SKA System Design Kobus Cloete 9 December 2010 AAVP Workshop "Exploring the Universe with the world's largest radio telescope"

SKA System DesignKobus Cloete 9 December 2010

AAVP Workshop

"Exploring the Universe with the world's largest radio telescope"

SPDOThe System in Context

Level 4

Level 5Subsystem

Level 6System

Level 7User

system

AA-low Infrastructure

System

Dish Array

User System

(See full hierarchy presented as part of R. Schilizzi’s talk yesterday)

SPDO

SKA High Level Conceptual SKA1 System Block Diagram

Single pixel feeds (SPF)

SKA Conceptual

Block Diagram

RegionalScience

Centre(s)

RegionalEngineering

Centre(s)

ScienceComputing

Facility

Remote cluster

Remote cluster

Remote cluster

Remote cluster

Remote cluster

Operationsand

MaintenanceCentre

CentralSignal

ProcessingFacility

On Site

SKA HQ(Off Site)

Global

High Performance ComputingData Storage

Central BeamformingCorrelation

Non-visibility Processing

SKA ConceptualHigh Level

Block Diagram

Drawing number : TBDDate : 2010-09-29

Revision : F

Remote clusterson spiral arm

(only one arm is shown)

Mid Frequency Aperture Array

(AA-Mid)

Low Frequency Aperture Array

(AA-Low)

DishArray

Wide band SPF

(WBSPF)

Phased array feeds(PAF)

AIP

AIPA

IP

SPDOSKA Memo 125

SPDOMemo 125 – Summary (1)

• Definition of Baseline– Low frequency sparse aperture array– Dish array– Signal transport and networks– Correlator and Non visibility processor– Central Data Processing, Science Processing and System

Software.– Central timing and synchronisation subsystem, including time

and frequency reference distribution,– Infrastructure (buildings, roads, facilities, labs etc.),– Power delivery and distribution,– Support and maintenance equipment and facilities

SPDOMemo 125 – Summary (2)

• Advanced Instrumentation Program– Dense Aperture Arrays– Phased Array Feeds– Ultra Wide band Single Pixel Feeds

• Decision points for AIP identified– 2016, or– As modular sub-systems of the SKA1 dishes

• How do we continue with the SKA definition and design and at the same time take all of these aspects into consideration?

SPDO

To this!

1. How do we get to this?2. How do we move from this …..

SPDOChallenges

• Challenges include:– Maintaining a focus on full SKA– Definition of potential Phase 2 envelopes to ensure Phase 1

extensibility for example: Scope of the infrastructure to be developed for Phase 1 balancing cost and Phase

2 view/extension– Selection of receptor technologies for Phase 2 in 2016 implies that the

full scope, definition and design of Phase 2 will only be finalised after selection

– Potentially higher costs because of wrong choices and resulting rework

– Degree of integration of the AIP receptors with the Phase 1 instrument

– Guard against discontinuity in buildout– Carry risks for longer

SPDORoute to SKA

• How do we continue with the SKA definition and design and at the same time take all of these aspects into consideration?

• Recently a conceptual Route to SKA was developed attempting to maintain the structure of the project but at the same time maintain flexibility to accommodate all the identified future enhancements.

• Always maintain focus on the full SKA.

SPDOGraphical Representation (from PEP)

TR Levels

200

9

201

0

201

1

201

2

201

3

201

4

201

5

201

6

201

7

201

8

SK

A1

B

ase

line

D

esi

gn

Site

de

cisi

on

Co

ste

d s

yste

m

de

sig

n

SK

A1

co

nst

’n

ap

pro

val

Sta

rt o

f S

KA

1

Co

nst

ruct

ion

& A

IP D

eci

sio

n

201

9

202

0

202

1

202

2

202

3

202

4

202

5

202

6

Sta

rt o

f S

KA

2

Co

nst

ruct

ion

SK

A2

Sh

are

d-

Ris

k O

bse

rvin

g

UserRequirements

SystemRequirements

Architectural SystemDesign

Sub-System andComponent Design

Build

Sub-System Integration,Verification & Testing

Integration, Verification &Testing

SystemVerification

SystemValidation

Co

nce

pt,

D

efin

itio

n

Pre

limin

ary

De

sig

n

De

taile

d D

esi

gn

, B

uild

&

Te

st S

ub

-Sys

tem

s

Sys

tem

In

teg

ratio

n

an

d T

est

ing

1 2 3 4 5 6 7 8 9

Part A

SK

A2

SK

A1

Part B

AIP

SPDO

SKA2Preliminary system

design

OK to finalizeSKA2 design?

