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Arnold van ArdenneAAVP overviewAAVP_AvA08122010Courtesy: Lofar & SKADS/AAVP teams

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Arnold van ArdenneAAVP overviewAAVP_AvA08122010

Effelsberg (D)

Tautenburg (D)

LOFAR Stations Across Europe

Potsdam (D)

Unterweilenbach (D)

Exloo (NL)

Chilbolton (UK)

Nançay (F)

Onsala (Sw)


~ 300 Dishes

~ 50 Sparse Aperture Array

Stations

70 – 450 MHz

Central

Region

Single pixel feed

450 MHz – 3GHz

Baseline design for SKA1;

Array & Receptor Technologies

Artist renditions from Swinburne Astronomy Productions,

courtesy: SPDO


and in parallel

The Advanced Instrumentation Program

Further development of innovative wide-field “radio camera”

technologies with the potential to enhance Phase 1 and be a major

part of Phase 2:

• dense aperture array

• phased array feeds (PAFs) on the dishes

Decision in 2016


~ 250 Dense Aperture Array

Stations 300-1400MHz ~ 2700 Dishes

~250 Sparse Aperture Array

Stations 70-450MHz

3-Core

Central

Region

Advanced Instrumentation

Program SKA2

Artist renditions from Swinburne Astronomy Productions,

courtesy: SPDO


Planning for this decade

detailed design

& pre-

construction

2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023

prototyping and

costing 1st gen.

instrumentation

construction,

commissioning (AIV)

& shared-risk obs.

technology development ,

prototyping and costing

2nd generation instrumentation

detailed design &

pre-construction

2nd gen. instr.

construction,

commissioning (AIV)

& shared-risk obs.

Selection of 2nd generation instrumentation

System Design ,Infrastructure,

Costing, Detailed Design,Pre-Constr.SKA1 science operations

Enddate MOA

Enddate PrepSKA WP2

AAVP


Principal Deliverables in time

AA-lo technology demonstrator & costed sub-system design 2013

SKA1 full pre-production prototype array 2015

SKA1 manufacturing data package 2015

AA-mid single array performance demonstrator 2013

multi-array interferometer performance demonstrator 2015

SKA1 capable costed design 2015

AA system AA-lo and AA-mid CoDR 2010

SKA2 technology roadmap & costed system design 2015


SKA Widefield System scenario

System concept

Sparse Aperture array

(AA-lo)

250 stations , 180m

Dense Aperture array

(AA-mid)

250 stations , 56m

Dishes with single pixel

feed

1200 dishes, 15m

Freq. Range 70 MHz to 450 MHz 400 MHz to 1.4 GHz 1.2 GHz to 10 GHz

―Flexible SKA concept with huge science potential ―

Scenario Being studied:

Courtesy: Jason Hessels

& LOFAR Pulsar Working Group

Widely seperated multibeams

key feature in LOFAR and AA’s

In general:


Mapping SKA science cases;

Widefield System scenario

See e.g.SKADS White Paper,

SKA memo 122

Courtesy: Andy Faulkner, Paul Alexander

Area of

Major AA

benefit


Phased arrays; key questions

• Can we afford them within SKA framework

– As investment

– As operating instruments (computationally, reliability, upgradability…)

• Will they perform

– Scientifically (Widefield scanned deep polarimetric Imaging)

– Technically (Noise, beamstability, reliability, ..)

• Will they be there in time

– For SKA Phase1 construction

• What wil be the optimal frequency range

– Related to all the above


AA-relevant background

• Some SKADS Results (publicly available):

• White paper with SKA widefield scenario as key

• Conference book with results and EMBRACE movie (DVD available)

• SKA(DS) memos & publications (www.skads-eu.org)

• Full cycle of Simulations

• Simulated skies (S-cubed) to Astrodata/pipeline,

using MeqTrees, released version MeqTrees, Beamsimulations

• E.M. & Circuit modelling

• Costing tool

• Demonstrators like Embrace/2_PAD/BEST

• Delivered First go on data processing and computing vs. required power


AA-mid pointer: EMBRACE;a first 0.5-1.5GHz Dense SKA-AA Demonstrator

Nancay

?

Courtesy: ASTRON, OPAR, INAF, MPIfR

FOV: ~ 140 sq. deg. / tile beam @ 1200 MHz


Modelling large antenna arrays

• A multi-scale antenna problem — arrays of subarrays

– Total Solve Time: ~10 min.

