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 [*]). 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 band and 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 [*]. The geographic locations and coordinate of each KaVA antenna are summarized in Table [*]. Figure [*] shows examples of uv plane coverage.

Figure: The uv plane coverage ($\pm 3000$ km) expected with KaVA antennas from an observation over elevation of 20$^{\circ}$. Each panel shows the uv coverage for the declination of 60$^{\circ}$ (left), 20$^{\circ}$ (center), and -20$^{\circ}$ (right).
\includegraphics[angle=0,width=5cm]{fig-KaVA/fig2a.eps} \includegraphics[angle=0,width=5cm]{fig-KaVA/fig2b.eps} \includegraphics[angle=0,width=5cm]{fig-KaVA/fig2c.eps}

The averaged velocities of VERA sites in Table [*] are predicted value at the epoch of January 01, 2015. Reference frame of these coordinates is ITRF2008. The rates of the coordinates of Mizusawa, Iriki, Ogasawara and Ishigakijima are the average value of change of the coordinates from January 01, 2014 to December 31, 2014. 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=-2.0297m, dY=-1.4111m and dZ=-1.0758m. The creeping continues still now, though decreased. The changes of coordinates by the post-seismic creeping are dX=-0.8574m, dY=-0.5387m and dZ=-0.2398m in total from March, 12, 2011 to Jan, 01, 2015.


Table: Geographic locations and motions of each KaVA antenna.
East North Ellipsoidal
Longitude Latitude Height X$^{a}$ Y$^{a}$ Z$^{a}$
Site [ $^{\circ~\prime~\prime\prime}$] [ $^{\circ~\prime~\prime\prime}$] [m] [m] [m] [m]
Mizusawa 141 07 57.3 39 08 00.7 116.4 -3857244.6475 3108782.9982 4003899.2132
Iriki 130 26 23.6 31 44 52.4 573.6 -3521719.8292 4132174.6212 3336994.1399
Ogasawara 142 12 59.8 27 05 30.5 273.1 -4491068.5584 3481545.0777 2887399.7419
Ishigakijima 124 10 15.6 24 24 43.8 65.1 -3263995.1630 4808056.3180 2619948.7989
Yonsei$^{b}$ 126 56 27.4 37 33 54.9 139 -3042280.9137 4045902.7164 3867374.3544
Ulsan$^{b}$ 129 14 59.3 35 32 44.2 170 -3287268.6186 4023450.1799 3687380.0198
Tamna$^{b}$ 126 27 34.4 33 17 20.9 452 -3171731.5580 4292678.4878 3481038.7252
$^{a}$The epoch of the coordinates of VERA is January, 01, 2015.
$^{b}$The KVN antenna positions are obtained by the KaVA K-band geodesy program on January 24, 2014.




Table: Station code and average velocity of each VERA antenna.
Site IVS2$^a$ IVS8$^b$ CDP$^c$ $\Delta$X [m/yr]$^d$ $\Delta$Y [m/yr]$^d$ $\Delta$Z [m/yr]$^d$
Mizusawa Vm VERAMZSW 7362 -0.1108 -0.0471 -0.0050
Iriki Vr VERAIRIK 7364 -0.0223 -0.0101 -0.0131
Ogasawara Vo VERAOGSW 7363 0.0273 0.0261 0.0126
Ishigakijima Vs VERAISGK 7365 -0.0411 -0.0014 -0.0476
$^a$IVS 2-characters code
$^b$IVS 8-characters code
$^c$CDP (NASA Crustal Dynamics Project) code
$^d$The epoch of the coordinates is January 01, 2015. Average speed was obtained
from the VLBI data from January 01, 2014 to June 10, 2016.

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.


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KaVA ( KVN and VERA Array )