Geodetic VLBI experiment at 22GHz band


Current geodetic VLBI experiments are conducted in S/X band. Improvements of precision are desired in the geodetic VLBI. The geodetic VLBI in 22GHz is the one of the solution to this demand, because of following reasons;

The geodetic VLBI needs the phase calibration (PCAL) data for each channel in the observation band. CRL developed a new PCAL equipment in 22GHz band. At 16th February, the geodetic VLBI experiment in 22GHz band was conducted between the Institute of Radio Astronomy (Bologna, Italy) and CRL (Kashima, Japan). The purposes of the experiment are In this experiment, 240 observations were conducted for 40 radio sources. We succeeded in the experiments, band width synthesis and baseline analysis. The r.m.s. values of delay and delay rate residuals were 183ps and 94fs/s respectively. The r.m.s. values were almost the same as the r.m.s. value in standard geodetic VLBI experiments in S/X band because we did not use wide band receiver this time and ionospheric delay corrections. The information of the sources in 22GHz band, such as the correlation flux and the resolution, were obtained on the long baseline (8000km). The relation between the distance (z) and the correlation flux density. The new method to estimate the coherence loss by the atmospheric scintillation is proposed. The data will be useful for the future geodetic VLBI experiments in 22GHz band.

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