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 – 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


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


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)


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


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


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


Reflector design options

Single composite shell and sparse support framing

Dual shell reflector and support, composites

15-16 April 2010 8DVA1 Meeting at NSF

Feed Options to Cover 0.3 to 10 GHz (nominal)


Canadian CART program + TDP Work by Matt Fleming:


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


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


Management of DVA-1To 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


DVA Context&

DVP Goals

P. DewdneyApr 15, 2010

SPDOSystem Hierarchy (Part 1)

16

Telescope

Dish WBSPF

Receivers

SKA User System

Dish Array

Sparse AAArray (Low)

Dense AAArray

Receptors

Feed elements

LNA

People L6System

L7User System

L5Elements

L4Sub systems

L3Assemblies

L2Sub-assemblies

L1Components

Beamformer

Cryo Feed

L0Parts

PAF

LNA

Receptors

Feed elements

LNA

Beam former

Beam management

Beam management

Sparse AAArray (High)

Receptors

Feed elements

LNA

BeamformerBeam

management

To Figure

B

DVP

SPDO

System Hierarchy (Part 2)

17

Facilities L6System

L7User System

L5Elements

L4Sub systems

L3Assemblies

L2Sub-assemblies

L1Components

L0Parts

Power Infra-structure

STaN

Operations and Maintenance

Centre(s)

Regional Centres

Regional Engineering

Centres

Core site

Central site

Off site

SupportVisitor centre

Support HQSupport

Trenches RoadsAntenna

foundations

Core site

Central site

Outlying stations

Core site

Central site

Outlying stations

Water FencesGrid Backup Alternative Stores Workshops Offices

Computing and Software

From Figure

A

Signal Processing

Facility

SignalProc

Channeliser and

Correlator

Non visibility

processor

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.

Dish Verification Program (DVP)

18

SPDO• 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).

DVP Goals

19

SPDO

Integrated Approach

20

SKA Science Case

DRM Analysis

ConceptsMemo 100

Risk Management

Plan

Technologies

DRM

Requirements DevelopmentAnalysis Validation

Risk mitigation strategies and projectsVerification programmes (DVP, AAVP, other domains), Design studies, Precursors, Pathfinders

PDR

Selections for reference designRisks

System Definition Phase System Prelim Design Phase

DesignFunctional analysis, verification and synthesisDesign verification

High level requirements

SRR

CODR

Requirements (Development, Analysis , Validation)PDR

Definition Phase Prelim Design Phase

Design (Functional analysis, verification and synthesis, Design verification)

SRR

Concept Phase

Concepts

CODR

ELEMENTS

Concept Phase

SYSTEM

RISK MANAGEMENT

Tradeoffs

Tradeoffs

RisksDVAs

SPDO

Time Scale

21

PreliminaryDesign

Concept definition Sub-System DefinitionDetailedDesign Site Assembly, Integration and Testing

CoDR

Preliminary Design

CoDR SRR PDR

rep

ortRFI Monitoring

Site Acceptance tests including RFI qualificationSite

Engineering

Dishes

Signal Processing

Imaging ConceptSoftware Requirements DefinitionPreliminary high level architecture

On-site TestingPhase 1 Refinement and Roll-out

CoDR PDR

Software & Computing

Signal transport & Networks

Concept Definition Dishes, AAs

Dish Sub-Sys. Definition

DVA1Dish Prototype

Fabrication

DVA1Prototype Dish Testing

Site Assembly, Integration and Testing

2009 2010 2011 2012 2013 2014 2015 2016 2017 2018

Prototype AAVS1 Testing

SRR PDR

Sub-System Definition

CoDR PDR CDR

CDR

RQZSite characteristicsAtmospheric studiesConfiguration studies

CDR

Milestones

Baseline design for Phase 1

Site decision Costed system design

AA Sub-Sys. Definition

AA Prototype Fabrication

2009 2010 2011 2012 2013 2014 2015 2016 2017 2018

Remote Station Land Acquisition & Environmental Studies

Continued RFI and Tropo Monitoring

Temporary Software Correlator

Phase 2 Continuation





S/W Development & Roll-out for Phase 2


Phase 2 Correlator Design

Monitoring & Control

Data Storage

CDR PR

CDR PR

SRR

Hardware Correlator Early Fabrication

PRFactory Assembly, Integration and Testing

Site Assembly, Integration and Testing

SRR

PDR

Front End and Channeliser

Beamformer and Correlator

Pulsar and Transient Processor

Start of Phase 2

Construction

Phase 2 …..

Phase 1 Construction, Verification, Commissioning, Acceptance, Integration & First Science

Detailed Design, Prod. Eng& Tooling

SKA Preparatory Phase

Refine high level architecturePreliminary Design

Ops and Maintenance Facility

Tooling and Early Fabrication

Purchase or Fabrication

Detailed Design

Detailed Design, Coding, Integration with platforms and testing

Central Data Processing Facility

Science Computing Facility

Start of Phase 1 Construction

Factory Assembly, Integration and Testing

Factory Assembly, Integration and Testing

Rev 7a2010-04-13

Definition and DesignPhase 1 System Testing

SRR

System Engineering

CoDRPhase 1 Systems integration

PDR CDR

Phase 1 Verification and CommisioningSystem refinement, change management

Final SKA Deployment PlanProject management

PM Plan &

Schedule

SKA Scope definitionPrepSKA Plan Project staffing & developmentWBS, resource allocation

CoDR PDR CDR

REV REV

Science DRM Development

Revision of Science Case

REV

Refinement of Early Science Shared Risk Science Operations

REVPhase 2 Science Development

REV REV

Science / Engineering tradeoffs

Early Science Proposals

Continued System Engineering for Phase 2

Continuous Performance Evaluation

Project execution, monitor and control

Infrastructure Detailed Design (fibre & power)

Antenna Foundations and Trenching Roll out

Phase 1 construction

approval

Infrastructure Detailed Design (buildings)

CDR

Concept Definition AAsAperture Arrays

DVA2 development and testing

AAVS2 development and testing AAVS2 demo

PDRSRRCoDR CDR

DVPReview dates are preliminary.

SPDO

Time Scale

22

Review dates are preliminary.

CoDR

Dishes Concept Definition

Dish Sub-Sys. Definition

DVA1 Prototype Fabrication

DVA1Prototype Testing

2009 2010 2011 2012 2013 2014 2015 2016

SRR PDR

Milestones


Site decision Costed system design

2009 2010 2011 2012 2013 2014 2015 2016

CDR PR

Phase 1 Construction

Detailed Design, Prod. Eng& Tooling

SKA Preparatory Phase

Tooling and Early Fabrication

Start of Phase 1 Construction

Rev 7a2010-04-13

Phase 1 construction

approval

DVA2 development and testing

Extra


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)

15-16 April 2010 DVA1 Meeting at NSF

• 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 <10KPointing stability: <1% gain variation @ ½ power point (1.4 GHz.)Minimum 30 year lifetimeMinimum 1 year maintenance interval (target 5 year)

•


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


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?


goals of dva-1 meeting

Documents

2010dva1 meeting

nsfdva1 meeting

ska antenna

nsf feed options

ska feedsreceivers

antennas program

multiple feeds

suite of feeds