Adjust SKA2 scope

SKA2 DecisionEvaluate SKA2 system. Optimise SKA2 system for selected technologies.· PAF technology· DAA technology· BL technology· WBSPF technologyConsider:· AIP outcomes· Cost/performance tradeoff· Risk· Total System Cost· Schedule· SKA1 ops experience· Requirements

· Functional· Non-functional

Pre

limin

ary

Des

ign,

Cos

t/Per

form

ance

Tra

de-o

ffs fo

r S

KA

2,co

nsid

erin

g A

IP te

chno

logy

.

Yr 2016

Start

Define initial science requirements for SKA1.

(Subset of DRM)

Define SKA1technical requirements

Define initial science requirements for SKA2,

extracted from DRM

Evaluate SKA1 system:· Cost/performance tradeoff· Extensibility from SKA1 to

SKA2

OK to finaliseSKA1 design?

Adjust SKA1scope

Detailed design for SKA1

Yes

Carry out first order SKA2 system designs, based on 4 technology

combinations.

Extract SKA2 Extensibility Requirements for SKA1

Construct & continuously evaluate SKA1

Operate SKA1 to generate science results


Operate theFinal SKA

Construct & continuously evaluate SKA2 in

parallel with operating SKA1

Analyse SKA2 requirements to develop

AIP technical requirements

Yes

Element/subsystem design, based on SKA2

requirements.

Detailed verification programme design.

Develop, build, deploy prototype(s).

Carry out verification, using a small set of

converging prototypes.

Continue to track and refine SKA2

requirements.

SKA1 SKA2 AIP

Note: options are:[1] Baseline Design (BD)[2] BD + Phased Array Feeds[3] BD + Dense Aperture Arrays[4] BD + Ultra-Wideband Single-Pixel Feeds


design

Site Decision

Sufficient maturity demonstrated to consider

in SKA2 design?

Yes

Drop immature technology

No

Con

cept

, Def

initi

on

Pre

limin

ary

Des

ign

Con

cept

, Def

initi

on &

E

arly

Pre

limin

ary

Des

ign

Def

initi

on AIP

Detailed Design, Build,Test, Integrate

Det

aile

d D

esig

nB

uild

,T

est,

Inte

grat

e

Pre-Construction

SKA1 ConstructSKA2 Design

Yr 2016

SPDO


design

OK to finalizeSKA2 design?

Adjust SKA2 scope

SKA2 DecisionEvaluate SKA2 system. Optimise SKA2 system for selected technologies.· PAF technology· DAA technology· BL technology· WBSPF technologyConsider:· AIP outcomes· Cost/performance tradeoff· Risk· Total System Cost· Schedule· SKA1 ops experience· Requirements

· Functional· Non-functional

Pre

limin

ary

Des

ign,

Cos

t/Per

form

ance

Tra

de-o

ffs fo

r S

KA

2,co

nsid

erin

g A

IP te

chno

logy

.

Yr 2016

Start

Define initial science requirements for SKA1.

(Subset of DRM)

Define SKA1technical requirements

Define initial science requirements for SKA2,

extracted from DRM

Evaluate SKA1 system:· Cost/performance tradeoff· Extensibility from SKA1 to

SKA2

OK to finaliseSKA1 design?

Adjust SKA1scope


Yes

Carry out first order SKA2 system designs, based on 4 technology

combinations.

Extract SKA2 Extensibility Requirements for SKA1

Construct & continuously evaluate SKA1

Operate SKA1 to generate science results


Operate theFinal SKA

Construct & continuously evaluate SKA2 in

parallel with operating SKA1

Analyse SKA2 requirements to develop

AIP technical requirements

Yes

Element/subsystem design, based on SKA2

requirements.

Detailed verification programme design.

Develop, build, deploy prototype(s).

Carry out verification, using a small set of

converging prototypes.

