1. Korean VLBI Network (KVN)
and e-VLBI
Y. C. Minh, M.-G. Song, and H.-G. Kim
Korea Astronomy Observatory
Contents
Project Summary
Special System Characteristics
Science Targets
Time Table
System Configuration
Site Construction: Yonsei, Ulsan, Tamna
e-KVN
Busan APAN eScience: Minh, Song, & Kim

2. Busan APAN eScience: Minh, Song, & Kim
Project Summary
For the VLBI study of astronomy,
geodesy, and earth science:
KVN Observatories:
Radio Telescopes of 20m-diameter
VLBI Facilities at Seoul, Ulsan, and Jeju
Receiving Frequencies:
22, 43, 100, 150 GHz
2/8 GHz (for geodesy)
VLBI System:
DAS, Recorder, Correlator
Project Period:
(7년)
Busan APAN eScience: Minh, Song, & Kim

3. Busan APAN eScience: Minh, Song, & Kim
Special System Characteristics
Optimized to mm-VLBI:
High-precision antennas:
- High surface accuracy at GHz
- High slew speed
Multi-channel Frontend Receivers:
- Low noise cryogenic HEMT receivers
- Multi-channel selections: 22, 43, 100, (150) GHz
Flexible and High-speed DAS:
- Selectable 4 IF streams of wide bandwidth
- High sampling rate of 2 Gsps, 4 bits/sample
Hard Disk-based Recorder and e-VLBI Performance
Busan APAN eScience: Minh, Song, & Kim

4. Science Targets: Astronomical Key Projects
Mira variable (Pulsating star)
Diamond & Kemball
mm-VLBI
Insterstellar Maser study:
- SiO: Simultaneous 43, 86, (129) GHz Observations
- H2O, CH3OH maser lines
AGN Study:
- Surveys: Spectral indices at mm-wavelengths,..
- Gamma-ray bursts, X-ray variables,..
Astrochemistry:
- Absorption lines toward compact cores
- Interstellar molecule studies at mm-wavelengths
Gravitational Lensing
- Microlensing,..
Busan APAN eScience: Minh, Song, & Kim

5. Busan APAN eScience: Minh, Song, & Kim
Science Targets
KVN Resolution: ~0.001 arc-second at 100 GHz mm at 500 km distance
Astronomical Targets:
From Cosmology to Solar System:
AGN, Quasar, Radio Galaxies, Jets, Gravitational Lens ,..
Maser Lines: Star-forming regions, Stellar Envelopes ...
Interstellar Molecules, Astrochemistry ...
Geodesic Targets:
Reference Frames: ICRF, ITRF, CORE, ..
Tectonic Motions of Korea: Fault plans, Jeju island, ..
Earth Rotation, ..
Busan APAN eScience: Minh, Song, & Kim

6. KVN Construction Time Table
Site Construction
Antenna Installation
Receiver Development
2002 Ⅳ Ⅰ
2007 Ⅱ Ⅲ
Japan-Korea VLBI
Experiments
Correlator
Development
VLBI Recorder
DAS
2006
2005
2004
2003
2001
Site Selection
Site
Design
Civil Engineering
Works
Building
Construction
KVN Research
Center Const.
Specifications
Contract
Foundation
Installation
Calibration
Preparation
22/42GHz
Rx Manufacturing
2/8GHz
Test
Manufacturing
Software Development
Mk5 Development
KVN Experiment
J-K 43GHz 86
J-K
Busan APAN eScience: Minh, Song, & Kim

7. Busan APAN eScience: Minh, Song, & Kim
System Configuration
KVN
Center
System/Observation Remote Control
Real-time & e-VLBI Operation/Data Synthesis
Frontend Rxs
KVN
Correlator D A S
IF Selector, BBC
H-Maser Clock
Sampler
FIR, Formatter
Recorder
Recorder
Recorder
Recorder
Busan APAN eScience: Minh, Song, & Kim

8. Busan APAN eScience: Minh, Song, & Kim
KVN Antennas
Slew Velocity: 3 o/sec (in AZ, EL)
Operating Range:
AZ: +270 o ~ -270 o
EL: 0 ~ 90 o
Tolerable Wind Speed:
Precision Observation: up to 10 m/s
Maximum Survival Velocity: 60, 90 m/s
Type: AZ/EL, Cassegrain focus
Diameter: 20m
Dish: Aluminum
Total Surface Tolerance: < 150 microm
Busan APAN eScience: Minh, Song, & Kim

9. Busan APAN eScience: Minh, Song, & Kim
Front-end Receivers
Low-Noise Cryogenic HEMT Receivers - 2/8 GHz: Geodesy - 22, 43, 100, 150 GHz: Astronomy - Multi-channel receivers: mm-VLBI: Phase correction
Busan APAN eScience: Minh, Song, & Kim

10. DAS (VLBI Data Acquisition System)
IF Inputs: Simultaneous Selection of up to 4 Ifs, Center Frequency: 3 GHz
Bandwidth: 2 GHz
High-speed Samplers: 2 Gsps, 4 bits per sample
Digital Filters: 16 independent channels, 8/16/32 MHz BW
Busan APAN eScience: Minh, Song, & Kim

