Plans for QTT Overall Introduction Wang Na Xinjiang Astronomical - - PowerPoint PPT Presentation

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Plans for QTT Overall Introduction Wang Na Xinjiang Astronomical - - PowerPoint PPT Presentation

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Plans for QTT Overall Introduction Wang Na Xinjiang Astronomical Observatory, CAS May 19-21,2014 Green Bank Outline Background General Plan QTT Site Science Goal Technique Schemes Progress 2014-5-19 3rd US-China

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SLIDE 1

Plans for QTT —Overall Introduction

Wang Na

Xinjiang Astronomical Observatory, CAS

May 19-21,2014 Green Bank

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SLIDE 2

Outline

  • Background
  • General Plan
  • QTT Site
  • Science Goal
  • Technique Schemes
  • Progress

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SLIDE 3

Background

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  • Almost all of our knowledge about the universe are based on the

received electromagnetic radiation by the observer, only a small part are from real material (such as meteor)

  • The transmission window of the atmosphere for radio frequency:

10MHz ～ 1THz（30m ～ 0.3mm）

  • Radio wavelength spanning: λmax/λmin ～ 3×104
  • Optical: λmax/λmin ～ 2
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SLIDE 4

SKA SKA，低频阵列，预研 GM GMRT低频阵列，印度，1998 1998

ALM ALMA，高频阵列，美国，2010

2010年

Background

Giant single telescopes

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中国，FAST 5 500米，在建 美国 305 305米，1963 1963年

Arrays

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SLIDE 5

英国76 76米，1958 1958年 澳大利亚 64 64米，1961 1961年 德国100 100米，1972 1972年 美国100 100× 110 110米，2000 2000年

Fully steerable telescopes

Background

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SLIDE 6

Background

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佘山25 25米，1987 1987年 南山25 25米，1993 1993年 密云50 50米，2005 2005年 昆明40 40米，2006 2006年 上海65 65，2012 2012年

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SLIDE 7
  • QiTai radio Telescope (QTT)

– Steerable 110m radio telescope

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General Plan

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SLIDE 8

General Plan

  • Features

– Prime/Gregorian paraboloid, Az/El – Aperture: 110 m – Fully Steerable – Active Surface – Freq Range 150 MHz – 115 GHz

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SLIDE 9

General Plan

  • Chin

China V a VLBI (CV (CVN): astrometry, space exploration CVN+QTT: sensitivity increases 1.8 times CVN+QTT+65m: sensitivity increases 3 times

  • EV

EVN

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Ban and (c (cm) EV EVN Avai ailab able T Tele le SEFD FD ( (Jy Jy) ) (NS 25 25m) SEFD FD ( (Jy Jy) (QT QTT) Rat atio impro roveme ment

18 10 13 9 30% 13 8 61 17 71% 6 10 14 12 16% 3.6 8 31 21 34% 1.3 6 149 101 33%

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SLIDE 10

General Plan

  • Sur

Surfa face Accu Accuracy ( y (rm rms): : – main reflector: ≤0.6mm (no active surface) ≤0.3mm (active surface, long term ≤0.2mm) single panel:≤ 0.07mm – sub-reflector: ≤0.1mm single panel:≤0.05mm

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SLIDE 11

General Plan

  • Pointing Accuracy @ 6m

6mm wa wave length with wind speed≤4m/s, temperature drift≤2℃/h,

  • bservation time: 69.5%

– blind pointing≤5arcs – repeatability precision≤2.5arcs

  • QT

QTT T Electr tric ic P Perfo forman ance ces

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Band 100cm 30cm 5cm 1cm 6mm 3mm Efficiency (Optimum El.) 60% 63% 63% 60% ~50% 54% ~30% 30% ~12% System Noise (K) 30 25 20 20 45 100

