e-VLBI Meeting
Current List of Abstracts

Author(s): Steven Bernstein, Lorraine Prior, James Calvin, and Vineet Mehta
Submitter's e-mail: stevenb@ll.mit.edu
Affiliation: M.I.T. Lincoln Laboratory
Title: Glownet and Bossnet Gigabit Network Infrastructure for e-VLBI
Oral Presentation

Abstract: Glownet (Gigabit Lincoln Optical WDM Network) and Bossnet (Boston South optical Network) are providing metropolitan and wide-area gigabit/sec network connectivity respectively for real-time e-VLBI. Each network operates over "dark fiber" leased from commercial providers. Glownet networking equipment uses off-the-shelf hardware to connect Haystack Observatory, MIT Lincoln Laboratory, the MIT campus and the Bossnet terminus in Boston. Whereas Bossnet, reaching about 1000 km from Boston to Washington DC without data regeneration, requires the use of custom designed optical transmission techniques and components. Each network conveys data in standardized gigabit Ethernet and/or SONET OC-48 formats. The technology is scalable to multiple e-VLBI gigabit/sec sites spanning the globe. Experiments with Bossnet have shown TCP throughputs of a gigabit/sec between Boston and Washington.

Author: Phil Diamond
Submitter's e-mail: pdiamond@jb.man.ac.uk
Affiliation: Jodrell Bank Observatory
Title: e-MERLIN
Oral Presentation

Abstract: I will describe the e-MERLIN project, concentrating on aspects of the optical transmission design and the progress towards obtaining access to fibre optic cables required to transmit 210 Gbps of data.

Author(s): Noriyuki Kawaguchi and Kenta Fujisawa
Submitter's e-mail: kawagu@hotaka.mtk.nao.ac.jp
Affiliation: National Astronomical Observatory
Title: Connection of Radio Telescopes by Fiber Cables and Challenges using Super-Scinet Network in Japan
Oral Presentation

Abstract: The most efficient way of connecting radio telescopes by fiber optical cables is discussed. In Japan, ten or more radio telescopes are possible to operate for VLBI observations. I will show traffic burden on communication lines of the radio telescope array composed of 10 radio telescopes or more on different configuration, star connection, line and ring connections. I also show the results of a round-trip experiment performed in Nobeyama radio observatory in February, 2000. Following the basic technical experiment, a new challenge of connecting large aperture telescopes by using a "Super Scinet" network, now under construction in Japan. I will present brief summary of this plan.

Author(s): Junichi Nakajima, Yasuhiro Koyama, Mamoru Sekido, Moritaka Kimura and Teturo Kondo
Submitter's e-mail: nakaji@crl.go.jp
Affiliation: CRL, Kashima Space Research Center, JAPAN
Title: PC-VSI, PC adapted VLBI Standard Interface and ubiquitous Gbps VLBI
Oral Presentation

Abstract: Combining popular PC technology and the newly established VLBI Standard Interface, The radio interferometric technology over a long distance will be able to utilized in various field in experimenting radio dish. The VLBI observation system until the last decade had been consist from specially prepared equipment and used only for astronomy, astrometry and geodetic research. The key components used in scientific research are the high-speed data acquisition AD, recording system and standard signals. Recent technology of PC equipped Gbps bus almost enabled us to handle the Gbps data directly. With a broad-band AD and PC based acquisition system, the high-sensitivity observation were put into practice soon. Then small dishes interferometry, once thought inadequate to receive radio star is turn into reality. Detached from scientific research, the VLBI technology has possibility to catch new user in communication who need dish calibration and small dish arrayed application. We are developing a small dish telescope system, which will present the Gbps observation sensitivity and ubiquitous VLBI in the network growth period.

