Technology Development in Chinese VLBI Network

Transcription

1 Technology Development in Chinese VLBI Network Xiuzhong ZHANG, Zhihan QIAN, Xiaoyu HONG, Zhiqiang SHEN and Team of CVN Shanghai Astronomical Observatory, CAS 1st International VLBI Technology Workshop, Haystack Oct. 2012

2 In the early time Early 1970s, SHAO started to study VLBI tech. In end of 1978, with several institutes, universities and industry, SHAO s propose about the development plan of Chinese VLBI system was approved by CAS.

3 In the early time (cont.) With this plan, three VLBI stations (with 30m antenna) would be established. Unfortunately, in Year 1980, due to the funding problem, the plan was modified to build Sheshan station first, the build of Nanshan and Kunming was delayed.

4 First Chinese - German VLBI Experiment To prepare to build completed VLBI system, SHAO build a 6 m telescope first. 6 meter test antenna

5 Established Sheshan 25 m Antenna At same time, Shanghai VLBI system was started to build. This was included 25 meter telescope, receiver system (Band :18,13/3.6,6,2.8 and 1.3 cm), MK II correlator and hydrogen atomic clock In 1985, 25 m antenna was configurated in manufactory, (shaanxi). Except normal test, with this antenna, SHAO did three months comet Halley observation Middle of 1986, 25m antenna was started to move to Sheshan station

6 Top left: 25m antenna in manufactory(1985) Bottom left : Set up of 25m antenna ( ) Top right: Shesan 25m telescope (end of 1987)

7 Main events of Nanshan 25 m Antenna May 1987, antenna contract was signed Dec. 1993, the antenna was installed in station Mar. 1994, first international VLBI observation Oct. 1994, official unveiling ceremony

8 Top left: Nanshan Station Bottom left : Group Photo (1994)

9 Some test obs. in Sheshan Station , The first geodetic VLBI test experiment at single X-band with Kashima, Gilcreek and Kauai , The first S/X dual-band geodetic VLBI experiment with Kashima, Gilcreek and Kauai, (NASA Crustal Dynamics Project) , The first mapping VLBI experiment at C- band with EVN stations: Effelsberg, Westerbork, Onsala, Medicina and Torun.

10 The First Successful VLBI Experiment Urumqi 25m Radio Telescope Date: Band: S/X Data acquisition system: VLBI Mark III Station: Urumqi, DSS45, Gilcreek, Kokee, Sheshan Mode: NASA CDP standard (X-8 ch.; S-6 ch.)

11 Oct. 1978, Prof. M. H. Cohen (CIT) visited SHAO

12 IAA VLBI experts visited SHAO(1980) Visit Kashima,CRL(1982) Connect with VLBI experts in the world

13 Team China Team China in Sheshan (1997)

14 Team China in Nanshan (1997)

15 VLBA type Correlator in SHAO(2000)

16 First Fringe (Aug. 2000)

17 Development in 2000s In year 2000, China started again to discuss about the launch of lunar probe The orbit determine of the lunar satellite was a main problem SHAO proposed to use VLBI technology to provide precise angle results for orbiting of our lunar probe. After long time discussion and comparing, our proposal was accessed With this opportunity, we started to improve the performance of Sheshan and Nanshan stations, to build Miyun and Kunming stations These included antenna, receive system, DAS, Clock, Network and the data processing center

18 Chinese VLBI Network (CVN) 2476Km 2158Km 3249Km 1114Km 2460Km 1920Km

19 Shanghai (sheshan station) Diameter:25m Band: L, S/X, C, K (22GHz) Recoding system: MK2, S2, MK3, MK4, Mk5A, Mk5B,DBBC Member of EVN, IVS 19

20 Nanshan Station Diameter:25m Band: P, L, S/X, C, K(22GHz) Recoding system: MK2, MK3, MK4, K-4,K-5, Mk5A,Mk5B,DBBC Member of EVN, IVS 20

21 The Kunming 40-m Radio Telescope Dianmeter; 40m Band : S/X Recording system: Mk5A,Mk5B,DBBC, Hydrogen maser; GPS 上海天文台 Shanghai Astronomical Observatory 21

22 Diameter:50m Band: S/X Recording system: Mk5A, MK5B,DBBC Hydrogen maser; GPS 22

23 CVN--VLBI data processing center Hardware correlator (5 stations) Software correlator (10 stations) Output data: CE-1 format CE-1 data processing: near real time evlbi, in 5 min. delay

