Add Title here - Square Kilometre Array
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Transcript Add Title here - Square Kilometre Array
Feb 2005
Overview of Australia’s NTD/SKA
Activities for Mileura in WA
For SKADS Meeting, Amsterdam, 24 February 2005
Presented by: Colin Jacka and John O’Sullivan
24 February 2005
Mileura Site
www.atnf.csiro.au
Mileura, Pathway to SKA
www.atnf.csiro.au
Perth 850km
Geraldton ~500km
150km
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
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
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
www.atnf.csiro.au
SKA Technology Developments at CSIRO
Focal Plane Arrays
Antennas
Digital Processing
Receiver Designs
Software Systems
High-speed networking
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
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
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 RFtesting program, and we have further collaboration
with UWA/Curtin for xNTD tasks
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
www.atnf.csiro.au
xNTD Parameters
www.atnf.csiro.au
Area = 4000 m2 (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=10000m2, FoV=5.5 sq deg, BW=1GHz, Tsys=50K
Parkes MB – A=3200m2, FoV=0.8 sq deg, Tsys=22K
ATCA – A=1900m2, FoV=0.6 sq deg, Tsys=30K
Arecibo – A=70000m2, 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
www.atnf.csiro.au
What difference does the x make?
www.atnf.csiro.au
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?
www.atnf.csiro.au
xNTD Work-break-down Task Groups
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
Antenna - dish and mount
Feed System – focal plane array
Data Transport – fibre optic
Local Oscillator and Control Signalling
LNA
Receiver
FPA Integration
Calibration, Control and Monitoring
Digital Signal Processing – filterbanks, beamformer, correlator
Offline Astronomy Software (actually “post-correlation” software)
Wide Area Network – data backhaul, remote observing
Site and Infrastructure – Australian SKA site
www.atnf.csiro.au
NTD Antenna System
www.atnf.csiro.au
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)
www.atnf.csiro.au
(1) Indian PPD Reflector Prototype
Photos from Ken Skinner of SES
www.atnf.csiro.au
(2) Reflector antenna options
www.atnf.csiro.au
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
www.atnf.csiro.au
(1) Reflector antenna options
www.atnf.csiro.au
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
www.atnf.csiro.au
FPA options
www.atnf.csiro.au
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
www.atnf.csiro.au
A
A
Array element +
integrated analogue
receiver
PFB
D
PFB
D
PFB
Digital receiver
beamformer
PFB
Router
A
D
To
Correlator
beamformer
Router
Beamformer
PFB
2nd stage
filterbank
Conclusions and next stages of work
www.atnf.csiro.au
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
www.atnf.csiro.au
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 200x256x106x2x8 ~ 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.
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
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
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
www.atnf.csiro.au
How
www.atnf.csiro.au
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
Possible beamformer
~512 MS/s Real or
~256 MS/s Complex
16 channel
Polyphase
Output 16x16MHz
complex
Inputs from
100 Vivaldi
feeds
~512 MS/s Real or
~256 MS/s Complex
16 channel
Polyphase
Output 16x16MHz
complex
www.atnf.csiro.au
Beamformer
~48 beam
16 MHz
48 16MHz
1k Channel
Polyphase
Routing
network
Outputs
16MHz
all feeds
Beamformer
~48 beam
16 MHz
48 16MHz
1k Channel
Polyphase
48 beams
256 MS/s
(4R,4I) complex
100 Gbits/s
to central
correlator and
beamformer
Possible NTD correlator
Dual Rocket
I/O Links
2x8 Gb/s
8 antenna
2 beam
Router and
Buffer
www.atnf.csiro.au
Correlator Board
Beam 1 HF
Router and data
serialiser
XC4VFX20
HF Correlator
Beam 1
2 x XC4VSX35
DDR2
DDR2
LTA
XC4VLX25
8 antenna
2 beam
Router and
Buffer
Beam 1 LF
Router and data
serialiser
XC4VFX20
LF Correlator
Beam 1
2 x XC4VSX35
Beam 2 HF
Router and data
serialiser
XC4VFX20
HF Correlator
Beam 2
2 x XC4VSX35
DDR2
DDR2
DDR2
LTA
XC4VLX25
8 antenna
2 beam
Router and
Buffer
Beam 2 LF
Router and data
serialiser
XC4VFX20
LF Correlator
Beam 2
2 x XC4VSX35
DDR2
Reconfigured as MIT correlator
8 stations
16 tiles
Router and
Buffer
Dual Rocket
I/O Links
2x8 Gb/s
www.atnf.csiro.au
9 Rocket I/O
outputs
0.888MHz
Intermediate
Router
8 MHz 512
3 x XC4VFX20
(one of four)
8 stations
16 tiles
Router and
Buffer
512 antennas
Correlator Board (one of 9 per Intermediate Router)
8 stations
16 tiles
Router and
Buffer
Router and data
serialiser
XC4VFX20
HF Correlator
Beam 1
2 x XC4VSX35
DDR2
DDR2
LTA
XC4VLX25
8 stations
16 tiles
Router and
Buffer
Router and data
serialiser
XC4VFX20
LF Correlator
Beam 1
2 x XC4VSX35
DDR2
256 antennas to routers 2&3
Router and data
serialiser
XC4VFX20
HF Correlator
Beam 2
2 x XC4VSX35
DDR2
DDR2
LTA
XC4VLX25
384 antennas
Router and data
serialiser
XC4VFX20
LF Correlator
Beam 2
2 x XC4VSX35
DDR2
Post-correlation Processing
(Tim Cornwell)
Not just “off-line” software for xNTD
Probably require extensive FPGA-based processing online to reduce data enough for storage
Commonalities with MIT LFD
Resource budget!
Anyone aware of case where
predicted effort > than actual effort?
www.atnf.csiro.au
The Panorama
www.atnf.csiro.au
Mileura means Can see a long way
RFI Mission
www.atnf.csiro.au
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
www.atnf.csiro.au
RFI Measurements (2)
www.atnf.csiro.au
NTD/xNTD Project Strategy
www.atnf.csiro.au