Author(s): Hisao Uose, Kazunari Irie , Sotetsu Iwamura
Submitter's e-mail: uose.hisao@lab.ntt.co.jp
Affiliation: NTT Information Sharing Platform Laboratories
Title: NTT's Ultra High Speed Networking Experiment on Real-time VLBI
Oral Presentation

Abstract: Since 1995, NTT Laboratories have been conducting a joint research project on ultra speed networking with national research institutes including Communications Research Laboratory (CRL), National Astronomical Observatory of Japan (NAOJ) and Institute of Space and Astronautical Science (ISAS). Among many applications tried in the project, the real-time VLBI (very long baseline interferometry) has proved to be benefited greatly from the high performance communications technologies. With the real-time data transmission using high speed communications network, the bottleneck resulted from the limited data rates in the conventional magnetic tape based VLBI system can be removed. Thus, by utilizing the ultra wide bandwidths of the communications network, the performance of the observation system can be upgraded significantly in terms of sensitivity. The dedicated experimental network connects the NTT R&D centers and participating research organizations with 2.4Gb/s circuits, repeaters, ATM (Asynchronous Transfer Mode) Switches and high-performance IP routers. The first real-time VLBI observations system KSP (Key Stone Project) using very high speed ATM technology was achieved in collaboration with the CRL in 1996. Many antennas belonging to our partner organizations are also connected to the network including Nobeyama 45m, Usuda 64m, Kashima 34m antennas in addition to KSPÕs 11m antennas. Extensive research items regarding the real-time VLBI technology are also being conducted on this experimental network, together with the scientific observations. So far, through the experiments using the developed real-time VLBI system, great improvement in observation performance has been achieved. In addition to ATM technology, we've started to use the Internet technologies for sending VLBI data, and successfully conducted a real-time VLBI observation between Usuda 64m and Kashima 34m antennas using our IP transmission system. The transmission speed of the developed system can be easily upgraded because of its modular architecture that splits a high speed data stream into multiple IP sub-streams to be sent in parallel in the network. This will open up a possibility of connecting antennas abroad to our network. Future research plans include distributed data processing using a number of PCs connected to the network, huge data storage for the raw data and international collaborations with other research organizations abroad.

Author(s): T. Kondo, Y. Koyama, J. Nakajima, M. Sekido, H. Osaki, M. Kimura, Y. Ichikawa*
Submitter's e-mail: kondo@crl.go.jp
Affiliation: Communications Research Laboratory, *Nihon Tsushinki Co.Ltd
Title: Internet VLBI system developed at CRL
Poster Presentation

Abstract: The Internet VLBI system developed at CRL is dedicated to taking over current geodetic VLBI system. A geodetic VLBI system usually receives 14 to 16 frequency channels at S and X bands. Each channel data are transmitted independently by using the IP (Internet protocol) technology. Thus, only establishing the system for one channel, we can easily expand it to the multi-channel system, i.e., geodetic VLBI system. We have been developing the system as a PC-based system consisting of a PCI-bus sampler board and PC softwares to make real-time data transmission, reception and correlation. Current status will be presented at the meeting.

Author(s): Dick Ferris
Submitter's e-mail: Dick.Ferris@csiro.au
Affiliation: CSIRO Australia Telescope National Facility
Title: A SONET/SDH Frame Payload Format for Astronomy Data
Oral Presentation

Abstract: It is anticipated that efficient e-VLBI data transmission systems (DTSs) will connect directly to the synchronous telecommunication network. A SONET/SDH frame payload format for astronomy data is proposed at the OC-12/STM-4 level but may be adapted to other levels. It supports but is not restricted to VSI-H DTS operations. The format is designed for efficient implementation in FPGA hardware and may find additional application in wideband DASs and correlators for internal data transmission.

Author(s): Ari Mujunen, Jouko Ritakari
Submitter's e-mail: Ari.Mujunen@hut.fi
Affiliation: Metsähovi Radio Observatory
Title: A simple software architecture and proposed data formats for e-VLBI
Oral Presentation

Abstract: The Metsähovi Radio Observatory VSI-H PC interface board Linux-based device driver and data acquisition software architecture is described, together with proposed data and file formats for straightforward e-VLBI data transmission using conventional TCP/IP-based protocols.

Author(s): Y. Koyama, T. Kondo, J. Nakajima, M. Sekido, M. Kimura, H. Kiuchi, J. Amagai, T. Yoshino
Submitter's e-mail: koyama@crl.go.jp
Affiliation: Communications Research Laboratory
Title: Realtime VLBI experiences and future plans of CRL
Oral Presentation

Abstract: Since its first success in 1997, more than 700 realtime VLBI sessions were carried out with the Key Stone Project stations at Kashima, Koganei, Miura and Tateyama. The introduction of the realtime VLBI system enabled us to perform continuous unattended observations at remote stations and minimized the turn around time from the observations to the final release of the data analysis results. Current efforts of our system developments are focused on the use of Internet Protocol and higher data rate. Especially, the PC based realtime correlation system currently under developments will eliminate barriers among different observation hardware systems. To establish an open platform to which many institutes can contribute for the system developments, we consider it is essential to define a minimal set of standards and requirements for the data stream.

