[G07-5] GGOS observations: VLBI

[G07-5-03] Broadband VLBI System GALA-V

^○Mamoru Sekido¹, Kazuhiro Takefuji¹, Hideki Ujihara¹, Tetsuro Kondo¹, Masanori Tsutsumi¹, Yuka Miyauchi¹, Eiji Kawai¹, Hiroshi Takiguchi², Ryuichi Ichikawa², Yasuhiro Koyama², Kennichi Watabe³, Tomonari Suzuyama³, Ryoji Kawabata⁴, Yoshihiro Fukuzaki⁴, Masayoshi Ishimoto⁴, Takahiro Wakasugi⁴, Jun'ichi Komuro², Kenjiro Terada², Kunitaka Namba², Rumi Takahashi², Tetsuro Aoki² (1.National Institute of Information and Communications Technology, Kashima Space Technology Center, Kashima, Japan, 2.National Institute of Information and Communications Technology, Headquarter, Koganei, Japan, 3.National Institute of Advanced Industrial Science and Technology, National Metrology Institute of Japan, Tsukuba, Japan, 4.The Geospatial Information Authority of Japan, Tsukuba, Japan)

We have developed a broadband VLBI system named GALA-V, which is compatible with the VGOS (VLBI Global Observing System) specification. The development contains broadband receiver system, data acquisition system, and up to data processing software for precision delay determination. This system demonstrated sub-pico second precision VLBI delay measurement by one second of observation between Japanese domestic broadband VLBI stations: Ishioka 13m and Kashima 34m. We conducted a series of broadband VLBI experiments between two small telescopes installed at NICT(Tokyo) and NMIJ(Tsukuba) for measurement of clock difference between UTC(NICT) and UTC(NMIJ). Analysis results of these experiments proved that broadband VLBI system enables pico-second precision observation even with small diameter radio telescopes. Weighted RMS of post-fit residual delay were around ten and a few pico-seconds on 1.6m-2.4m antenna pair.　The experiment results suggest that delay precision was improved to a sufficient level by broadband system, and the error of geodetic/clock analysis is dominated by atmospheric delay uncertainty.