VGOS Intensives Ishioka-Onsala

The VLBI Global Observing System (VGOS) is the VLBI contribution to GGOS. During the last years, several VGOS stations have been established, the VGOS observation program has started, and by 2020 VGOS has achieved an operational state involving eight international VGOS stations. Further VGOS stations are currently installed, so that the number of active VGOS stations will increase drastically in the near future. In the end of 2019 the International VLBI Service for Geodesy and Astrometry (IVS) decided to start a new and so-far experimental VGOS-Intensive series, called VGOS-B, involving Ishioka (Japan) and Onsala (Sweden). Both sites operate modern VGOS stations with 13.2 m diameter radio telescopes, i.e. ISHIOKA (IS) in Japan, and ONSA13NE (OE) and ONSA13SW (OW) in Sweden. In total 12 VGOS-B sessions were planned to be observed between December 2019 and February 2020, one every week, in parallel and simultaneously to legacy S/X INT1 Intensive sessions that involve the stations KOKEE (KK) on Hawaii and WETTZELL (WZ) in Germany. The 1-hour long VGOS-B sessions consist of more than fifty radio source observations, resulting in about 1.6 TB of raw data that are collected at each station. The scheduling of the VGOS-B sessions is done at Vienna University of Technology using VieSched++ and the subsequent steps (correlation, fringe-fitting, database creation) are planned to be carried out at the Onsala Space Observatory using DIFX and HOPS. The resulting VGOS databases are planned to be analysed with several VLBI analysis software packages, involving nuSolve, c5++ and ivg::ASCOT. In this presentation, we give an overview on the VGOS-B series, present our experiences, and discuss the obtained results.