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Feb 2005
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For SKADS Meeting, Amsterdam, 24 February 2005 Overview of Australia’s NTD/SKA Activities for Mileura in WA Presented by: Colin Jacka and John O’Sullivan 24 February 2005
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www.atnf.csiro.au Mileura Site
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www.atnf.csiro.au Mileura, Pathway to SKA 150km Perth 850km Geraldton ~500km
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www.atnf.csiro.au What is Planned for Mileura? Mileura Widefield Array NTD/xNTD (CSIRO led) ― towards Australia’s SKA LFD (MIT Haystack led) ― Aperture Array 100-300 MHz Berkeley Array ― EOR experiment CSIRO (Ron Ekers et al) ― for EOR RQZ ― essential for all of the above
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www.atnf.csiro.au Radio Quiet Zone activities Working with Fed, State & Local govts towards establishing procedures to protect the radio quietness and set up the RQZ With ACA to control licensed transmissions Within 100-300 km coordination zone With WA Govt to control incidental transmissions via DAs Within 30 km development controls RQZ regulations apply only to fixed development & services (not apply to mobiles, aircraft, emergency services, Defence) Signage for mobiles, coordination with Defence, aircraft
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www.atnf.csiro.au SKA Demonstrator in Australia NTD (New Technology Demonstrator) Funded by Australian government and CSIRO as one of the MNRF- (Major New Research Facility) funded projects over the period 2002 – 2007 Until June 2004, most of effort was on Luneburg Lenses From July 2004, the effort is associated with using Focal Plane Arrays (FPAs) Due for completion in July 2007 2 dishes fitted with Focal Plane Arrays at the Australian candidate SKA site at Mileura in Western Australia (~ 26° 37' S, 117 ° 29.5' E) xNTD (Extended New Technology Demonstrator) Builds upon the designs & deliverables from the NTD Extra funding obtained from CSIRO, 2005 – 2008 We now have the funding, but will not decide if xNTD is technically feasible until Dec 2005, dependent on NTD progress in mitigating the technical risks $25m AUD, 2005 – 2008, 20 dishes with FPAs, at Mileura site A useful telescope in itself But a vision for xNTD to evolve into technology for SKA
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www.atnf.csiro.au SKA Technology Developments at CSIRO Focal Plane Arrays Antennas Digital Processing Receiver Designs Software Systems High-speed networking
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www.atnf.csiro.au Requirements from MNRF Grant Stated aims at 2002 MNRF initiation: To develop multi-beaming antenna technology Advanced optical signal transport Advanced signal processing schemes Developing interference mitigation techniques Integrated into an operating instrument which would benefit the development path towards the SKA Would make use of project deliverables from other MNRF-funded projects eg CABB, MMIC, SKA Siting
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www.atnf.csiro.au Overlap of xNTD and LFD Infrastructure and radio-quiet zone site Complementary frequency ranges Wide field of view science Technology behind the antennas Software Digital Hardware using FPGAs: (reconfigurable design structures) LFD Receiver and NTD Beamformer Correlators Signal Distribution
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www.atnf.csiro.au Establishment of Mileura site for Radio Science in WA Technology, and a range of Radio Science WA Govt support for the Infrastructure WA Govt support for planning controls and negotiations with the traditional owners WA Fellowship in Radio Astronomy is being established CSIRO is collaborating with Curtin Uni on the RF- testing program, and we have further collaboration with UWA/Curtin for xNTD tasks
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www.atnf.csiro.au Summary of Science with xNTD xNTD is ideal for large-area surveys and has good surface brightness sensitivity. It is highly competitive with current/planned instruments New science can be done with the xNTD if the specs / technical challenges can be met. The xNTD is on the pathway to the SKA can add more and more collecting area One-day workshop planned for early 2005 Engage and excite the entire astro community Improve the xNTD science case
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www.atnf.csiro.au xNTD Parameters Area = 4000 m 2 (20 dishes, 180 baselines) Tsys = 50 K Frequency range = 0.8 – 1.8 GHz Bandwidth = 256 MHz Number of independent beams = 48 each beam 1 sq deg 48 sq deg FoV at 1.4 GHz Maximum Baseline < 1000 m Full cross correlation all antennas Located in the RQZ at Mileura, Western Australia ATA - A=10000m 2, FoV=5.5 sq deg, BW=1GHz, Tsys=50K Parkes MB – A=3200m 2, FoV=0.8 sq deg, Tsys=22K ATCA – A=1900m 2, FoV=0.6 sq deg, Tsys=30K Arecibo – A=70000m 2, FoV=0.02 sq deg, Tsys=35K