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SLIDE 12

General Plan

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Type Band (cm) RF Freq (GHz) Focus Feed Poln Science Goals Single Pixel 100 0.15 – 0.6 Primary Kildal Linear Pulsar, RRT 30 0.6 – 4 Primary Horn Linear Pulsar, RRT, HI, OH, Galaxies 5 2 – 12 Greg. Horn Linear Molecular spectrum, Galaxies; VLBI 1 12 – 36 Greg. Horn Linear Pulsar, H2O, NH3, VLBI 0.6 36 – 50 Greg. Horn Linear Molecular spectrum, High-z CO 0.3 72 – 115 Greg. Horn Linear Molecular spectrum, Galaxies Dual- Band 13/3.6 2.2 – 2.5 8 – 9 Greg. Horn Circular VLBI, space exploration, System measurement (3.6cm) 3.6/0.9 8 – 9 30 – 34 Greg. Horn Circular VLBI, space exploration Multi- Pixel 15 1 – 2 Primary PAF Linear Pulsar, RRT, HI, OH, Galaxies 0.6 36 – 50 Greg. Horn (multi Beam) Linear Molecular spectrum, Galaxies

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SLIDE 13

QTT Site

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Shihezi Village Qitai Nanshan Urumqi Ulastai

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SLIDE 14

QTT Site

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  • 1.5 km ×2 km basin
  • Altitude range from 1730 m to 2250 m
  • Surrounding ridges form an isolated layer with outside region
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SLIDE 15
  • Elevation of mountain shelter

QTT Site

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SLIDE 16

QTT Site

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  • Average annual rainfall of area:

– 180 to 200 mm

  • Average evaporation capacity of Xinjiang area:

– ~2000mm

  • Atmosp

sphe heric ic wate ater vapour ur cont ntent nt: – Summer: ~19 mm – Spring and Autumn: ~9mm – Winter: ~3 mm

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SLIDE 17

QTT Site

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  • Temper

perature e range: – max +29.3 °, min－26.6 °

  • Temper

perature e drifting:

Temperature drifting Ratio ≤ 5 ℃/hr 99.0% ≤ 3 ℃/hr 92.7% ≤ 2 ℃/hr 82.7%

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SLIDE 18

QTT Site

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Roses diagram

  • Freque

uency distr y distrib ibution of m f max.

  • ax. win

ind sp d speed:

Wind speed Ratio Qitai_Day Qitai_Night Qitai_Average GBT ≤4m/s (3 beaufort scale) 48.9% 83.0% 65.9% 45.9% ≤6m/s (4 beaufort scale) 74.3% 92.9% 83.6% 64.5% ≤8m/s (5 beaufort scale) 91.0% 96.6% 93.7% 79.2% ≤10m/s (6 beaufort scale) 96.7% 98.3% 97.5％ 88.9％ ≥17m/s (8 beaufort scale) 0.21% 0.06% 0.14% 0.5%

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SLIDE 19

QTT Site

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  • RF

RFI: I: S SKA-FAST AST measurement and processing stan standa dards

  • Most

t interference are recognizable:

− Measured 150 MHz ─ 13 GHz − 2 or 3-G mobile wireless communication (UHF, L, S band) − broadcast television (analog digital, VHF, UHF band) − differential rotation system of wireless satellite television (UHF, C band) − satellite navigations

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SLIDE 20

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Science Goal

Astr Astronomy

  • Molecular spectra observations
  • High precision pulsar timing
  • Active galactic nuclei
  • Dark matter
  • VLBI astrometry, astro-dynamics and space

VLBI

  • Sky survey: detecting organic molecule and

sulphur chain molecule

Applic icatio ation

  • VLBI orbit measurement for space exploration
  • Pulsar time standard
  • Deep space pulsar autonomous navigation

NASA/GSF C

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SLIDE 21

Science Goal

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(Lyne, 2010)

High precision pulsar timing

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SLIDE 22

Science Goal

Grav avit itat ational al w wav ave de dete tect ction

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PSR J1045-4509, DM correction, reduces residual by ~50%

20cm 50cm

PSR J1744-1134, polarization correction, residual reduces from 487 to 195ns

NANOGrav, IPTA, PPTA Best: ~50 ns

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SLIDE 23

Science Goal

  • Follow up

up obs.

