Very Long Baseline Connected Interferometry via the STM-16 ATM Network

Hitoshi KIUCHI  Yukio TAKAHASHI  Akihiro KANEKO  Hisao UOSE  Sotetsu IWAMURA  Takashi HOSHINO  Noriyuki KAWAGUCHI  Hideyuki KOBAYASHI  Kenta FUJISAWA  Jun AMAGAI  Junichi NAKAJIMA  Tetsuro KONDO  Satoru IGUCHI  Takeshi MIYAJI  Kazuo SORAI  Kouichi SEBATA  Taizoh YOSHINO  Noriyuki KURIHARA  

IEICE TRANSACTIONS on Communications   Vol.E83-B   No.2   pp.238-245
Publication Date: 2000/02/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (IEICE/IEEE Joint Special Issue on Recent Progress in ATM Technologies)
Category: ATM Switch and System Development
very long baseline interferometry,  STM-16/OC-48,  data synchronization,  virtual telescope,  

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The Communications Research Laboratory (CRL), the National Astronomical Observatory (NAO), the Institute of Space and Astronoutical Science (ISAS), and the Telecommunication Network Laboratory Group of Nippon Telegraph and Telephone Corporation (NTT) have developed a very-long-baseline-connected-interferometry array, maximum baseline-length was 208 km, using a high-speed asynchronous transfer mode (ATM) network with an AAL1 that corresponds to the constant bit-rate protocol. The very long baseline interferometry (VLBI) observed data is transmitted through a 2.488-Gbps [STM-16/OC-48] ATM network instead of being recorded onto magnetic tape. By combining antennas via a high-speed ATM network, a highly-sensitive virtual (radio) telescope system was realized. The system was composed of two real-time VLBI networks: the Key-Stone-Project (KSP) network of CRL (which is used for measuring crustal deformation in the Tokyo metropolitan area), and the OLIVE (optically linked VLBI experiment) network of NAO and ISAS which is used for astronomy (space-VLBI). These networks operated in cooperation with NTT. In order to realize a virtual telescope, the acquired VLBI data were corrected via the ATM networks and were synthesized using the VLBI technique. The cross-correlation processing and data observation were done simultaneously in this system and radio flares on the weak radio source (HR1099) were detected.