Grant-in-Aid for international Scientific Research
|Allocation Type||Single-year Grants|
|Research Institution||National Astronomical Observatory|
KAKUTA Chuichi National Astronomical Observatory, Earth Rotation Division, 地球回転研究系・重力部門, 教授 (50000162)
KAWAGUCHI Noriyuki National Astronomical Observatory, Radio Astronomy Division, 電波天文学研究系・超長基線干渉計天体物理部門, 助教授 (90214618)
SATO Katsuhisa National Astronomical Observatory, Earth Rotation Division, 地球回転研究系・電波地球計測部門, 助手 (90178715)
FUJISHITA Mitsumi National Astronomical Observatory, Earth Rotation Division, 地球回転研究系・電波地球計測部門, 助手 (60141967)
KUJI Seisuke National Astronomical Observatory, Earth Rotation Division, 地球回転研究系・電波地球計測部門, 助手 (40132675)
HARA Tadayoshi National Astronomical Observatory, Earth Rotation Division, 地球回転研究系・電波地球計測部門, 助教授 (60000171)
SASAO Tetsuo National Astronomical Observatory, Earth Rotation Division, 地球回転研究系・電波地球計測部門, 教授 (20000177)
|Project Period (FY)
1989 – 1990
Completed(Fiscal Year 1990)
|Budget Amount *help
¥8,000,000 (Direct Cost : ¥8,000,000)
Fiscal Year 1990 : ¥3,500,000 (Direct Cost : ¥3,500,000)
Fiscal Year 1989 : ¥4,500,000 (Direct Cost : ¥4,500,000)
|Keywords||VLBI / VLBI backend / radio astronomy / antenna / correlator / radio wave propagation|
The purpose of this study is, to research international activities of the VLBI (Very Long Baseline Interferometer) to establish a much more accurate VLBI system in Japan, VERA (VLBI for the Earth Rotation Study and Astrometry).
Investigations have been made in Australia, U. S. A., Canada, Germany, Sweden, Netherland and U. K. Main results are as follows :
1. Antenna and the VLBI system
Old and new large radio telescopes were investigated. Displacements of the reference point of the an tenna and deformations of the optical system of the antenna were well corrected at Wettzell's antenna, Germany.
2. The VLBI hardware systems and correlators
Researches were made on the frontend, frequency standard, phase delay calibrator and optical fiber system. Data acquisition terminals are strongly requested for the capability of compatibility ofthe VLBI backend.
3. Excess path delay (EPD) of the radio wave propagation
The EPD are well determined in the clear-air day. But in the case of rainfall and heavy cloudy days measurements of water vapor in the atmosphere may be determined by VHF, Radio Acoustic Sounding System and the precipitation.
4. International cooperative observation with the VLBI backend K4
Experimental VLBI observations between the DLR, Institute fur Hochfrequenztechnik, Germany with the portable VLBI backend system K4 and the Nobeyama Radio observatory with the backend Mrak 3 have been made and proved the compatibility between K4 and Mark 3.
5. Compatibility of the VLBI backend and study of the correlator
At Haystack Observatory, U. S. A. a new backend Mark 4 is now developing and the Mark 4 correlator has been studied. The United States Navy Observatory has been operating the Mark 3A correlator. It needs management of the VLBI tapes in order to operate the VLBI network smoothly.