Goals of DVA-1 Meeting
• Overall goal: build an SKA antenna with SKA
feeds/receivers, verify performance and fabrication/costs for
the next stages of the SKA
• Project description and definition
– purpose and scope
– cost
– schedule
• Partnership
– resources (in-kind, cash)
• Management
– as in MoU draft?
• Technical decisions
• Program/project decisions
15-16 April 2010
DVA1 Meeting at NSF
1
Technical Decisions
•
•
•
•
•
•
Required technical specifications
Aperture size (12m – 15m)
Optics (offset gregorian): shaping?
Backup structure: spars, shell
Pedestal type
Feed and receiver plan
– SPFs
– PAFs
– Indexer
15-16 April 2010
DVA1 Meeting at NSF
2
Program/Project Decisions
• Management plan and MoU/LoI
• Schedule
– milestones (TDP, PrepSKA, SKA program)
– deliverables (hardware  test results, reports)
• Site
– which facility and where on site?
• Testing program
– single dish tests:
• those necessary for the costed system by end-2012
• those needed for antennas program leading to the Phase-I dish array
– interferometric tests not within timeline/scope of end-2012
project
15-16 April 2010
DVA1 Meeting at NSF
3
Scope of the DVA-1 Project
• The first in a series of converging prototypes that will
optimize performance at minimum cost (e.g. A/T per dollar +
imaging performance)
• A primary deliverable of the US SKA TDP
– optimized antenna + feeds for SKA-mid
– WBSPFs and PAFs accommodated
• A global project but centered in North America
• Delivered to the project by end of 2012 (including testing)
• Current plan (to be agreed on):
– fabrication, integration and testing at EVLA site by end of 2012 to
provide input to the costed system design
– single-dish tests with suite of feeds
– extended testing program as needed for lead-up to Phase-I
construction (with post-TDP, post-PrepSKA funding)
15-16 April 2010
DVA1 Meeting at NSF
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Overall Context in TDP
• System cost
• Costs that scale with N (antennas, feeds)
• Processing costs that scale as N2 x number of beams
• Maximize A/T per antenna in a low-cost design
• minimizes number of antennas needed for total A/T
• also maximizes survey speed via the (A/T)2 factor
• Target high imaging dynamic range and minimum
susceptibility to RFI (clear aperture)
• Demonstrate imaging capability through simulation
by Calibration and Processing Group et al. using as
input measurements on DVA-1
15-16 April 2010
DVA1 Meeting at NSF
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Basic specifications
•
•
•
•
•
Offset Gregorian optics
Frequency range: 0.3 to 10 GHz (1 to 10 GHz)
Aperture efficiency: >60% above 1 GHz
Antenna noise temperature <10K
Pointing stability: <1% gain variation @half-power point
at 1.4 GHz
• Minimum 30 year lifetime
• Minimum 1 year maintenance interval (target 5 year)
• Design to be as close as possible to the final SKA dish
design
– Assessment of real performance
– Good cost estimate
15-16 April 2010
DVA1 Meeting at NSF
6
Optical design of reflectors
Working plan:
• Dual shaped, offset reflectors with a Gregorian subreflector.
• Subreflector opening angle chosen to accommodate wide band
feed(s).