Continue to track and refine SKA2

requirements.

SKA1 SKA2 AIP

Note: options are:[1] Baseline Design (BD)[2] BD + Phased Array Feeds[3] BD + Dense Aperture Arrays[4] BD + Ultra-Wideband Single-Pixel Feeds


design

Site Decision

Sufficient maturity demonstrated to consider

in SKA2 design?

Yes

Drop immature technology

No

Con

cept

, Def

initi

on

Pre

limin

ary

Des

ign

Con

cept

, Def

initi

on &

E

arly

Pre

limin

ary

Des

ign

Def

initi

on AIP

Detailed Design, Build,Test, Integrate

Det

aile

d D

esig

nB

uild

,T

est,

Inte

grat

e

Pre-Construction

SKA1 ConstructSKA2 Design

Yr 2016

SPDOSKA1

• From the SKA1 science requirements (Memo 125)– Derive the SKA1 technical requirements – Develop initial SKA2 system technical requirements based on

the science requirements contained in the Design Reference Mission (DRM).

• Derive all other requirements• Perform preliminary system design for SKA1

– To be informed by early preliminary designs for the SKA2 options, so as to ensure extendibility to SKA2.

– Tradeoffs of performance against cost.• Full detailed design for SKA1.

SPDOSKA2

• To inform the SKA1 design process– Draft initial technical requirements for the four

system options for SKA2 (Baseline Technology alone + the three AIP options in combination with the Baseline Technology),

– Carry out early preliminary system designs for each of the options.

• Continue to track Phase 2 requirements to prepare for a decision on technology selection in 2016.

SPDOAIP

• The AIP will build up the level of maturity in anticipation of their utilisation in SKA1 and SKA2.

• General steps:– Analyse the SKA requirements to maximise potential to

enhance system performance, achieve more of the initial system requirements and/or reduce cost, as compared with the baseline.

– Develop a preliminary design assuming the particular AIP technology will be used at the element or subsystem level of the system.

– Carry out a verification program to test the level of achievement of requirements, to develop performance/cost models for the AIP technology, and to ascertain remaining risk.

SPDORequirements emanate from various sources

Health and

Safety

Regulatory

ScienceOperations

Maintenance and support

Science

Other Constraints(Virtual Observatory,

VLBI, TOO interface, web delivery interface)

NaturalEnvironment

Technology

System

Humanfactors

Users,Operators,Scientists

SecurityExisting

Infrastructure

Sources of interestExternal RFI

Environment

Academic and Science institutions(Local and global)

Local communities and environment

(cultures)

Transitioning between phases

Performing science operations while construction is

proceeding

ObsolescenceStandardisationSkill level of maintainersTest equipmentSimulators….

SPDOFlow of requirements

Science and others

System

Element

Sub-system

Existing Solution 1

Comply to?

Existing Solution 2

Requirements

Requirements

Requirements

Top - down

Bottom - up

New Solution

SPDOProcess in more detail

CoDRs

System

Element 1

System

Element 2

Element 3

Element 1

Element 2

Element 3

SRRs

Subsystem 1

System

Science and other requirements

Science and other requirements

Subsystem 1

SPDOHow does it all fit together?

Time

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

Risks

(More comprehensive view)

Memo 125

SPDOVerification Programs

• Example considerations:– What is the aim of the verification program?– Which requirements will be verified and how? – If not all, will a next development model be built and

tested to verify these requirements?– Other considerations?

SPDOWhere are we?

• System CoDR was held in February 2010– Provided guidance an all these aspects– Documents available at WP2 wiki:

http://www.skatelescope.org/public/2010 02_System_CoDR_Documents/‐

WP2 wiki• Memo 125• System documents being reworked for delta CoDR in February

2011• Will be followed by element level CoDRs during 2011• System Requirements Review in 2012.

SPDOOther presentations for reference

• Annual WP2 meeting (October in Oxford)– Presentations available of SKA Indico Site– Turner

Systems Methodology for the SKA– Dewdney

Refining the DRM & Deriving Technical Requirements– Cloete

System Design Plan System Engineering Tools and Strategies WP2 planning and Beyond PrepSKA

– McCool, Hall, Bolton Costing Strategy

SPDOThank you