24 NEW Receivers (2012)

25 Superconductor Filter feed network Molecular pump Dewar of receiver

26 NEW Receivers Power supply unit of S/X receiver

27

28 Digital Data Acquisition System Since year 2007 started to develop : Chinese VLBI Data Acquisition system (CDAS) Main characteristics: - use 5MHz as standard frequency signal input - four channel Ifs input, bandwidth of each If : 512MHz, - frequency step: 1Hz - two VSI interface to MK5B Disk Array - full compatible FS interface of traditional DAQ (H&S) - PCAL and auto-spectrum output - PCI interface for control - Auto/cross - spectrum checken for any two selected channels

29 Diagram of CDAS

30 PCB and Module of CDAS Main board: 2 x 1GHz ADC + 4 LX160 + cpci + 10/100/1000Mbps network VSI-H interface board VSI-H interface board with 10GE

31 CDAS 16 channels Platform (digital part) 5 Processing Boards One for data Selecting 4 Ifs input, 2GHz total BW 16 Ch. output / VSI-H 2 VSI-H interface 1 / 2 / 4 bit output Dual redundant system

32 CDAS Poly-Phase Platform 1 U Box One main Board 2x512Mhz IF input 1x16x32MHz output with VSI-H 2x16x32MHz output with 10GE (in developing)

33 CDAS in UR

34 Project Timeline of SH65M 2008:funded, contract for the antenna construction 2009: complete design, start manufacturing 2010: ground breaking, foundation completed 2011~2012: antenna costruction. 2012(end): L/S/C/X band test observations, ready for participation in the Chinese Lunar Mission : active surface tested, Ku/K/Ka/Q band test observations 2015: project accomplished, in full operation

35 SH65M telescope

36 VLBI Development in China 1970s VLBI Network Concept 1980s Shanghai 25m 1990s Urumqi 25m 2000s Beijing and Kunming (CVN:4 Ant. + correlator) 南山 QTT Chinese VLBI Network 2010s FAST (500m) + Shanghai (65m) 2020s QTT(110m) + space VLBI 36

37 Five hundred meter Aperture Spherical Telescope (FAST) located in Guizhou Province, southwest of China 4,600 triangular panels and similar in design to the Arecibo Observatory diameter : 500m active surface working frequency will be GHz, pointing precision : 4 asec should be complete by September cost of 700 million yuan

38 FAST Left : FAST optical geometry Right: FAST 3-D model

39 上海天文台 Shanghai Astronomical Observatory QTT:QiTai radio Telescope 110-m diameter fully steerable Active surface system Cover GHz 8 bands (UHF L S X K V W) General-purpose radio astronomy, geodynamics, single-dish, VLBI

40 奇台县 Station

41 Space VLBI Array Road map of Millimeter/submillimeter space VLBI array : Stage 1: Long-mm-wavelength Space VLBI Array, aim to be funded in two 10-12meter Space telescopes, highest frequency 43GHz, to realize 20uas high resolution and good uv coverage together with ground-based telescopes for imaging.

42 Phase 0 (road map) Stage 2: Mm-wavelength Space VLBI Array, aim to be funded in three 12-15meter mm-wavelength Space telescopes (86GHz), to achieve high resolution with ground VLBI telescopes Stage 3: submm Space VLBI Array, aim to be funded after 2026 three-four 12-15meter Submm Space telescopes to acquire ultra-high resolution, great astrophysics breakthrough

43 Phase 0.5 of stage 1 A proposal of stage 1 was selected as possible Prototype Research project. two 10m Space telescopes 43GHz Design for imaging The review report of proposal (June 15, 2011): The scientific purpose will be very good, but it hasn t well studied the technique and engineering possibility, and the design of whole project. Phase years pre-study

44 Phase 0.5 of stage 1 Shanghai Astronomical Observatory should work with scientific Institutes and industry to study sciences and design for the system Two Satellites (10m in diameter) Apogee: km Perigee: 1200 km Inclination: 28.5 deg

45 Phase 0.5 of stage 1 Observing Bands (Dual Polarization LCP/RCP) : X (6-9 GHz) K (20-24 GHz) Q (40-46 GHz) Data Rate: 1.2 Gbps or 2.4 Gbps Ang. Res.: 20 micro-as Pointing : <15 Life time: 3 years 45

46 Key Techniques KT 2 15 Satellite KT3 KT5 Astronomical Receiving Sys. 1.2/2.4Gbps Mass Storage KT 1 10m Antenna KT4 Time & Freq. Standard Ground Receiving & Transmission

47 Looking forward the project will be funded during the period of 2016 to 2020 for pre-phase study, the project is approved in last month (Sept. 2012). 47

48 Thank you for your attention!