Author(s): Christopher Jacobs
Submitter's e-mail: Chris.Jacobs@jpl.nasa.gov
Affiliation: Jet Propulsion Laboratory
Title: e-VLBI tracking of the Mars Odyssey spacecraft: operational results
Oral Presentation

Abstract: The VLBI group at JPL has used e-VLBI to track the Mars 2001 Odyssey spacecraft. This effort was motivated by a desire to improve angular tracking accuracy. A total of 47 tracking passes were attempted with 100% success. The data were digitized at the antenna site. Typically we recorded 16 Msamples/s of 2 bit/sample data covering roughly 75 MHz spanned bandwidth. The data were networked back to JPL from the three Deep Space Network sites in Goldstone, CA, Canberra Australia, and Madrid Spain at data rates of about 2 Mb/s. The data were correlated using a software correlator running on a Sun workstation, thus eliminating the need for interfacing with a custom hardware correlator as was our practice in the past. The results contributed significantly to the successful navigation of the Mars Odyssey spacecraft. In 2002, we plan to use e-VLBI to measure the Mars ephemeris in the quasi-inertial frame defined by quasars. Our goal is to improve our knowledge of the position of Mars by a factor of 2-5 down to about 1 nrad (0.2 mas). Other near term applications may include the determination of Earth orientation parameters.

Author(s): Yasuhiro Murata
Submitter's e-mail: murata@vsop.isas.ac.jp
Affiliation: The Institute of Space and Astronautical Science
Title:VSOP-2 mission status and the requirements to the future VLBI network
Oral Presentation

Abstract: Following the success of the VLBI Space Observatory Programme (VSOP), a next generation space VLBI mission (VSOP-2) is currently being planned. We expect to have wider bandwidth (at least 1 Gbps) than that of VSOP satellite, to get more sensitivity. We will have 3 observing band, 5-8, 22, and 43 GHz with the dual polarization, the 10 m antenna, and the apogee height of 30,000 km in the current baseline design. We also consider the upgrade options relative to the baseline design. It is no need to say that the ground VLBI is indispensable for the space VLBI mission, as we do in the VSOP mission, and the e-VLBI system will highly affect on the space VLBI mission.

Author(s): Craig Walker
Submitter's e-mail: cwalker@nrao.edu
Affiliation: National Radio Astronomy Observatory
Title: e-VLBI at the NRAO
Oral Presentation

Abstract: Real time VLBI, is of interest to the NRAO for two reasons. First, if the recording system could be replaced with a real time system on the VLBA, some of the major expenses and constraints involved in the operation of the instrument would eliminated. Of course, this would trade against the cost of access to the links, which is currently a big unknown. The second reason is that similar technology will be needed for the second phase of the EVLA project. That phase will include the New Mexico Array (NMA) that will extend the resolution of the VLA by a factor of 10 and fill the UV gap between the VLA and the VLBA. Links of up to several hundred km, with the EVLA bit rate of 96 Gbps, will be required. It will also become possible to integrate the EVLA and VLBA, including using the same correlator for the whole instrument. The fullest integration would require eVLBI links with bandwidths well beyond what is being considered in most current discussions.

Author(s): Sotetsu Iwamura (1), Hisao Uose (1), Kazunari Irie (1), Hitoshi Kiuchi (2), Shin-ichi Nakagawa (2)
Submitter's e-mail: iwamura.sotetsu@lab.ntt.co.jp
Affiliation: NTT Information Sharing Platform Laboratories(1) Communications Research Laboratory(2)
Title: IP Data Transfer System for Real-time VLBI
Oral Presentation

