上海天文台 Shanghai Astronomical Observatory e-VLBI Progress in China Zhang Xiuzhong, team of Chinese VLBI Network Shanghai Astronomical Observatory Chinese

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


Outline

1. Introduction

2. e-VLBI Facility Development in China

3. some e-VLBI Observation results

4. Future Plan for e-VLBI in China


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


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


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


A New Correlator

2006

1993

1987

May 17, 2006

May 11, 2006

Chinese VLBI Network


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


Sheshan

天线


NanShan


Miyun


Kunming


Data processing Center


The network connecting

Urumuqi

Kunming

Miyun

SheShan

City Network Connect

Real Time Corellator80Mbps/1G

35KM firbe Data Process Center in SHAO


New Antenna servo system in Seshan station


New S/X band Cryogenic Receivers in Seshan Station


New S/X band Cryogenic Receivers in Nanshan Station


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


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


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





RFI


The residual delay and delay rate, compare with ESA reconstructed orbit. black for the results with hardware correlator and red for software correlator


residual delay residual delay rate


zero-baseline test results


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


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)


Thank You !

Documents

上海天文台 Shanghai Astronomical Observatory e-VLBI Progress in China Zhang Xiuzhong, team of Chinese VLBI Network Shanghai Astronomical Observatory Chinese