  • s. o
  • f

f FAS AST p puls ulsar ar sur survey y

  • Sp

Spectrum sur survey at y at 6mm & & 3mm

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SLIDE 24

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Gen ener eral

  • Structure design: high antenna efficiency
  • Servo control: accurate pointing
  • Active surface: quasi closed-loop control
  • Track: welded track + heavy load
  • Structure and electronics: temp under －30℃
  • Rx: wide band feed
  • Multi-beam / PAF

15° ring1…… ring22 15°

5m2, 2856 12.5m2, 888

Technique Schemes

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SLIDE 25

Technique Schemes

Tele lesc scope e effici fficiency – Conformal design – Homology design – Active surface

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Frequency (GHz) Aperture efficiency Gain (K/Jy)

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SLIDE 26

Technique Schemes

Activ Active sur surfa face

  • Deformation:

– Gravity, thermal, temperature drifting, wind load

  • FEM to Quick measurement: OOF
  • Closed-loop control

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GBT：25mins at Q-band 25m

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SLIDE 27

Technique Schemes

Wheel-track antenna mount: 4 or 6 feet support

  • Max. load

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SLIDE 28

10 20 30 40 50 60 10 20 30 40 50 60

Technique Schemes

Segmented main surface – Single joint, 27 rings, ～4000@4m2 – Secondary joint

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1x2 strut 2x2-1 strut 2x2-2 strut 1x3 strut Panel : Back sub-truss 1:1.53 1:1.27

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SLIDE 29

Technique Schemes

Pointing correction

  • Thermal deformation
  • Temperature deformation
  • Wind load

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Technique Schemes

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Increase the resonance frequency Increase the rigidity, reduce structure transmission impassable range Reduce the systematic and random error of servo system PI regulator+ Front feed compound control(FF)+ LQG

Digital control

sys Compound control technique Low speed large torque drive

Telescope control

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SLIDE 31

Technique schemes

Welde lded w d whe heel tr l track ack – Heavy load: ~5000 ton – Temperature range－30—+30℃

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Technique Schemes

Sub Sub-refl flecto ctor – carbon fiber – 6-pole adjust system – Rotate to change Rx

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SLIDE 33

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Technique schemes

Four ridge feedBW: 10 octave band

  • Better radiation pattern
  • High-pass filter

ELEVEN feed

  • Simplify structure
  • Compact, low cost
  • Stable phase center
  • Constant beam width

Ultra-wideband feed – Increase S/N – Simultaneous multi spectrum line obs.

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SLIDE 34

Technique Scemes

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Soft ftwar are

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SLIDE 35

Progress

  • Leading group by

Nuer Baikeli (Chairman of XJ) Bai Chunli (President of CAS)

  • Leading group office / Site headquarters

Liu Hua (secretary of XJ government)

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Progress

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  • Evaluations organized by CAS & NAO
  • Ceremony for laying foundation
  • Manufactures involved
  • Design
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Progress

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2012 Nov. 29—Dec. 1 QTT International Advisory Workshop Suggestions about conceptual design, 3mm science,

  • perating, cost
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International collaboration:

– NRAO: Memorandum of Agreement for Scientific and

Technical Consultation on the Planned Qi-Tai Radio Telescope (QTT)

– KASI, NAOJ, MPIfR

Progress

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SLIDE 39

Progress

Infrastructure

– Land acquisition: approved – Herdsman relocate: 130 families, move in 3 years – Classified road: build this year – Power: satisfy the infrastructure requirement – Water supply plan: assessed – Fiber connection: done for construction period – RFI & meterological daily monitoring

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Progress

Site planning

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QTT Site - Radio Protection Area

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radio quiet zones @different protection levels: – core area – restricted area – coordination area

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SLIDE 42

Progress

Recent – Project Approval Intension: Qitai Station for Astronomical Observation and Popular Science Education – Funding from XJ this year

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Summary

  • QTT: general purpose telescope
  • Site is good for 6mm and above
  • Engineering specifications: 6mm
  • Design aimed to 3mm
  • Technique challenges: structure, pointing control, surface

accuracy, active surface adjust, wideband Rx

  • Science: pulsars, spectrum line, AGN, VLBI
  • Present: infrastructure construction moving on
  • Pursue for approving by 13th 5-year plan

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