KVN and VERA Array

Array

KaVA consists of 7 antenna sites in VERA-Mizusawa, VERA-Iriki, VERA-Ogasawara, VERA-Ishigakijima, KVN-Yonsei, KVN-Ulsan and KVN-Tamna with 21 baselines(see Figure 1). The maximum baseline length is 2270 km between Mizusawa and Ishigakijima, and the minimum baseline length is 305 km between Yonsei and Ulsan. The maximum angular resolution expected from the baseline length is about 1.2 mas for K bandand about 0.6 mas for Q band. The geographic locations and coordinate of each KaVA antenna in the coordinate system of epoch 2009.0 are summarized in table 1. figure 3 shows examples of uv plane coverage.


Figure 2: The uv plane coverage ( km) expected with KaVA antennas from an observation over elevation of 20. Each panel shows the uv coverage for the declination of 60 (left), 20 (center), and -20 (right).

The average velocities of VERA stations in table 2 are predicted value at the epoch of 01/Oct/2011. Reference frame of these coordinates is ITRF2008. The rates of the coordinates of Mizusawa are the average value of change of the coordinates in September, 2011. The rates of the coordinates of Iriki, Ogasawara and Ishigakijima are obtained from averaging of change of the coordinates from December, 2004 to February, 2011. The 2011 off the Pacific coast of Tohoku Earthquake (Mj=9.0) brought the co-seismic large step and non-linear post-seismic movement to the coordinates of Mizusawa. Co-seismic steps of the coordinates of Mizusawa are dX=-2.0136 m, dY=-1.3795 m and dZ=-1.0721 m. The creeping continues still now, though decreased. The changes of coordinates by the post-seismic creeping are dX=-0.7269 m, dY=-0.5020 m and dZ=-0.2017 m in total from March 12, 2011 to October 1, 2013. Post seismic movements of Mizusawa are very complex. Internal error of coordinates of Mizusawa by polynomial fitting is 5-6mm. But, in a solution, a several centimeter differences arise for every fitting with the increase in geodetic observation data. It is judged that these differences are the uncertainly of the coordinates of Mizusawa.

Table 1:Geographic locations of each KaVA antenna.
East Longitude North Latitude Ellipsoidal Height X Y Z
site [m] [m] [m] [m]
Mizusawa 141 07 57.3  39 08 00.7  116.4 -3857244.4029 3108783.1553 4003899.2638
Iriki 130 26 23.6  31 44 52.4  573.6 -3521719.7674 4132174.6548 3336994.1511
Ogasawara 142 12 59.8  27 05 30.5  273.1 -4491068.6055 3481545.0506 2887399.6815
Ishigakijima 124 10 15.6  24 24 43.8  65.1 -3263994.0413 4808056.3278 2619948.8728
Yonsei 126 56 27.4  37 33 54.9  139 -3042280.9035 4045902.6564 3867374.3087
Ulsan 129 14 59.3  35 32 44.2  170 -3287268.5430 4023450.1448 3687379.9675
Tamna 126 27 34.4  33 17 20.9  452 -3171731.5532 4292678.5258 3481038.7679
Positions are obtained by KaVA K-band geodesy measured on 28 Jan 2014 (MJD: 56685)


Table 2:Station code and average velocity of each VERA antenna.
site ivs2 ivs8 cdp x [m/yr] y [m/yr] z [m/yr]
mizusawa vm veramzsw 7362 -0.1096 -0.0891 -0.0354
iriki vr verairik 7364 -0.0210 -0.0087 -0.0156
ogasawara vo veraogsw 7363 0.0252 0.0250 0.0094
ishigakijima vs veraisgk 7365 -0.0348 -0.0057 -0.0540
IVS 2-characters code
IVS 8-characters code
CDP (NASA Crustal Dynamics Project) code
The epoch of the coordinates is January 01, 2013. Average speed was obtained
from the VLBI data from September 27, 2012 to August 11, 2013.

In the case of KVN, all antenna locations are measured with GPS system. The antenna positions of KVN are regularly monitored both with GPS system and geodetic VLBI observations in collaboration with VERA. No velocity information is available for KVN stations.


KASI logo image

KaVA ( KVN and VERA Array )