11. Busan APAN eScience: Minh, Song, & Kim
KVN Recorder
Hard-Disk Type VLBI Recorder: Mk 5
MIT Haystack Observatory’s Mk5 Project:
Development Consortium ( ):
MIT, NASA, NRAO, JIVE, BKG, MPI, KVN
Specifications:
16 hard discs
maximum recording rate: 1 Gbps (expandable)
Standard PC and IDE hard discs
VSI Interface
KVN Production Plan of Mk 5 (2003~)
Mk 5 Prototype (Mk5p)
Busan APAN eScience: Minh, Song, & Kim

12. KVN Site Construction KVN Observatory Locations :
- Seoul: Yonsei University
- Ulsan: University of Ulsan
- Jejudo: Tamna University
KVN Data Center and Research Center :
- Seoul: Yonsei University
“KVN-Expanded”: a total of 6 antennas
UV coverage and synthesized beam shape of
the KVN+TRAO sites (for the Dec=40o source)
Busan APAN eScience: Minh, Song, & Kim

13. KVN Yonsei Observatory
Busan APAN eScience: Minh, Song, & Kim

14. Busan APAN eScience: Minh, Song, & Kim
KVN Ulsan Observatory
Busan APAN eScience: Minh, Song, & Kim

15. Busan APAN eScience: Minh, Song, & Kim
KVN Tamna Observatory
Busan APAN eScience: Minh, Song, & Kim

16. Busan APAN eScience: Minh, Song, & Kim
e-KVN
KVN: National Facility for VLBI (Very Long Baseline Interferometry)
Data syntheses using the data from remote sites: at present, from 4
sites in Korea, and possibly from foreign countries (e.g. Japan, Europe,
USA, etc.)
To send the observed radio data: it will be very efficient, if using
Information Infrastructures, instead of using postal mail of tapes and/or
hard-disks.
Data Recording rate: 1 Gbps (> 2 Gbps)
Real-time/e-VLBI Operation: > 1 Gbps
Expected total amount of data to be sent: ~ a few Tbyte/day
KOREN:
Busan APAN eScience: Minh, Song, & Kim

17. Status of KOREN Korea Advanced Research Network
Special Features
Service for next generation Internet research environment (1999 ~), no commercial service
Service of latest internet technologies (IP Multicast, IPv6, etc.)
Small amount of annual fees, for research purposes
Data transfer rate: 155Mbps ~ 1Gbps (Local), 2.5 ~ 40Gbps (Backbone)
Equipment: IPv4, IPv6, IP Multicast, IP QoS, WDM, ATM Switches, Routers, Servers
Plan
All over the country: > 2.5 Gbps
Data speed between Korea-USA: 155 Mbps ( )
Data speed between Korea-EU: to 45 Mbps (15 Mbps at present)
Busan APAN eScience: Minh, Song, & Kim

18. Busan APAN eScience: Minh, Song, & Kim
KOREN
Singapore
6 M
TAP
Seoul
GSR
10 M
Europe
USA
45 M
Daegu
GSR
Suwon
GSR
LEGEND
GSR
DWDM
Daejon
GSR
ATM Switch
GSR
Router
Gigabit Switch
40 Gbps
Busan
1 G
2.5Gbps
Japan
155Mbps
> 2.5Gbps(plan)
Gwangju
Busan APAN eScience: Minh, Song, & Kim

19. Busan APAN eScience: Minh, Song, & Kim
TEN-155
CA*net 3
KOREN
Europe
Canada
TEIN
10G
10M
NIO
Seoul
vBNS, Abilene
China
45M
Suwon
USA
StarTAP
Malaysia
Daejon
Daegu
622M×2
Busan 6M
SingAREN
Gwangju
TransPAC
Japan 1G
Singapore 8M
Tokyo-XP
APII Test-bed (Asia Pacific Information Infra.)
WIDE, JGN
TEIN(Trans Eurasia Information Network)
Busan APAN eScience: Minh, Song, & Kim

20. Busan APAN eScience: Minh, Song, & Kim
e-KVN
Configuration
Busan APAN eScience: Minh, Song, & Kim

21. Busan APAN eScience: Minh, Song, & Kim
e-KVN Summary
KVN: VLBI for Astronomy, Geodesy, and Earth Science
- National Project
KVN Data Speed: 1 Gbps (2-4 Gbps at 2007)
Expected Use: ~a few Tbyte/day
Time Schedule for e-VLBI:
- e-VLBI experiment between Japan-Korea: 2004 ~
- e-KVN: 2006 ~
e-KVN:
- Radio Telescope Remote Control
- VLBI Observing Program Execution
- Real-time VLBI Operation: Interferometric fringe test, Real-time image
syntheses
- Domestic e-VLBI (IPoDWDM ?): Observed Radio Data Transfer, Quasi-real-time
Data Synthesis
- International e-VLBI Projects
Busan APAN eScience: Minh, Song, & Kim