Abstract: We are going to present NTTÕs IP data transfer system for real-time VLBI. The system is based on a parallel IP transfer scheme, where single input ID1 stream is divided and converted to multiple IP streams, transmitted over IP network. At the other end of the network, each IP stream is received and serialized to a single ID1 stream as an output. We implemented the system by using multi-purpose PCs for transmitting and receiving IP data. In addition, to handle ID1 stream, we developed a pair of equipment: one for parallelizing and the other for serializing, each of which is connected to multiple PCs via IEEE1394 interfaces. Our system features low cost and transfer rate scalability up to 256 Mbits/sec, by using parallel transfer with PCs. Using the system, we conducted an experiment of real-time VLBI observation with Kashima antenna (Communications Research Laboratory) and Usuda antenna (Institute of Space and Astronautical Science). In the experiment, observed data was transferred with IP at the data rate of 128 Mbits/sec (32 Mbits/sec x 4 streams) from Usuda to Musashino (NTT Research and Development Center) where a cross correlator was installed. From Kashima, observed data was transmitted by asynchronous transfer mode. We successfully detected a fringe. This experiment is the first IP-based real-time VLBI in the world.

Author(s): Christoper Jacobs, et. al.
Submitter's e-mail: Chris.Jacobs@jpl.nasa.gov
Affiliation: Jet Propulsion Laboratory
Title: A Software Correlator
Poster Presentation

Abstract: Historically, VLBI signals have been correlated using custom designed hardware in order to achieve the desired throughput rates. Continued rapid advances in general purpose computing have brought workstation performance to the point where it is now practical for some applications to correlate VLBI data using general purpose workstations. This poster will report on a software correlator which has been in use at JPL in support of differential VLBI measurements of spacecraft position.

Author(s): Steve Parsley
Submitter's e-mail: parsley@jive.nl
Affiliation: JIVE
Title: VLBI participation in next -generation network development.
Oral Presentation

Abstract: The EVN data processor at JIVE will shortly be connected directly to the Amsterdam Internet Exchange at the Amsterdam Science and Technology Centre (WCTW), via a 2-colour, 2Gb/s optical-fibre link. The connection contract will be placed by SURFnet who are also negotiating a connection from the Westerbork array to JIVE/ASTRON. Co-located at WCTW are computer-scientists and particle physicists who are engaged in various international projects to develop research networks and computational Grids. These projects need bandwidth-hungry applications to act as test-beds for next-generation network infrastructure. VLBI is recognised as an interesting and suitable case which has unique requirements for network loading and Quality of Service. In the UK similar contacts between astronomers, particle physicists and grid/network developers have succeeded in placing VLBI on the agenda of various network development fora. The idea of creating a real-time interferometer between Jodrell Bank and Westerbork using the JIVE data processor to correlate the data is now receiving serious attention. I will talk about the current status of this initiative.

Author(s): Alan Whitney
Submitter's e-mail: awhitney@haystack.mit.edu
Affiliation: MIT Haystack Observatory
Title: Mark 5 and e-VLBI
Oral Presentation

Abstract: The Mark 5 VLBI data system has been designed to support e-VLBI in several modes at data rates up to 1 Gbps. For example, data may be transferred in real-time from antenna to correlator, or may be disc-buffered at either antenna or correlator or both. A demonstration of 1 Gbps real-time and near-real-time e-VLBI data transfer is being prepared using antennas at Westford, MA and NASA/GSFC in MD, a distance of ~700 km, with data being transmitted to the Mark 4 correlator at Haystack Observatory for processing. The data connection utilizes a combination of dedicated and shared networks including Bossnet, Supernet,MAX and GSFC/HNET. Early results of tests over portions of the network have achieved sustained transfer rates of ~990 Mbps using standard Gigabit Ethernet. This work will be described and results to date presented. We plan to build on this demonstration to extend high-speed data connections to both Europe and Japan in the near future.

Author(s): T. Charles Yun
Submitter's e-mail: tcyun@internet2.edu
Affiliation: Internet2
Title: Internet2 Overview
Oral Presentation

Abstract: e-VLBI will soon start to test the capabilities of global research and education networks across the world; researchers in the United States will look to Internet2 to support their research. This talk will address the process for connecting to Internet2, identify common questions that institutions face as they plan their their research (e.g., who can connect, usage rules, costs), and highlight existing work that leverages Internet2 technologies.

