KSRC/NICT VLBI software correlator package

After the successful fringe detection on the Kashima--WSRT baseline in April 2003 using a software correlator developed by the Kashima Space Research Centre (KSRC) of the National Institute of Information and Communications Technology (NICT) in Japan (see also the previous news), the correlator was made available to JIVE on a charge-free license in July 2003. This is the first license-based contract between NICT and an international institute. The software correlator at JIVE will be used mainly for quick fringe checks and clock searches in EVN experiments recorded with the Mark5 system. The correlator package is now installed on a Linux machine at JIVE.

Using the data obtained from an EVN test observation made in May 2003 (code D03C1), we obtained nice fringes in the Medicina-Noto-Effelsberg baselines. A fringe-search diagram presents fringe-search windows obtained from data in 2 IFs and 2 polarisations spanning 5 seconds. Left-right and front-back axes indicate delay and delay-rate residual axes, respectively.

At JIVE, using a single PC with a 2-GHz Pentium processor, VLBI data with one 8-MHz base band channel takes approximately 50 times as long as the actual signal-recording duration to process, including conversion from Mark5 to K5 data format. This period (about 5 minutes for 5 seconds of data) is impressive when taking into account that software correlation itself was impossible on a reasonable time scale before a few years ago. Now the software correlator package has perfect compatibility with Mark5 (including mode A) data and VEX schedule files. From the next EVN observing session, small amounts of VLBI data can be sent to JIVE from the EVN stations via ftp to allow regular fringe searches during observing sessions. These should improve the reliability of EVN operations and with the software correlator can be analysed without interrupting operations on the EVN MarkIV data processor.

If you are interested in using the software correlator, please contact Dr Tetsuro Kondo (KSRC/NICT, head of the Radio Astronomy Applications Group, kondo@nict.go.jp).

Dr Kondo will organize the necessary procedures to provide the charge-free license and the correlator package. The users manual of the correlator package is now provided from the NICT webpage. The usage of the package is permitted only for academic research, including radio astronomy and geodesy. If your institute has already made some collaborative contracts with NICT, the procedures will be easier.

If you have any questions about this page, the correlator package at JIVE or the user's manual, please contact Zsolt Paragi (JIVE, zparagi@jive.nl).

JIVE acknowledges Dr. Tetsuro Kondo and his Radio Astronomy Applications Group in KSRC/NICT for collaborating in development of the software correlator for the EVN and in test observations for this purpose, and for providing the software correlator package to JIVE. All copyrights of the software correlator package are reserved by the NICT.