The first year of VERA geodetic experiments. J IKE Takaaki, T AMURA Yoshiaki, M AMABE Seiji, and NAOJ VERA Group VERA Observatory, National Astronomical Observatory of Japan IVS GM 2006. abstract.
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JIKE Takaaki, TAMURA Yoshiaki, MAMABE Seiji, and NAOJ VERA Group
VERA Observatory, National Astronomical Observatory of Japan
IVS GM 2006
The four antennas (Mizusawa, Iriki, Ogasawara and Ishigaki ) constitute the VERA network. The longest baseline is that of Mizusawa-Ishigaki, and its length is about 2300km.
(*) Mainly caused by the interference of artificial radio waves.
Antenna, I/F & back-end are shared with the VERA astrometrical observation system.
We started the geodetic VLBI experiment in November 2004.
These experiments are held twice a month, exclusive of antenna maintenance period、 and succeed this year. The newest experiment was carried out on 07/Jan./2006.
The experiments on the above graph have finished the process of the analysis.
CALC3 and MSOLV play the same role as CALC and SOLVE respectively.
CALC3 Physical Models Setting ------
Celestial Ref. Frame: icrf2000
Terrestrial Ref. Frame : itrf2000
EOP(nutation, wobble, UT1): IERS C04 (daily)
Zenith Atm. Pass Delay: Saastamoinen (1972)
Atmosphere Mapping Function: nhmf
Ocean Tide Loading: GOTIC2, naotide99b
MSOLV Parameters Setting ------
Clock Offset and Rate：
Polynomial fitting in arbitrary epochs at each station.
Zenith Atmosphere Pass Delay ： at every 1 hour & at each station.
Site Coordinates: XYZ at the mean epoch of the observations.
Y= 4132174.6818+/-0.0019m, Vy= 0.0023+/-0.0047m/y
Z= 3336994.2426+/-0.0017m, Vz=-0.0153+/-0.0045m/y
X=-4491068.8212+/-0.0020m, Vx= 0.0227+/-0.0052m/y
Y= 3481544.7934+/-0.0016m, Vy= 0.0133+/-0.0041m/y
Z= 2887399.5814+/-0.0016m, Vz= 0.0105+/-0.0042m/y
Y= 4808056.2854+/-0.0020m, Vy= 0.0206+/-0.0049m/y
X= 2619949.2291+/-0.0017m, Vz=-0.0492+/-0.0041m/y
Typical error ellipsoid obtained from 1 experiment. (scale=mm)
We obtained long term averaged coordinates and rates of Iriki, Ogasawara and Ishigaki antenna reference points at the epoch of 2005.0 from 20 experiments data with about 2mm errors. Size of a typical error ellipsoid obtained from 1 experiment is about +/-2mm in the direction of East-West and North-South, and about +/-7 mm in the vertical direction.
These are linear-fitting solutions of the baseline lengths measured by VLBI and GPS.
Differences of baseline length between VLBI and GPS are about 2cm in maximum.
Differences of rates between VLBI and GPS are also a few mm/yr in almost baselines.
S.D. of VLBI is smaller than that of GPS in all baselines.
Time series of the data used to linear-fitting
This variation is seemed to harmonizes with VLBI’s.
More experiments for a long term ( several years ) are needed to obtain definite conclusion about the variation of baseline lengths.
A summary of specification of VERA internal geodetic VLBI experiments.
Synthetic result of 21 wave elements (M2, S2, K1, O1, N2, P1, K2, Q1, M1, J1, OO1, 2N2, MU2, NU2, L2, T2, MTM, MF, MM, SSA & SA).
Ocean tide loading deformation at Ogasawara Station predicted by GOTIC2 & NAO99b
VERA aims the reveal the structure and dynamics of our Galaxy by measuring 3-D positions and motions of Galactic compact radio objects with 10 micro arc-seconds level accuracy.
VERA Back-end System
VERA AOC Room
The Mitaka FX Correlator
VERA antenna & GPS