of site surveys. There is a joint team including Zuheir Altamimi (IGN), Chopo Ma (IVS), Mike Pearlman (ILRS), and Jim Long. Jim Long is providing survey tutorials at major meetings, and has circulated a survey standards document to the community. He will also make the Goddard complete survey document and results available as an example. In May a joint team will travel to Shanghai to participate in their local survey. Discussions are ongoing with HartRAO about their survey. 4.5 Technology Coordinator report Alan Whitney presented the Technology Coordinator report. The VSI-S (software) standard Rev. 1 was approved in February 2003 and will be published in the IVS 2002 Annual Report. Work has started on VSI-E (electronic) with the same group as VSI-S. Issues addressed include formatted vs unformatted data, data multiplexing standards, data ID and time tags. VSI-E will be discussed at the Dwingeloo e-VLBI meeting in May. There are about 30 Mark 5 systems deployed, about 12 are Mark 5A, the rest to be upgraded in the next few months. Hobart will receive its system soon. The first Gbit test of the system is a millimeter astronomy experiment starting tomorrow. CONT02 at Westford used Mark 5 exclusively. Data recovery from two lost disks was 77%, though fine tuning of the correlator filters was required to achieve this. Serious work on the Mark 5B (VSI compliant) will get started once the Mark 5A operation is smoother. Disk media costs are now down to $1.25/GB, half the cost of tape. Disks up to 700 GB, required to support unattended 24-hour sessions, are expected in 2004-5, and 1 TB disks for ~$0.50/GB are expected by 2005. There are 4 phases to the e-VLBI development: Phase 1 is the Mark 5, not completed. Phase 2 is demonstration of Gb/s data transfer which took months of work to tune up the network for the Westford-GGAO demonstration. It will be possible, but difficult, to do real-time correlation due to the need to tune networks. Phase 3 is intercontinental experiments such as the Westford-Kashima demonstration. The significance of this experiment is the use of K5 and Mark 5 and translating data formats. Phase 4 is development of a new adaptive IP protocol. Haystack has a 3-year NSF grant to study this. Most networks are lightly loaded but have bursty high demand users. Haystack hired a full time network research person. Existing and planned continental and global Gbit networks are available that may be used to connect VLBI stations. CRL developments Yasuhiro Koyama noted there is more development going on in the e-VLBI area. CRL has developed K3 and then K4. Now K5 is PC-based and uses disks. Boards sample BBC inputs, 4 channels per board. There are 4 PCs at each station for 16 channels. Data is transferred via ftp to the correlator. The most recent experiment between Westford-Kashima had fringes 28 hours after the last observation. Comparison of results from K4 and K5 show only offsets due to different cable lengths. Future plans include repeating the ftp experiment on Westford-Kashima several times; developing a correlator CPU array system, developing a VSI I/O interface, and development of real-time transfer software. CRL will support a K5 system at Tsukuba for IVS sessions. In the future, Intensives can be Tsukuba(K5)-Wettzell(Mk5). The data can be correlated faster than it can be acquired. S2 status Bill Petrachenko reported on the status of the S2 system. The S2 correlator and recorders were funded by CSA (Canadian Space Agency) for VSOP. CSA support has stopped except for supporting the final correlation backlog to August 2003, meaning that the major source of S2 funding is gone. There are 7 S2 DAS, including 1 used for maintenance. The systems at Kokee and Yellowknife are only used part of the year. A 6-station network could be supported, possibly a 7th if the CTVA was at Penticton. The geodetic DAS (Data Acquisition System) is required, along with the S2 recorder, to support geodetic observing in the E3 network. GSD (Geodetic Survey Division) is under "arms-length" review. GSD is on reduced interim funding until the review is completed. The question being asked is "what is the minimum geodetic infrastructure needed for Canada". 4.6. Pilot project Harald Schuh reported on the pilot project - tropospheric parameters. Seven Analysis Centers contributed: IGG, BKG, GSF, CGS, CNR, IAA, OSO. Data are combined with procedures similar to those of IGS. Offsets between different submissions are as good as +/- 0.2 mm. Results are placed on the IVS Data Centers along with statistical analysis. Feedback to the Analysis Centers helps to improve the results and make them more consistent. Comparisons were made to IGS results for 11 sites. The IVS relative accuracy averages 1.8 mm, IGS relative accuracy is 2.6 mm for co-located sites at identical epochs. There are biases between IVS and IGS results which have to be investigated. Conclusions are that the combination is stable, robust, and accurate; feedback to the Analysis Centers is useful; accuracy is 2-4mm in zenith delay. Wolfgang Schlueter remarked on the impressive results from the pilot project. The board approved the tropospheric parameters as an official IVS product. The agreed name is TROP. Nancy Vandenberg will work with Johannes Boehm to set up the appropriate directories on the data center and web pages for the products. 5. Vision paper 2010 Alan Whitney said that the need for a new vision was encouraged by the need for new frequency bands, RFI, aging antennas, and new data systems. Goals for the new observing program would be unattended observing, global network coverage, electronic data transfer, near real-time correlator. Harald Schuh noted that besides the technology, we also need to consider other aspects of the VLBI data flow like more automated analysis. Alan Whitney will prepare a proposed charter and members for discussion by the board to set up a new working group (WG3). Discussion and approval will be done via e-mail. Wolfgang Schlueter noted that we need to consider the work done by astronomers in these areas. Franco Mantovani said that SKA (Square Kilometer Array) is now in the planning stages, so a connection to their studies would be useful because the timescales are about the same. 6. Meetings At the IUGG meeting in Sapporo, Japan, Wolfgang Schlueter will present a poster on IVS and will be a co-author on the paper by the three service chairs. Nicole Capitaine reported on the plans for IVS-related sessions at the IAU General Assembly in Sydney, Australia. JD16 (Joint Discussion 16) is "ICRS - Maintenance and Future Realization" with topics on the future of UTC, implementation of IAU resolutions for the almanacs, Earth rotation and relativity, precession and IAU2000 resolutions impact and the effect on the services. The TOW (Technical Operations Workshop) was moved from June to September 22-25 at Haystack to avoid conflicts with the June EVN session. The hotel rooms for GM3 in Ottawa in February 2004 will be booked soon. The banquet may be at the Museum of Civilization.