KVN and VERA Array

Brief Summary of KVN Geodetic Measurement

KVN antenna positions are measured by using GPS antennas (see Figure 9). Two GPS antennas were installed at both sides of elevation gears and measured their positions for a day. Locations of receiver were determined, and then the invariant point (IVP) was calculated using those two GPS antenna positions and their offsets from the IVP. The accuracy of GPS measurement is approximately about 5 cm.

In order to improve and maintain accurate antenna positions, KVN antenna positions are regularly monitored using GPS and geodetic VLBI observations. The K band geodesy VLBI program between KVN and VERA has been started in 2011 (see Table 8). The typical 1-sigma errors of geodetic solutions are about 0.4 cm in X, Y, and Z directions for a successful measurement. However, the geodetic VLBI solutions were not applied to KVN antenna positions until more measurements are obtained.

Table 8: The status of KaVA K band geodesy observations.
Obs. Code Obs. Date Antenna Note
r11333k 2011 Nov. 29 Ky Ku Kt Vm Vr Vs Vo VERA+Yonsei solution was obtained
r11361k 2011 Dec. 27 Ky Kt Vm Vr Vs Vo Observation 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. 9 Ky Ku Kt Vm Vr Vs Vo in progress
r13313k 2013 Nov. 9 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. 5 Ky Ku Kt Vm Vr Vs Vo in progress
Ky, Ku, and Kt stand for Yonsei, Ulsan, and Tamna antennas in KVN, respectively.
Vm, Vr, Vs, and Vo represent Mizusawa, Iriki, Ishigakijima, and Ogasawara antennas in VERA, respectively.

Figure 9: IVP determination of KVN antennas using two GPS antennas.

KASI logo image

KaVA ( KVN and VERA Array )