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─рЄр шчьхэхэш : Fri Jul 20 05:44:22 2001
─рЄр шэфхъёшЁютрэш : Sat Sep 6 16:51:10 2008
╩юфшЁютър:
╧юшёъют√х ёыютр: m 63

Australian SKA н Progress & Directions
Peter Hall
Berkeley, July 2001

http://www.atnf.csiro.au/SKA

Australian SKA н Year At A Glance
n

Formation of Australian SKA Consortium
н Executive Committee, Science & Engineering Working Groups now functional н First symposium held Feb. 2001

n

Major National Research Facilities (MNRF) bid
н Submitted May 2001; outcome known August 2001 н Contained proposals for 2 major SKA demonstrators

n n n n

Technical Work
н Significant results in antenna and interference mitigation projects

Site Survey
н First field work completed in Western Australia

Collaborations
н Industry and international SKA joint work increasing

Outreach
н Professional and community

SKA Outreach
n

Professional
н н н н Institution of Engineers national congress `Engineering World' article ITEE Society mailout Spectrum management & community issues
╗ Introducing Radio Quiet Zone concept

n

Government
н н н н Federal parliamentary briefing South Australian Govt. briefing Continuing Western Australian interaction Emerging New South Wales interest

n

General
н Radio, TV, print material
╗ Site tests ╗ Prototype Luneburg Lens

н Local & indigenous community contact

Australian SKA: Some Pictorial Philosophy

Widely separated multi -beaming Wide field-of-view Active interference mitigation Broadband

CSIRO SKA Program н Highlights
n

Antennas
н Luneburg Lens EM design & analysis н encouraging first results н Russian prototype Luneburg Lens н Materials science: Artificial dielectrics & manufacturing ╗ Powders and wires н Phased array collaboration (ASTRON, industry....)

n

Site tests & data visualization
н Initial Western Australia field work н Characterize sites AND contribute to international site selection process

n

Interference mitigation
н Strengths in post-correlation IM н Extending to simultaneous multiple satellite sources (IRIDIUM, GLONASS) н ATCA operational IM goals

N

▐ Poster N & coffee

Luneburg Lenses for SKA

11

Konkur Luneburg Lens
╖ Obtained with PRAO collaboration ╖ Two initial uses: - Verify EM design & analysis - Int Mit reference antenna ╖ Currently under test by CSIRO
Diameter Operating frequency range Gain (12 GHz) Aperture efficiency Sidelobe level (standard horn feed) Focal distance Mass 2r = 0.9 m To 12 GHz 39 ▒ 0.5 dB > 50% < -17 dB 1.5r 90 kg -50 to +50 ░C

(Patented construction process)
Operating temperature range

Konkur Lens: First Results
Amplitude (Ref centre meridian plane)

12 GHz Tests; TV Feed

Far-field Beam

2D Beam (Co-polar)

Directivity ~ 39.3 dBi Raw aperture eff ~ 67% - with 0.5 dB dielectric loss ~ 57%

Industry Link: Advanced Nano Technologies
╖ Collaboration between Advanced Powder Technology (Aust) and Samsung Corning (Korea) ╖ Make particles smaller than thickness of DNA string ╖ Unique chemical, mechanical, optical, magnetic properties ╖ Great potential in artificial dielectrics

Industry Link: CEA Technologies
╖ Canberra based ╖150 employees, $20M turnover ╖Modular S and X-band radars sold internationally ╖Interested in becoming involved in SKA prototyping

25

Practical Interference Mitigation

Before
ATCA, 1500 MHz, Terrestrial Data Link Interference

After

Post-Correlation Interference Mitigation

37

Site Tests н First WA RFI Survey
╖ CSIRO & WA Govt -Private contractor ╖ 27 March н 17 April 2001 ╖"First look" study -Representative RFI at one site -Highlight practical challenges -Compare with spectrum database ╖ Analysis continuing н reports this week

5

Australian SKA Demonstrators
n n

Explore new territory
н Concentrators, signal processing....

Money amounts are small ( ~ $US 10M)
н Careful selection of concepts
╗ Best short-term astronomy best SKA demo

n

Cover "big" and "smart"
н Address hard radio science issues AND н Focus on scaling and cost issues relevant to SKA

n

Integrate with existing telescopes
н Extends host's capabilities н Allows detailed assessment of concept

n

Contribute to 2005 concept assessment

MNRF Bid н The Money Trail
MNRF Bid ($US29M)

Gemini ($18M)

SKA ($11M)

Figures Include 50% Matching Funds

Sydney U. ($0.9M)

CSIRO ($8M)

Swinburne U. ($1.25M)

Molonglo Demonstrator

ATCA Demonstrator, SKA Key Technologies

SuperComputer Simulation, Visualization

5, 10, 21

SKA Demonstrators: What We Propose
n

AT Compact Array demonstrator ($US 6M)
н New 2 GHz F/X correlator
╗ Main short-term "astronomical" deliverable ╗ Complements recent mm- wave ATCA upgrade

н 2 x mini SKA stations
╗ Final number and form TBD ╖ Lenses or phased arrays prime contenders

"Smart"

н 4 m Luneburg Lens ╗ Multi-beaming IM reference antenna using AD
n

Molonglo cylindrical reflector demonstrator ($US 0.9M)
н Multibeaming and advanced DSP

"Big"

n

SKA enabling technology ($US 1.5M)

н Active focal plane/surface arrays, highly-integrated receivers n System simulations & software correlators ($US 1.25M)

5

ATCA Demonstrator

ATCA Demonstrator н Design Decisions
n n

Form of station
н Concentrator (lens) vs phased array

Number & layout of stations
н Balance ATCA gains vs breadth of SKA demonstrator
╗ Calibration issues crucial (min size, ability to adequately test homogeneous elements....) ╖ Potentially powerful `holography' modes

n

Nature of interconnection
н Fibre interconnect н analog or digital? н DWDM demonstrator

n

RF issues
н Should demonstrate highly integrated receiving systems н New photonic sampling scheme

22

Photonic PAM System
Antenna K

A Sub-Array Incorporating Impulse Sampling and Photonic A/D Conversion

Antenna 2 Antenna 1 BASE STATION
High repetition rate, low jitter pulse source locked to station reference clock
Multiwavelength Optical Pulse Source
1 1

Receiving Element

To K Antennas

2 2

3 3

... .

N

1xK

Electro-optic Modulator

Detectors and LPFs
DSP A/D

Short optical pulses sample RF at antenna

N

From K Antennas

..

3 3

Downconversion Fringe Rotation Correlation etc

A/D A/D A/D

2 2

WavelengthDivision Demultiplexer

N

....

3 3

2 2

1 1

1 1

-coded samples separated by filter and digitised in parallel

10, 21

Molonglo Demonstrator
n n

18,000 sq m cylindrical paraboloid Currently:
н 843 MHz operation н Analog beamforming

n

Proposed:
н н н н 300 -1420 MHz coverage Multi-beam line feeds Digital beam formation Versatile FX correlator

n

New observing modes, new science

Australian SKA Directions
n n n

Demonstrator design & construction
н Selection of demonstrator concepts by Dec 2002

More site studies work
н Extension to other states

More R&D in additional key technical areas
н Phased array concept н Highly-integrated RF systems н Photonics
╗ Transport, connectivity, RFI filtering ╗ High speed analog н digital conversion

н Configurations and system simulation...need to un-stall
n n

Engagement of wider astronomy community
н e.g. making the Gemini link real

Expansion of industry and international SKA links
н Artificial dielectrics ▐ prototype Luneburg Lenses н Phased array prototypes, integrated receivers, signal processing...