上海天文台Shanghai Astronomical Observatory
e-VLBI Progress in China
Zhang Xiuzhong, team of Chinese VLBI Network
Shanghai Astronomical Observatory
Chinese Academy of Sciences
上海天文台Shanghai Astronomical Observatory
Outline
1. Introduction
2. e-VLBI Facility Development in China
3. some e-VLBI Observation results
4. Future Plan for e-VLBI in China
上海天文台Shanghai Astronomical Observatory
1. Introduction
science Year 1970, we started to study and tr
y to develop the VLBI technologies in China;
in Year 1987, 25 m telescope in Sheshan Station
in Year 1994, 25 m telescope in Nanshan Station
a 3m Mobile VLBI station is available in 1999
First fringe of 2 station FX correlator in 2000
上海天文台Shanghai Astronomical Observatory
in Year 2001, started to discuss about lunar
prospect project in China. There are
problems to use current Chinese R & RR
satellite tracking system to do lunar probe
tracking.
a good opportunity for Chinese astronomer to
use VLBI system to do lunar probe tracking
上海天文台Shanghai Astronomical Observatory
With Chinese Lunar Project, we have a chance to
upgrade our VLBI system:
1. two new telescopes ( 50m and 40m )
2. improve the station instruments
3. create a data processing center (include hardware and software correlator)
4. the network for e-VLBI
2. e-VLBI Facility Development in China
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A New Correlator
2006
1993
1987
May 17, 2006
May 11, 2006
Chinese VLBI Network
上海天文台Shanghai Astronomical Observatory
Specifications of Chinese VLBI stations
Name LocationAntenna diameter
(m)
Band
(GHz)
VLBI
Terminal
Network Connect
(Data Rate)Available
SheshanNear
Shanghai 250.3, 1.6, 2.3, 5.0, 8.4, 22
VLBA, MKIV,S2,
MKV80Mbps 1987
NanshanNear Urum
qi 250.3, 1.6, 2.3, 5.0, 8.4, 22
MKIV, K4, MKV
16Mbps 1994
Mobile VLBI
Kunming 3 2.3, 8.4 S2, MKIV 2Mbps 1999
Kunming Kunming 40 2.3, 8.4 MKIV, MKV 16Mbps 2006
MiyunNear
Beijing 50 2.3, 8.4 MKIV, MKV 16Mbps 2006
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Sheshan
天线
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NanShan
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Miyun
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Kunming
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Data processing Center
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The network connecting
Urumuqi
Kunming
Miyun
SheShan
City Network Connect
Real Time Corellator80Mbps/1G
35KM firbe Data Process Center in SHAO
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New Antenna servo system in Seshan station
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New S/X band Cryogenic Receivers in Seshan Station
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New S/X band Cryogenic Receivers in Nanshan Station
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3. e-VLBI Observation experiments
• Narrow band real time test observation with
different spacecraft.
• Different orbit spacecraft have been observed
with VLBI system. i.e. GEO, TC-1, TC-2,
SMART-1, deep space probe
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Spacecraft TT&C Signal Characteristics
Narrow bandwidth
several hundred KHz
Relative strong signal to noise rate
Special signal spectrum
with special structure
The dynamic range of signal amplitude relative large
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SMART-1 tracking with 4 Chinese VLBI stations
Disk ArrayMKV/SH
MKV/sp
MKV/UR
MKV/KM
MKV/BJ Disk Array
Disk Array
Disk Array
Disk Array
HCorr
NET
NET
NET
NET
NET
SCorr
Delay/Delay rate
Delay/Delay rate
Orbiting
16Mbps in real time mode, 256Mbps in non real time mode.
The result delay time: 1.5 – 2 minutes after observe time for 1 min. data
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SMART-1 tracking with 4 Chinese VLBI stations
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SMART-1 tracking with 4 Chinese VLBI stations
RFI
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The residual delay and delay rate, compare with ESA reconstructed orbit. black for the results with hardware correlator and red for software correlator
SMART-1 tracking with 4 Chinese VLBI stations
residual delay residual delay rate
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zero-baseline test results
上海天文台Shanghai Astronomical Observatory
NUMBER MEAN (m) RMS (m) Baseline6462 0.0011/3.0405 1.9539/3.6147 SH- BJ5502 -0.6249/0.9465 1.6972/1.8163 SH- KM5329 -0.7947/-2.5548 1.6538/2.9382 SH- UR5858 0.1180/-1.8950 1.4796/2.3543 BJ- KM5669 -0.0973/-5.2185 1.5870/5.4488 BJ- UR5813 -0.2839/-3.4917 1.0780/3.6433 KM- UR
Red: new results
Green: old results
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Future Plans
Make system calibrate for our VLBI stations
upgrade our network system, depend on the requirement of astronomy, geodesy and
spacecraft tracking
Prepare to do the near real time orbit tracking of CE-1 (Chinese lunar project, will be launched in 2007)
上海天文台Shanghai Astronomical Observatory
Thank You !