• Shaped optics having very low spillover and high aperture
efficiency to maximize A/T in a design intended to minimize
costs
• Usage of available real estate for multiple feeds and a PAF;
DVA-1 will include a feed indexer
15-16 April 2010
DVA1 Meeting at NSF
7
Reflector design options
Dual shell reflector and
support, composites
Single composite shell and
sparse support framing
15-16 April 2010
DVA1 Meeting at NSF
8
Feed Options to Cover 0.3 to 10 GHz (nominal)
15-16 April 2010
DVA1 Meeting at NSF
9
Canadian CART
program + TDP Work
by Matt Fleming:
15-16 April 2010
DVA1 Meeting at NSF
10
Issues and Decisions
• Diameter: 15m nominal (12m still possible as a choice)
• Optical design: offset Gregorian optics
– rationale for shaped optics in TDP Memo (in prep)
– final choice depends on assessment of imaging performance and
long-term flexibility as well as optimized A/T @ minimum cost
• Fabrication material
– dual-shell composite vs composite + metal spar structure
– (segmented metal is a possible parallel approach)
• Full suite of TDP-developed feed antennas that cover 0.3 to
10 GHz
– various combinations of WBSPFs and octave feeds
– antenna will accommodate a PAF when appropriate
• Feed indexer included in design with deployment at
appropriate phase of testing
15-16 April 2010
DVA1 Meeting at NSF
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•
Developing
DVA-1
Partnership
Cornell/TDP
–
–
Optical design: Baker, Cortes, Imbriale (JPL)
WBSPFs:
•
•
•
–
–
•
N. Roddis and P. Dewdney
NRAO
–
•
•
•
•
G. Lacy (mechanical, composites)
G. Hovey
S. Dougherty
SPDO
–
•
Mechanical design: Fleming (Minex)
Calibration and Processing: Kemball (UIUC) et al
DRAO (CART program for composite reflector)
–
–
–
•
Cortes (Cornell)
Weinreb (Caltech)
Welch (UCB)
Project management and integration with EVLA
Australia/CASS
China/JLRAT
South Africa/MeerKAT
Testing:
–
–
single dish tests by TDP team + other partners
array tests: in 2012+ post-preparatory/engineering design phase
15-16 April 2010
DVA1 Meeting at NSF
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Management of DVA-1
To be agreed upon:
• Project Manager
• Project Engineer
• Collaboration Board (Cornell, DRAO, NRAO,
SPDO, …)
– determined by groups that sign on to the project
• DVA-1 design reviews
– coordinated with (but separate from) SPDO design
reviews
15-16 April 2010
DVA1 Meeting at NSF
13
DVA Context
&
DVP Goals
P. Dewdney
Apr 15, 2010
System Hierarchy (Part 1)
SPDO
SKA User
System
Telescope
Dish
Cryo
WBSPF
Feed
Receptors
PAF
Receivers
LNA
Feed
elements
Beamformer
LNA
To
Figure
B
People
Sparse AA
Array
(Low)
DVP
Dish
Array
L7
User System
Sparse AA
Array
(High)
Beam
management
Receptors
Feed
elements
LNA
Beamformer
L6
System
L5
Elements
Dense AA
Array
Beam
management
Receptors
Feed
elements
Beam
former
L4
Sub systems
Beam
management
L3
Assemblies
LNA
L2
Sub-assemblies
L1
Components
L0
Parts
16
System Hierarchy (Part 2)
SPDO
L7
User System
From
Figure
A
Facilities
Signal
Proc
Channeliser
and
Correlator
Non
visibility
processor
Grid
STaN
Core
site
Backup
Computing
and Software
Central
site
Alternative
Power
Outlying
stations
Antenna
foundations
Core
site
Infrastructure
Central
site
Trenches
Core
site
Outlying
stations
Roads
Water
Support
Fences
Signal
Processing
Facility
L6
System
Central
site
Visitor
centre
Stores
Off
site
Support
Support
Workshops
Offices
L5
Elements
Regional
Centres
HQ
Operations and
Maintenance
Centre(s)
L4
Sub systems
Regional
Engineering
Centres
L3
Assemblies
L2
Sub-assemblies
L1
Components
L0
Parts
17
Dish Verification Program (DVP)
SPDO
•
Process to verify performance of dishes for the Dish
Array in the System Hierarchy.
– Element level.
•
Dishes equipped with well defined interfaces to other
system elements:
–
–
–
–
•
Power
Signal transport
Monitor and Control
Other infrastructure
Verified to be capable of handling all feeds and
receivers needed to carry out the dish-based science.
– May not be so-equipped at initial roll-out.
18
DVP Goals
•
Risk reduction
SPDO
– When built up into the SKA system, show that dishes will meet all the
science requirements;
– Also meet all other requirements needed to integrate into a system and
operate in the field.
•
Design, produce and test one or more SKA antennas;
– with the greatest system sensitivity (Ae/Tsys and/or Survey Speed) per
unit system cost (total cost of ownership);
– As well as possible, ensure that the contribution of antenna-related
systematic errors is within acceptable limits;
– Designs/testing programs converging to a detailed design that is
manufacturable in production quantities.
•
•
Understand the costs.
