Feb 2005

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

Mileura Site

Mileura, Pathway to SKA 150km Perth 850km Geraldton ~500km

What is Planned for Mileura?  Mileura Widefield Array  NTD/xNTD (CSIRO led) ― towards Australia’s SKA  LFD (MIT Haystack led) ― Aperture Array MHz  Berkeley Array ― EOR experiment  CSIRO (Ron Ekers et al) ― for EOR  RQZ ― essential for all of the above

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 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

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

SKA Technology Developments at CSIRO  Focal Plane Arrays  Antennas  Digital Processing  Receiver Designs  Software Systems  High-speed networking

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

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

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

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

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

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

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

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?

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

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)

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)

(1) Indian PPD Reflector Prototype Photos from Ken Skinner of SES

(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

“Flat-pack” Reflector Concept Images & antenna concept from Ross Forsyth

(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

Fleurs dishes

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

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

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.

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)

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.

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

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

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

How  FPGAs  Have bit multipliers 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

Possible beamformer

Possible NTD correlator

Reconfigured as MIT correlator

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?

The Panorama Mileura means Can see a long way

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.

RFI Measurements are under way

RFI Measurements (2)

NTD/xNTD Project Strategy