Transcript Aperture Array Verification Programme

AAVS1/2-low demonstrators
Jan Geralt Bij de Vaate
Dec 2010 AAVP Cambridge workshop
AAVP
SKA1: AA-low
station
Cooling
2-Pol
Elements
...
Element Digitisation
Copper
Fibre
...
Element
Station Processing
C&M
...
......
......
Digitisation
Tile
Tile
Digitisation
RFIDigitisation
Shielded
......
Clock
2x 500MHz
Analogue
+ power
Element Digitisation
Front-end
...
Each station:
Diameter:
180m
# of elements: 11,300
Element
Copper workshop
Dec 2010 links:
AAVP Cambridge
Station
Beams
Element Data
Power Distribution
AAVP
RFI shielded
Control &
Monitoring
System
clock
To
Correlator
&
Services
Power
Grid
Proposed specification
• From draft SKA phase 1 system description, June 2010
Dec 2010 AAVP Cambridge workshop
AAVP
After the 50MHz issue..
• And LOFAR / MWA /..
• AAVS-low needs to address
– Broadband Aeff / Tsys (antenna, lna, beamforming)
– Broadband receiver
– Cost effective signal processing
– Calibration
– Monitoring & Control
• Some specs need new developments
• Some (just) need proper choices
– Note: one array for 50-450MHz not possible
Dec 2010 AAVP Cambridge workshop
AAVP
AA-low antenna design
• Addressed by
– UCAM
– INAF / IEIIT-CNR
– ICRAR
– ASTRON (2011)
Razavi 2010
Wijnholds 2010
• ~10 full scale antenna prototypes build 2011
• Action
– Agree on test approach/range
– Extend analyses for scan angle and frequency
Dec 2010 AAVP Cambridge workshop
AAVP
AA-low station
• Addressed by
– UCAM
– UMAN
– 2011..ICRAR, ASTRON
• Many options
Ap
1.5 km2
0.84 km2
0.5
Freq
Tsys
Ae8/Ts
Ae16/Ts
Ae3
MHz
K
m2 K-1
m2 K-1
m2
43
9400
160
90
60
4000
375
210
1
85*
1600
940*
525
3
120*
700
1070
1200*
8
170*
320
1170
1310
18
240*
160
1310
18
340
85
480
60
17
Bregman 2010
• Action
– Form (small) focussed team
– AAVP, SPDO domain spec and scientist , ‘AA’ astronomer
Dec 2010 AAVP Cambridge workshop
AAVP
Some trade offs
Deployment Freq
cost
bandwidth
Aeff /Tsys
Dynamic range
Random elements
High
Good
Optimal
Optimal
Random tiles
Moderate
Good
Good
Good
Regular grid tiles
Low
Optimal
Good
(strong gratings)
-LOFAR, MWA, AAVP will need to confirm/complete the trade-offs
-More: Filling factor, uv coverage, calibration, FoV etc..
Dec 2010 AAVP Cambridge workshop
AAVP
AA-low LNA
• Addressed by
– INAF
– ICRAR
– UMAN
• Should not be an issue but
– Coupling
– Impedance, 50, 150, 300 Ohm
– Differential
LOFAR simulation, Kant
Dec 2010 AAVP Cambridge workshop
AAVP
AA-low receiver
• 6, 8 or 12 bits needed
– 8 fine?
• SPDO: please release new RFI data!
• RFI at 55MHz (not in this plot)
– Levels??
– 50-70MHz does not come for free
CoDR docs
• Action
– Requirements analyses: ASTRON+SPDO
Dec 2010 AAVP Cambridge workshop
AAVP
AA-low costing
• Analogies costing
– LOFAR
– MWA
• AA station model input by AAVP PE and AA domain
specialist
Dec 2010 AAVP Cambridge workshop
AAVP
AAVS rationale
• Prototyping essential
• LOFAR initial test station and CS1, MWA 32T
– Antenna array needs adequate receivers and back-end
– Test software
• Common test platform needed!
– For AA-low options & AA-mid
– Site: Sufficient low RFI, fibre link, power,
– Signal processing (limited bandwidth?)
• Action
– Define requirements test platform
Dec 2010 AAVP Cambridge workshop
AAVP
AAVS1: AA-low
• Demonstrate electromagnetic and front end performance
– Sufficient collecting area (250-500m2?), possibly two versions
– Focus on broadband antenna and front-end design
– Evaluation using existing processing
• UNIBOARD, ROACH or LOFAR / MWA
– Goal: establish antenna, tile and station configuration
• Extensive station simulations required
– Critical Design Review
31-12-2011
– Commissioning
31-12-2012
– Reporting
30-6-2013
Dec 2010 AAVP Cambridge workshop
AAVP
AAVS1: AA-low
• Actions
– Specify AAVS1
– Based on SKA1 System Requirement Specification
– Hardware costs / resources
Inst. Bandwidth
70 – 450 MHz
380MHz
System Temp
Array Type
120K
Sparse
Scan angle
Polarisations
Tile size
No. of Tiles
±45°
2 linear
64
4
AA-lo
Overlap with AA-hi to provide even sensitivity
Combine both polarisations onto one
processing channel
At 300 MHz, Sky noise 50K, Trec 70K
Increases Aeff at low frequency to part
counter Sky noise
Dual polarisation elements
AAVP DoW March 2010, to be updated
Dec 2010 AAVP Cambridge workshop
AAVP
AAVS2: AA-low
• Pre production phase:
– Preparing for mass-production, design for manufacturing
• AAVS2 prototype
– Test tooled production components
– SKA1 performance compliance
– Bandwidth, Tsys, stability, signal processing, calibratability, climate
– Critical Design Review
30-9-2013
– Construction
2014
– Comisioning
2015
– Reporting for SKA1 PR
31-12-2015
Dec 2010 AAVP Cambridge workshop
AAVP
AAVS2 requirements
• In order to ramp-up production in 2016, AAVS2 should be
sufficiently large: e.g. 1-2% SKA1 (~10.000 elements)
• Built with SKA1 tooling
• A couple of ‘d’ diameter stations
including digital station beamforming
– Note: e.g. if used UNIBOARD 2 needs to production ready by 2014
• On the SKA site
• Acceptance tests of this station should be considered in
absence of correlator
Schedule is tight: custom MMICs, photonic links,
signal processing boards
Dec 2010 AAVP Cambridge workshop
AAVP
AA-low
• Montly telecons
• Wiki for progress docs, minutes etc.
– www.ska-aavp.eu/aavpwiki
• Workpackages
– System design
– Antenna element, array
– Front-end (LNA, receiver, data link)
– Calibration & beamforming
– Proto type, Design, Construction & commisioning, Evaluation
Dec 2010 AAVP Cambridge workshop
AAVP