Rapid turnaround EOP measurements by VLBI over the internet

Abstract

At present, promptness of the data processing of the international Very Long Baseline Interferometry observations is limited by the time required to ship observation tapes or disks from radio telescope sites to a correlation processing site. It can take more than two weeks to transport all the data tapes to the correlation processing site in typical observation sessions for Earth Orientation Parameter measurements. The e-VLBI technique uses high speed communication networks to transport observation data electrically and it has a possibility to dramatically improve the promptness of the data processing and hence the accuracy of the near real-time prediction of the Earth Orientation Parameters. To realize the e-VLBI observations by using a shared network environment, PC based data acquisition systems and data processing systems have been developed. By using the newly developed system, international e-VLBI sessions were performed twice and a rapid estimation of UT1-UTC in less than one day after the observations was demonstrated by the second session performed on June 27, 2003.