4:30 PM - 4:45 PM
[SGD01-23] Current status of Ishioka VLBI station
Keywords:VLBI, Co-location
The International VLBI Service for Geodesy and Astrometry (IVS) promotes VLBI Global Observing System (VGOS; Petrachenko et al., 2009), which is part of Global Geodetic Observing System (GGOS). The Ishioka VLBI observation station (Ishioka station) meets the VGOS requirements and participates in IVS international observations. The goals of VGOS are to achieve: 1-mm position accuracy on global scales, continuous measurements for time series of station positions as well as Earth Orientation Parameters, and turnaround time to initial geodetic results of less than 24 hours. To achieve these goals, the VGOS stations should be equipped with antennas with high slewing rate, receivers for broadband observations (2-14 GHz) and high speed recording systems up to 32 Gbps. Currently, because the number of VGOS stations is not sufficient, IVS conducts both of VGOS observations and legacy S/X observations. The Ishioka station participates in VGOS observations for several month every year and participates in legacy S/X observations for the rest of the period with switching its observation system.
The Ishioka Station uses two different types of receiver depending on a type of an observation: tri-band feed for S/X observations and QRFH for VGOS observations, and it is necessary to replace receivers when switching types of observations, which takes about one week. It is difficult to switch the observation type frequently. So the Geospatial Information Authority of Japan (GSI) improve the QRFH to be able to observe the S-band (2-3 GHz) to participate in S/X observations with it in 2020. By introducing superconducting filter, it became possible to receive signals in the S-band while suppressing strong RFI and fringes were detected in S/X test observations with domestic and international stations. Since July 2020, the Ishioka station has participated in IVS VGOS sessions with the improved QRFH and fringes were detected in them. For participation in IVS S/X sessions, it is necessary to convert the linearly polarized signal received with QRFH to circularly polarized signal to process the observation data at IVS correlators. To solve this obstacle, we will work on it.
Ishioka Geodetic Observation station is one of the GGOS sites which have a VLBI observation station (Ishioka Station) and GNSS stations. The GNSS station “ISHI” is one of IGS stations and its data is sent to them. As a GGOS site, GSI conducts co-location survey to determine the local tie vector between VLBI and GNSS on a regular basis. Since 2015, four co-location survey have been conducted at Ishioka. To contribute to construction of ITRF2020, GSI is preparing to submit the result of co-location survey in 2018 and 2020 to IERS (as of January 2020). This is the first time for Ishioka to submit the result of the co-location surveys.
This talk will summarize activitiese of the Ishioka Station as a VGOS station and a GGOS site.
The Ishioka Station uses two different types of receiver depending on a type of an observation: tri-band feed for S/X observations and QRFH for VGOS observations, and it is necessary to replace receivers when switching types of observations, which takes about one week. It is difficult to switch the observation type frequently. So the Geospatial Information Authority of Japan (GSI) improve the QRFH to be able to observe the S-band (2-3 GHz) to participate in S/X observations with it in 2020. By introducing superconducting filter, it became possible to receive signals in the S-band while suppressing strong RFI and fringes were detected in S/X test observations with domestic and international stations. Since July 2020, the Ishioka station has participated in IVS VGOS sessions with the improved QRFH and fringes were detected in them. For participation in IVS S/X sessions, it is necessary to convert the linearly polarized signal received with QRFH to circularly polarized signal to process the observation data at IVS correlators. To solve this obstacle, we will work on it.
Ishioka Geodetic Observation station is one of the GGOS sites which have a VLBI observation station (Ishioka Station) and GNSS stations. The GNSS station “ISHI” is one of IGS stations and its data is sent to them. As a GGOS site, GSI conducts co-location survey to determine the local tie vector between VLBI and GNSS on a regular basis. Since 2015, four co-location survey have been conducted at Ishioka. To contribute to construction of ITRF2020, GSI is preparing to submit the result of co-location survey in 2018 and 2020 to IERS (as of January 2020). This is the first time for Ishioka to submit the result of the co-location surveys.
This talk will summarize activitiese of the Ishioka Station as a VGOS station and a GGOS site.