Converge to a production-ready, documented antenna
19
design (production data-pack).
Integrated Approach
SPDO
SKA Science Case
DRM
SYSTEM
Tradeoffs
Concept Phase
System Definition Phase
DRM Analysis
Requirements
Development
Analysis
Validation
High level
requirements
Memo 100
Concepts
System Prelim Design Phase
C
O
D
R
Design
Functional analysis, verification and synthesis
Design verification
S
R
R
P
D
R
Technologies
Risk
Management
Plan
Selections for reference design
Risks
ELEMENTS
Concept Phase
Concepts
DVAs
Tradeoffs
Definition Phase
C
O
D
R
Requirements (Development, Analysis , Validation)
Prelim Design Phase
S
R
R
P
D
R
Design (Functional analysis, verification and synthesis, Design verification)
Risk mitigation strategies and projects
Verification programmes (DVP, AAVP, other domains), Design studies, Precursors, Pathfinders
Risks
RISK MANAGEMENT
20
Time Scale
SPDO
2009
2010
2011
2012
2013
2014
2015
2016
Detailed Design, Prod. Eng
& Tooling
SKA Preparatory Phase
2017
2018
Phase 1 Construction, Verification, Commissioning, Acceptance,
Integration & First Science
Phase 2 …..
REV
Science
REV
REV
REV
Science / Engineering tradeoffs
DRM Development
Phase 2 Science Development
Revision of Science Case
Early Science Proposals
Refinement of Early Science
REV
CoDR
PDR
SRR
System
Engineering
Definition and Design
CoDR
Dishes
Concept Definition AAs
AAVS2 development and testing
PDR
CDR
Preliminary
Design
SRR
Factory Assembly, Integration and Testing
Purchase or
Fabrication
PDR
Sub-System Definition
CDR
Preliminary Design
Data Storage
Phase 2 Continuation
PR
Factory Assembly, Integration and Testing
Site Assembly, Integration and Testing
Detailed Design
Phase 2 Correlator Design
Temporary Software Correlator
SRR
Software Requirements Definition
Preliminary high level architecture
Phase 2 Continuation
Phase 2 Continuation
Site Assembly, Integration and Testing
Pulsar and Transient Processor
Monitoring & Control
Phase 2 Continuation
AAVS2 demo
Hardware Correlator Early Fabrication
Beamformer and Correlator
Imaging Concept
Factory Assembly, Integration and Testing
PR
Detailed
Design
Front End and Channeliser
CoDR
Software &
Computing
Review dates are
preliminary.
PR
Tooling and Early
Fabrication
CDR
Prototype AAVS1
Testing
Sub-System Definition
CoDR
Signal
Processing
PDR
SRR
Concept definition
CDR
DVA2 development and testing
Site Assembly, Integration and Testing
AA Prototype
Fabrication
CoDR
Signal transport
& Networks
Phase 1 Verification and Commisioning
Continuous Performance Evaluation
DVA1
Prototype Dish Testing
SRR
AA Sub-Sys.
Definition
Phase 1 Systems integration
Phase 1 System Testing
Continued System Engineering for Phase 2
PDR
SRR
CoDR
Aperture
Arrays
CDR
System refinement, change management
DVP
DVA1
Dish Prototype
Fabrication
Dish Sub-Sys.
Definition
Concept Definition
Dishes, AAs
Shared Risk Science Operations
REV
PDR
Refine high level architecture
Preliminary Design
CDR
Detailed Design, Coding, Integration with platforms
and testing
Phase 1 Refinement and Roll-out
On-site Testing
S/W Development & Roll-out for Phase 2
PDR
RFI Monitoring
RQZ
Site characteristics
Atmospheric studies
Configuration studies
Continued RFI and Tropo Monitoring
Remote Station Land Acquisition &
Environmental Studies
report
Site
Engineering
CDR
CDR
Central Data Processing Facility
Site Acceptance tests including RFI qualification
Science Computing Facility
Infrastructure Detailed Design (fibre & power)
Infrastructure Detailed
Design (buildings)
Phase 2
Continuation
Ops and Maintenance Facility
Antenna Foundations and Trenching Roll out
CoDR
Project
management
PrepSKA
Plan
SKA Scope definition
WBS, resource allocation
PDR
CDR
PM Plan
&
Schedule
Final SKA Deployment Plan
Project execution, monitor and control
Project staffing & development
Milestones
Baseline design
for Phase 1
Rev 7a
2010-04-13
2009
2010
2011
Phase 1
construction
approval
Costed
system design
Site decision
2012
2013
Start of Phase 1
Construction
2014
2015
Baseline design for
Phase 2
2016
2017
Start of
Phase 2
Construction
2018
21
Time Scale
SPDO
2009
2010
2011
2012
2013
SKA Preparatory Phase
CoDR
Dishes
Concept
Definition
PDR
SRR
Dish Sub-Sys.