Author(s): James Williams
Submitter's e-mail: william@indiana.edu
Affiliation: University of Indiana
Title: International connectivity opportunities for VLBI
Oral Presentation

Abstract: New connectivity options in Asia, North America and Europe present exciting new opportunities for collaboration among VLBI groups worldwide. This talk details network enhancements in Japan (SuperSINET), between Japan and North America (TransPAC), within North America (StarLight) and globally (GTRN). I also describe new cable construction in Asia (SCCN and AJC cables) which offer new collaboration possibilities. Finally, I discuss non-infrastructure concerns that must be addressed for a global VLBI (or any global R/E initiative) to be successful.

Author(s): Hans Hinteregger
Submitter's e-mail: hhinteregger@haystack.mit.edu
Affiliation: MIT Haystack Observatory
Title: 'Last-Mile' Optical Data Transport Infrastructure for e-VLBI
Oral Presentation

Abstract: Optical technology is developing rapidly and costs are coming down, but 'last-mile' costs are still high. This talk will attempt to look at some of the current technologies, their current costs and projections for the future regarding the 'last-mile' problem. Included will be:

The goal of this talk is to help VLBI stations and correlators understand some of the costs associated with connecting to the global high-speed network. Of course, projects such as LOFAR, SKA, and ALMA have somewhat similar requirements and will use many of the same basic components as e-VLBI, so this information should also be relevant for the broader astronomy community.

Author(s): Alan Blatecky
Submitter's e-mail: ablateck@nsf.gov
Title: Future Directions in Networking at NSF
Affiliation: NSF
oral Presentation

Abstract: The presentation will highlight the current thinking and planning about the future directions of networking for NSF. Although networking technologies and capabilities have quickly evolved, the developments are inadequate to support the emerging information technology needs of science and engineering for the next decade. E-Science requires an array of infrastructure, technologies and capabilities. These capabilities include computational power, large data repositories, extensive ad hoc and distributed sensor networks and arrays, transparent transmission, extraordinary end-to-end performance, systemic security, large-scale interoperability and collaborative tools. It is these new networking capabilities that NSF plans to address so that the next generation of networking will be able to meet the needs of e-science, of grand challenge research projects, and of Peta-scale collaborative applications.

Author(s): Martin Leeuwinga, Ari Mujunen,Steve Parsley,Sergei Pogrebenko,Jouko Ritakari,Arpad Szomoru
Submitter's e-mail: Ari.Mujunen@hut.fi
Affiliation: Metsahovi Radio Observatory
Title: The EVN Gbit/s e-VLBI Data Acquisition and Playback System.
oral Presentation

Abstract: Metsähovi Radio Observatory and JIVE (Joint Institute for VLBI in Europe) are developing a 1Gbit/s data acquisition system in an EVN sponsored collaboration. The system can be used for disk-based VLBI, near-realtime e-VLBI and realtime VLBI and it will be compatible both with the Mk5 and the Japanese Gigabit VLBI systems. The system uses commercial PC hardware and Linux operating system. The only custom components are a VSI-H data acquisition board, and a Data Distribution module, both of which are relatively simple and inexpensive. Data is stored in conventional Linux files, which makes the system especially well suited for e-VLBI. Hardware and software architecture of the platform is described together with issues of connecting such units at stations and at the JIVE correlator to provide transportable disks or optical fibre data transfer between stations and the correlator.

Author(s): John Wroclawski
Submitter's e-mail: jtw@lcs.mit.edu
Affiliation: MIT
Title: Advanced Network Architecture Group
oral Presentation

Abstract: Ten years ago, CNRI's Bob Kahn created the Gigabit Testbed program, and demonstrated that millions of dollars and thousands of people-hours were both necessary and sufficient to deliver gigabit-rate networking to the desktops of a few carefully chosen researchers. Technology has advanced, but high-rate universal networking is not yet the plug-and-play commodity that some had hoped for. I'll discuss where we are in this evolution, under what rocks the remaining dragons are hiding, and some steps that are underway in the networking research community to move us closer to the goal.

Author(s): Kevin Dudevoir
Submitter's e-mail: kdudevoir@haystack.mit.edu
Affiliation: MIT Haystack Observatory
Title: Real-Time Data-Transmission Protocols for e-VLBI
oral Presentation

Abstract: Real-time e-VLBI data-transmission requirements differ in certain respects from some other types of real-time data transmissions. This paper will examine e-VLBI requirements and their match to various existing or proposed real-time IP transmission protocols. Some experimental results will be given.

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Last updated: April 5, 2002