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Goals of DVA-1 Meeting

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

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Goals of DVA-1 Meeting

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  1. 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 DVA1 Meeting at NSF

  2. 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 DVA1 Meeting at NSF

  3. 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 DVA1 Meeting at NSF

  4. 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) DVA1 Meeting at NSF

  5. 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 DVA1 Meeting at NSF

  6. 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 DVA1 Meeting at NSF

  7. 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 DVA1 Meeting at NSF

  8. Reflector design options Dual shell reflector and support, composites Single composite shell and sparse support framing DVA1 Meeting at NSF

  9. Feed Options to Cover 0.3 to 10 GHz (nominal) DVA1 Meeting at NSF

  10. Canadian CART program + TDP Work by Matt Fleming: DVA1 Meeting at NSF

  11. 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 DVA1 Meeting at NSF

  12. Developing DVA-1 Partnership • Cornell/TDP • Optical design: Baker, Cortes, Imbriale (JPL) • WBSPFs: • Cortes (Cornell) • Weinreb (Caltech) • Welch (UCB) • Mechanical design: Fleming (Minex) • Calibration and Processing: Kemball (UIUC) et al • DRAO (CART program for composite reflector) • G. Lacy (mechanical, composites) • G. Hovey • S. Dougherty • SPDO • N. Roddis and P. Dewdney • NRAO • 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 DVA1 Meeting at NSF

  13. 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 DVA1 Meeting at NSF

  14. DVA Context& DVP GoalsP. DewdneyApr 15, 2010

  15. System Hierarchy (Part 1) DVP

  16. System Hierarchy (Part 2)

  17. Dish Verification Program (DVP) • 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 • 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 design (production data-pack).

  19. Integrated Approach DVAs

  20. Time Scale Review dates are preliminary.

  21. Time Scale Review dates are preliminary.

  22. End

  23. Extra DVA1 Meeting at NSF

  24. Verifying dish performance • Antenna and feed design parameters: • Mount type • Reflector: • Size, shape, and manufacturing method • Optics • Feed and illumination • Polarization purity • Net bandwidth • Etc. • Measurements on DVA-1 • 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 • 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

  25. 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 designUtilization 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 <10KPointing stability: <1% gain variation @ ½ power point (1.4 GHz.)Minimum 30 year lifetimeMinimum 1 year maintenance interval (target 5 year) DVA1 Meeting at NSF

  27. 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 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 • Reflectors • Backup structure • Pedestal • Indexer • Feeds and receivers • Interface to EVLA network and correlator • Test site (and reflector fab) • Testing plan and elements • single-dish tests • array tests • Decommissioning of DVA-1 • Detailed schedule • Management • Organizations, Personnel and Org chart • Funding and funding profile • MoA or MoU? DVA1 Meeting at NSF

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