Definition
DVA1 Prototype
Fabrication
2014
2015
2016
Detailed Design, Prod. Eng
& Tooling
DVA1
Prototype Testing
Phase 1
Construction
CDR
DVA2 development and testing
PR
Tooling and Early
Fabrication
Milestones
Baseline design
for Phase 1
Rev 7a
2010-04-13
2009
2010
2011
Phase 1
construction
approval
Costed
system design
Site decision
2012
2013
Start of Phase 1
Construction
2014
2015
2016
Review dates are
preliminary.
22
End
23
Extra
15-16 April 2010
DVA1 Meeting at NSF
24
Verifying dish performance
• Antenna and feed
design parameters:
– Mount type
– Reflector:
• Overall system performance
verification:
– Cost per unit achieved
sensitivity as a function of:
• Angular distance from center
of main lobe: ρ
• Polarization: {I,Q,U,V}
• Frequency: ω
• Size, shape, and
manufacturing method
–
–
–
–
–
Optics
Feed and illumination
Polarization purity
Net bandwidth
Etc.
• Measurements on
DVA-1
15-16 April 2010
– Feasibility:
• Limiting sensitivity in
{I,Q,U,V} (ρ ,ω) due to
uncorrected systematic errors.
• Assessment of antenna
performance vis a vis
science requirements (end
to end simulations)
DVA1 Meeting at NSF
15-16 April 2010
DVA1 Meeting at NSF
26
• Optical design of reflectors.
Dual shaped, offset reflectors with a Gregorian subreflector.
Subreflector opening angle chosen to accommodate wide band feed(s).
Shaped optics having very low spillover and high aperture efficiency.
Incorporation of “real estate” for multiple feeds and a PAF.
•
Light weight, optimized mechanical design
Utilization of single shell reflectors as integral structural members.
Inclusion of a feed indexer to mount multiple feeds.
Design for low cost in mass production.
•
Mount and test multiple feeds and receivers.
Optics designed to accommodate feeds of intermediate gain which achieves a practical primary reflector size.
•
Basic specifications:
Frequency range: .3 to 10 GHz.
Aperture efficiency: >60%
Antenna noise temperature <10K
Pointing stability: <1% gain variation @ ½ power point (1.4 GHz.)
Minimum 30 year lifetime
Minimum 1 year maintenance interval (target 5 year)
•
15-16 April 2010
DVA1 Meeting at NSF
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15-16 April 2010
DVA1 Meeting at NSF
28
Meeting Motivations and Outcomes
•
•
•
•
NSF review of TDP and DVA plan forthcoming
Overall timelines for SKA, TDP and PrepSKA
Readiness for convergence in D&D
Parallel development plan for SKA antennas
– DVA-1, DVA-2 …
– Large volume manufacturing options and costs
• conventional, composites, hydroforming
• SKA project decision tree over next 5yr
– tradeoffs between science, costs and schedule
15-16 April 2010
DVA1 Meeting at NSF
29
DVA-1 Project Book
•
Purpose of DVA-1
–
•
•
Relationship to DVA-2
How it fits into overall DVP activity
Technical description
•
•
•
•
•
•
•
•
Test site (and reflector fab)
Testing plan and elements
•
•
•
•
•
Reflectors
Backup structure
Pedestal
Indexer
Feeds and receivers
Interface to EVLA network and correlator
single-dish tests
array tests
Decommissioning of DVA-1
Detailed schedule
Management
•
•
•
Organizations, Personnel and Org chart
Funding and funding profile
MoA or MoU?
15-16 April 2010
DVA1 Meeting at NSF
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