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www.atnf.csiro.au MNRF Progress to date Original NTD Project Plan Choose NTD concept by 30 June 2004 Choice became one of selecting from Luneburg Lenses Cylinders Focal Plane Arrays Until June 2004, most effort was on Luneburg Lenses From that point on, the effort is on FPAs Revised Preliminary NTD Project Plan 30 September 2004 Present Plan caters for a number of scenarios in an ever-changing environment Now, have decoupled the 2 Project Plans
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www.atnf.csiro.au What difference does the x make? NTD Funded by existing, secured ATNF + MNRF funds 2 interconnected dishes, 15m diameter, each with focal plane array, at proposed SKA site xNTD Additional funding from CSIRO & State Gov 20 dishes, 15 m diameter, arranged in one group, genuine micro-SKA, at proposed SKA site Project Plan: Design & Development Program until Dec 2005 is common for NTD and xNTD xNTD implementation phase from Jan 2006, as a result of sufficient risk mitigation in areas of antenna, FPA, digital beamforming and correlator design
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www.atnf.csiro.au Challenges for xNTD Can we make small steerable dishes cheap enough? Cheap, high performance (wide band and polarization pure) FPAs? Cheap, high performance integrated RXs? No self-generated RFI from RXs (or rejection schemes)? How to transport signals from FPA? DBF (efficient, cost-effective using FPGAs)? Calibration with synthesized varying beam patterns? Correlator (a very large effort) Data storage & transportation Remote operation as a NF from East Coast of Oz?
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www.atnf.csiro.au xNTD Work-break-down Task Groups 1.Antenna - dish and mount 2.Feed System – focal plane array 3.Data Transport – fibre optic 4.Local Oscillator and Control Signalling 5.LNA 6.Receiver 7.FPA Integration 8.Calibration, Control and Monitoring 9.Digital Signal Processing – filterbanks, beamformer, correlator 10.Offline Astronomy Software (actually “post-correlation” software) 11.Wide Area Network – data backhaul, remote observing 12.Site and Infrastructure – Australian SKA site
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www.atnf.csiro.au NTD Antenna System Presently looking at 3 alternatives to meet the challenge of performance/cost The Indian PPD dish design New design using manufacturing techniques available in Australia Refurbishing 2 antennas from Fleurs (for NTD)
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www.atnf.csiro.au Antennas for Extended NTD (xNTD) Proposed project to extend the collecting area of the NTD array to 64m dish equivalent (~ 20 dishes) Based on NTD technology, but will explore options for increased bandwidth (1GHz) and operating band (to 2.4GHz) Shares infrastructure and software development with proposed MIT Mileura Wide-field Array Demonstrator (LFD)
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www.atnf.csiro.au (1) Indian PPD Reflector Prototype Photos from Ken Skinner of SES
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www.atnf.csiro.au (2) Reflector antenna options Custom-built mesh reflector using NC machine tools “High-tech” solution with high accuracy, good repeatability, and no tooling-up costs Local manufacture of prefabricated “flat-pack” reflector; assemble on site Changing the geometry, e.g. offset or larger f / D, no problem Estimated reflector mass significantly < PPD Estimated cost > current PPD estimate
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www.atnf.csiro.au “Flat-pack” Reflector Concept Images & antenna concept from Ross Forsyth
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www.atnf.csiro.au (1) Reflector antenna options Refurbished dishes from the former Fleurs radiotelescope Two 14m dishes in apparently good condition still exist at the Fleurs site (close to Badgery’s Creek, Sydney). Estimated cost of transport + refurbishment ongoing Equatorial mount – advantageous for simple FPA
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www.atnf.csiro.au Fleurs dishes
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www.atnf.csiro.au FPA options Collaborative development of “Vivaldi” array with ASTRON / U.Mass. Best option for short-term demonstrator Tested wideband array technology Limited operating band for SKA Relatively complex manufacture Alternate wideband arrays Looking towards the longer term to SKA Inherently wideband structures Foveated array with “natural” scaling of FoV
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www.atnf.csiro.au FPA system diagram A D PFB A D A D beam- former Router beam- former Array element + integrated analogue receiver Digital receiver Router Beam- former 2 nd stage filterbank To Correlator
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www.atnf.csiro.au Conclusions and next stages of work Initial modelling of reflector + FPA system show that the NTD goals for FoV and operating frequency band are achievable using available technology. Next stages: Collaborative development with e.g. U. Mass. towards prototype NTD FPA Ongoing system optimization study across reflector optical system, FPA, front end & ADC System integration of FPA, analogue and digital electronics: “plumbing”, self RFI, power, thermal, structural, mechanical engineering.
