Speaker
Description
Tsukuba Correlator/Analysis Center in GSI are involved in correlation and analysis of intensive sessions INT-2 and VGOS-INT-B/C every weekend. We report on the status and changes in VGOS-INT-B/C sessions’ correlation process which has been updated from last year.
One of the large barriers to full automated correlation is the process of short baseline between ONSA13NE and ONSA13SW. In VGOS-INT-B/C, data quality of the short baseline is significantly affected by P-cal signals and noises which both stations have in common. Most of the scans have fringe qualities below 3 or G code when all the 32 channels are applied to the process, and thus, we should manually choose which channels to be removed in each observation. Therefore, we investigated the influences of short baseline in the analysis using nuSolve and concluded that the accuracy of UT1-UTC is equal within 1 sigma level between the results with and without short baseline. Thus, GSI decided to omit the short baseline process after bandwidth synthesis from B25164 (June 14, 2025) after discussing it with other IVS correlators, analysts, and Onsala operators. Currently we proceed to make correlation reports and vgosDBs and submit them to the IVS automatically if the HOPS program can estimate all the "pc_phases_x,y", "pc_delay_x,y", and "pc_phase_offset_x,y". We succeeded in a full automated correlation for the first time in B25185 (July 5, 2025), and the latency was 14 hours 9 minutes, where the data transfer consumed almost 12 hours of them. There still remain some bugs in our automation program, and we are on the way to fixing them. In this presentation, details of some updates in our automation program will be reported.
In the near future, we would like to establish a versatile full automated program which is capable of processing various kinds of intensive sessions as a correlation phase through collecting the data format of each telescope. As an analysis phase, GSI is planning to analyze VGOS-INT-B/C sessions using c5++ provided by Hitotsubashi University, NICT and JAXA in the same way as conducted in INT-2 sessions to perform quality inspection of the vgosDB before submission.
