Korean VLBI Network (KVN)

KVN+VERA K-band Geodesy Observation

Obtaining accurate antenna positions are important in VLBI system, especially for high precision astrometry. Mizusawa antenna has been participating in international geodesy observations at S/X frequency bands and all VERA stations are measuring their relative positions by K-band geodetic VLBI observations internally. In order to determine and maintain accurate positions of three KVN antennas, KVN and VERA started the K-band geodesy VLBI program in 2011.

Table. The Status of KVN+VERA K-band Geodesy Observations
Obs. Code Obs. Date Antenna Note
r11333k 2011 Nov 29 Ky Ku Kt Vm Vr Vs Vo only VERA+KVN Yonsei solution was obtained
r11361k 2011 Dec 27 Ky Kt Vm Vr Vs Vo observation was failed
r12271k 2012 Sep 27 Ky Ku Kt Vm Vr Vs Vo all solutions were obtained
r13088k 2013 Mar 29 Ky Ku Kt Vm Vr Vs Vo all solutions were obtained
r13140k 2013 May 20 Ky Ku Kt Vm Vr Vs Vo all solutions were obtained
r13251k 2013 Sep 08 Ky Ku Kt Vm Vr Vs Vo in progress
r13313k 2013 Nov 09 Ky Ku Kt Vm Vr Vs Vo in progress
r14028k 2014 Jan 28 Ky Ku Kt Vm Vr Vs Vo in progress
r14095k 2014 Apr 05 Ky Ku Kt Vm Vr Vs Vo in progress

* Ky, Ku, Kt stand for Yonsei, Ulsan, and Tamna antennas in KVN, respectively.
* Vm, Vr, Vs, Vo represent Mizusawa, Iriki, Ishigaki-jima,and Ogasawara antennas in VERA, respectively.

At present, KVN antenna position was measured by using two dual-band GPS antennas (see the section, "GPS measurement") and has been used for KVN(+VERA) VLBI observations and K-band geodetic VLBI observations. The geodetic VLBI solutions were not applied to KVN antenna positions yet since they are still undergoing testing and confirmation.
The accuracy of GPS measurement is approximately about 5 cm and the typical 1-sigma errors of geodetic solutions analyzed by Dr. Jike (Mizusawa observatory, VERA) are about 0.4 cm in X, Y, and Z directions for one successful measurement.
We are regularly monitoring KVN antenna positions using GPS and geodetic VLBI observations.

KVN K-band Geodesy Observation

The first KVN K-band geodesy VLBI was performed on Feb. 1, 2012. Total 85 ICRF sources were observed with 1 Gbps (256MHz bandwidth) data rate. The correlation has been done with DiFX software correlator and the data analysis is in progress.

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Korean VLBI Network (KVN)