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www.atnf.csiro.au Receiver 200 RXs per dish RF-CMOS chip from MIMIC project (Suzy Jackson) Re-spec’d for NTD/xNTD requirements MIMIC for xNTD, but For NTD: perhaps part of MIMIC chip, and separate backend ICTC doing alternative backup discrete design for early requirements Separate LNA for Tsys requirements (Paul Roberts)
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www.atnf.csiro.au Digital Signal Processing (John Bunton) Each dish produces 200x256x10 6 x2x8 ~ 1 Tera bps Evaluate possibilities for commonality between xNTD/LFD/CABB/ATA requirements Strong collaboration with MIT group; good interchange of ideas between CSIRO and MIT White Paper developed at end of Dec 04 Inter-site extended visits of MIT/CSIRO personnel Buffer, beamformer, correlator NTD ― 2 (not 20) complex beamformers, but one simple buffer/correlator Also, taking wider view, looking at next generation telco technology for the Routing problem.
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www.atnf.csiro.au NTD/SKA Signal Processing Beamformer Needed for first antenna Same for all antennas Correlator Complexity proportional to (no. antennas) 2 Very simple for NTD Comparable to beamformer for xNTD Huge task for the SKA Image formation Currently software only May need hardware accelerators
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www.atnf.csiro.au Beamformer Two polarisations 100 feeds per polarisation Each feed 250 MHz Total data rate 250MHz x 2samples/Hz x 2 pol x 100 feeds About 100 Gsamples/s Beam generated as weighted sum of signals from feeds BUT weighting is frequency dependent Filter signals to get correct weighting Or divide and conquer (filterbank) – narrow band approximation Each feed contributes to ~10 beams Minimum 10 arithmetic operations/sample/beam 100 GSamples/s x 10operation/sample/beam x 10 beams = 10 Tera operations/second !!! Per antenna
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www.atnf.csiro.au Correlator Must form a product between each pair of antennas signals xNTD has 20 antennas x 2 pol = 380 different correlation 48 beams each 250 Mcomplex samples/s 7 operations per correlation 250x7 Moperations/correlation x 380 correlation x 48 beams = 32 Tera operations/sec SKA 250 times as many antennas, twice the bandwidth Task is 125,000 times harder
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www.atnf.csiro.au How FPGAs Have 200 18bit multipliers adder@ 500MHz gives 200 Giga operations/s in a single package (50 per antenna) Development in VHDL – reusable firmware But still need to be smart in how we do the processing otherwise 10 Teraops/s goes to 100 High power autorouters 1000 of pins, route diff pairs for high speed interconnects Without smart design the routing of the data will strangle the design
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www.atnf.csiro.au Possible beamformer
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www.atnf.csiro.au Possible NTD correlator
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www.atnf.csiro.au Reconfigured as MIT correlator
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www.atnf.csiro.au Post-correlation Processing (Tim Cornwell) Not just “off-line” software for xNTD Probably require extensive FPGA-based processing on- line to reduce data enough for storage Commonalities with MIT LFD Resource budget! Anyone aware of case where predicted effort > than actual effort?
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www.atnf.csiro.au The Panorama Mileura means Can see a long way
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www.atnf.csiro.au RFI Mission Characterize RF Spectrum 50MHz-24GHz High Sensitivity Fine Temporal Resolution Fine Frequency Resolution All directions Both orthogonal polarizations. Noise source calibration Period 1 year. ~Terabyte of data Demonstrate application of Solar power. Collaborate with WA Govt and Curtin Uni.
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www.atnf.csiro.au RFI Measurements are under way
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www.atnf.csiro.au RFI Measurements (2)
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www.atnf.csiro.au NTD/xNTD Project Strategy
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