technical foundations & enabling technologies – ds4
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Technical Foundations & Enabling Technologies – DS4. Andrew Faulkner. Remit:. Technical foundations and Enabling Technologies. The Demonstrator is: 2-PAD. Overall. DS4 very broad range with many institutions involved - PowerPoint PPT PresentationTRANSCRIPT
Technical Foundations &Technical Foundations &Enabling Technologies – Enabling Technologies – DS4DS4
Andrew Faulkner
April 22, 2023 SKADS Workshop 2006 Andrew Faulkner 2
Remit:Remit:
Technical foundations and
Enabling Technologies
The Demonstrator is:
2-PAD2-PAD
April 22, 2023 SKADS Workshop 2006 Andrew Faulkner 3
OverallOverall
• DS4 very broad range with many institutions involved
• Schedule is disrupted – particularly in UK – due to funding
delays (funds now awarded)
• We will deliver by June 2009
There are 3 more years......
April 22, 2023 SKADS Workshop 2006 Andrew Faulkner 4
DS4 work scheduleDS4 work schedule
2006 Investigate and consider any possible approach. Blue Sky etc...
2007-Q1 Select 2 or 3 of the most likely approaches
2007 Prototyping and developing phase. Build models, bring together systems
2008-Q1 Select 2-PAD components and finalise2-PAD designnote: individual subsystem work will continue
2008 Build 2-PAD
2009-1H Test 2-PAD and write reportReport on advances in subsystem research
April 22, 2023 SKADS Workshop 2006 Andrew Faulkner 5
RisksRisks
Low Risk: the components exist, but can be improved....– Antenna array, needs performance and cost and ease
improvement – LNA, the system noise and the cost need to be improved– Processing, currently far to little capacity, but will work at some
limited bandwidth
High Risk: does not exist...– Low power, low cost high speed ADC– Cheap enough analog links – must be <€5 each– RFI mitigation - unproven
April 22, 2023 SKADS Workshop 2006 Andrew Faulkner 6
We need information from Site surveys
BitsBits
• Digitisation is not to do with instrument dynamic range!• It is to do with the RFI environment.• To make a practical all-digital aperture array must use
minimal digitisation e.g. 4-bits
CANNOTCANNOT design for a European environment!!
First cut suggests that 4-bits is OK...(phew!)
April 22, 2023 SKADS Workshop 2006 Andrew Faulkner 7
2-PAD System2-PAD System
• Consider Station level AA with 2-PAD2-PAD as a subsystem– Hence understand scaling and processing issues
• Distances, cooling, power etc
– Station wide construction requirements– Reliability analysis (system layout vital)
• Important to have benchmark specification!– Building first modelBuilding first model
• Focus on the bottlenecks– Possibility/availability of components
– CostCost
April 22, 2023 SKADS Workshop 2006 Andrew Faulkner 8
Possible Station - Side viewPossible Station - Side view
April 22, 2023 SKADS Workshop 2006 Andrew Faulkner 9
Desert
Station Proc. Local P.
FOV processing+ ¼ tile processing10m x 5m
FOV processing+ ¼ tile processing10m x 5m x 2.5m
Cooling systemUsing heat transfer ground
Optical fibredigital links
Tile processingfor ¼ of array5m x 5m x 2.5m
Array supportsproviding ~1.6m headroom
Inflation pumpEntrance
Element array50m x 50m
Short range analogue links from elements to local processing
Array physical support grid
Inflatable Ray dome
Possible Station - Side viewPossible Station - Side view
To scale
April 22, 2023 SKADS Workshop 2006 Andrew Faulkner 10
LocalProc.
LocalProc.
StationProcessing
LocalProc.
Matrix of supports~2m spacing (625)
Inflatable Ray dome
Entrance
Inflationpump
Element array50m x 50m
Tile processingfor ¼ of array5m x 5m
Optical fibredigital links
Wide area fibre link to Correlator
FOV processing+ ¼ tile processing10m x 5m
Short range analogue linksfrom elementsto local proc(only ¼ shown)
StationStationLayoutLayout(looking up)(looking up)
April 22, 2023 SKADS Workshop 2006 Andrew Faulkner 11
Tile Receiving elementsTile Receiving elements
LNA
Antenna
Filter+
DifferentialLine driver
Vert. Pol. Horiz. Pol.
Low cost screened twisted pair 20m max
Processing centre
+veReg Reg
IndividualPCB
April 22, 2023 SKADS Workshop 2006 Andrew Faulkner 12
‘‘Tile’ configurationTile’ configuration element receiver
=
Analogue twisted pair to Processing Centre
0 1 2 3 4 5 6 7 12 13 14 15 01234567
12131415
Notes:• 16 elements / side• Groups of 16 Rx in a cluster (4x4)• Overall size: 3.0m square 9.0m2
• 512 links / tile (2x16x16)
4x4 receiver units
……
…
………………
…
……
… … … … … … … … …… … …
April 22, 2023 SKADS Workshop 2006 Andrew Faulkner 13
Overall StationOverall Station
Bunkers
…..
…..
..
..
..
16 x 16 array of Tiles ~2300 m2
256 Tile processors
FOV1
256 x 256 1GHz Analog links
FOV2
FOV8
…..
8 (say) FOV
processors
TP1TP2TP3
TP17TP18TP19
TP254TP255TP256
…..
.
256 x 85-10Gb Optical
fibres
1GHz signalsFrom each element
600MHz BWFOVs; 8 per tile
32 off40Gb Optical
fibres per FOV polarisation
To Correlator
256 beams of 600MHz BW
per FOV
Assumes 4-bit samples
April 22, 2023 SKADS Workshop 2006 Andrew Faulkner 14
Final Thoughts....Final Thoughts....
• Cost dominated by array and analogue links
• Total power requirements vital
• Power and cost of ADC an issue
• Communications for the internal data streams
• Continue system design:– Frequency dependant aperture
– Calibration approaches
– Independent many small beams over whole scan angle
– Flexibility on beams/bandwidth/sampling for Tx to correlator
On SKA timescales: a digital AAAA appears:
possible, practical and cost effective