KVN and VERA Array

Brief Summary of KVN Antennas

The KVN antennas are also designed to be a shaped-Cassegrain-type antenna with an AZ-EL mount. The telescope has a 21m diameter main reflector with a focal length of 6.78m. The main reflector consists of 200 aluminum panels with a manufacturing surface accuracy of about 65 µm. The slewing speed of the main reflector is 3 ◦/sec, which enables fast position-switching observations(Table 3). The sub-re ector position, tilt, and tip are remotely controlled and modeled to compensate for the gravitational deformation of the main reflector and for the sagging-down of the sub-reflector itself.

Table 1:Geographic locations and motions of each KaVA antenna.
East North Ellipsoidal
Longitude Latitude Height X$^{a}$ Y$^{a}$ Z$^{a}$
Site [] [] [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 2: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.
Table 3:Driving performance of KaVA antennas.
Driving axis Driving range Max. driving speed Max. driving acceleration
VERA
AZ$^a$ $-$90$^{\circ}\sim$450$^{\circ}$ 2.1$^{\circ}$/sec 2.1$^{\circ}$/sec$^2$
EL 5$^{\circ}\sim$85$^{\circ}$ 2.1$^{\circ}$/sec 2.1$^{\circ}$/sec$^2$
FR$^b$ $-$270$^{\circ}\sim$270$^{\circ}$ 3.1$^{\circ}$/sec 3.1$^{\circ}$/sec$^2$
KVN
AZ$^a$ $-$90$^{\circ}\sim$450$^{\circ}$ 3$^{\circ}$/sec 3$^{\circ}$/sec$^2$
EL 5$^{\circ}\sim$85$^{\circ}$ 3$^{\circ}$/sec 3$^{\circ}$/sec$^2$
$^a$The north is 0$^{\circ}$ and the east is 90$^{\circ}$.
$^b$FR is 0$^{\circ}$ when Beam-1 is at the sky side and Beam-2 is at the ground side,
 and CW is positive when an antenna is seen from a target source.



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KaVA ( KVN and VERA Array )