(Single CPU 1.73 GHz, 2.0 GB RAM) ~35x faster!

• Combining antenna EM-models with MW-circuit models

• An antenna system simulator

Prototype Array HFSSHFSS

M. V. Ivashina, E. A. Redkina and R. Maaskant, “An Accurate Model of a Wide-Band Microstrip Feed for Slot Antenna Arrays”, IEEE AP-S International Symposium, Honolulu, Hawaii, June 2007.

CBFM + Feed Model

+=

M. V. Ivashina, E. A. Redkina and R. Maaskant, “An Accurate Model of a Wide-Band Microstrip Feed for Slot Antenna Arrays”, IEEE AP-S International Symposium, Honolulu, Hawaii, June 2007.

CBFM + Feed Model

+=

syseff TA /

MW Simulator

+

+

syseff TA /

MW Simulator

+

+

EM Simulator

)(skyT ,iE

EM Simulator

)(skyT ,iE

Using BG:

Courtesy: Rob Maaskant et. al.


Understanding the Noise budget

Expected Aperture Array noise performance

Spill-over 0 K

Vivaldi feed loss 9 K

Low Noise Amplifier ~16 K

Noise mismatch / coupling /2nd stage 7 K

Sky 8 K

Total 40 K

Note:

depends on

scanangle

Measured Active reflection coefficient while scanning:

(noise coupling changes as scan angle changes)

Courtesy: Bert Woestenburg , Dion Kant et. al.

APERTIF in Aperture Array mode showing Tsys<55K

Courtesy: Bert Woestenburg, Laurens Bakker


AA-lo array

• Limited specification available but memo125 reads:

– 70 – 450MHz

– 2000 m2 / K (z=10)

• Interesting pointer WP2 talks e.g. Leon Koopmans (f-lo

50MHz?)

• Single/Dual AA-Lo?

• This Workshop to iterate on specs

AA-low

Low frequency 70 MHz, 50MHz, lower?

High Frequency 450 MHz

AA Type Sparse, Density at lowest

frequency?

Element Single or Dual


SKA Phase 1EMBRACE

2 - PAD

Technology Dev.

StudiesSKA

PositioningProject size:

~18-20M€

100+ FTE

42 month

15 institutes

9 European countries

+ Australia & SA

www.SKA-AAVP.eu

[email protected]

www.ska-aavp.eu/aavpwiki

Sparse Aperture Arrays







Background; AAVP working methods

• WP2.3 of the International SKA PrepSKA WP2

SKA Phase 1 - SKA1 – has AA-lo as a main part

AAVS as part of AAVP is building the AA demonstrators

AAVP Kick off held in March

• AA-System and Technology packages (AA-SDS & AA-Tech) are

―output‖ packages aligned with overall SKA planning

• The verification activity AAVS comprises both AAVS1=AA-low

toward Phase1/SKA-lo and AAVS2=AA-mid toward AIP/SKA-mid

• The Emulation package emulates a test and reference site

(temperature range/cycle, RFI, easy logistics)

• Output through small (~5-10 persons)Task Groups

• Connections to SPDO at all levels, see Structure diagram


ESKAC-Exec +key SH’s+Observers

=AAVP Steering group

SPDO

AA-midASTRON/UK

AA-hi build and test

1. EMBRACE/2PAD eval.

2. AAVS-hi design

3. Industral’n & M/f

4. Site preparation

5. Integrate

6. Calibrate & comm’n

7. Central proc dev.

X. Sub-system dev

AA-lo 1ICRAR

AA-lo single element build and test

1. AAVS-lo design


3. Integrate


5. Performance eval’n

X. Sub-system dev

AA-TechASTRON

Technology development

1. AA-hi array design

2. Tsys Optimisation

3. RF chain

4. ADC & Tile proc’ing

5. Station processing

6. Station calibration

7. Infrastructure

8. AA-lo array design

AA-SDSUK

AA System design studies

1. SSKA level simulations

2. tation level sims.

3. Specify & model AAs

4. Imaging & calibration

5. Cost/Power modelling

6. AA-lo data collection

7. Assess & final reports

AA-lo 2INAF

AA-lo dual element build and test

1. AAVS-lo design


3. Integrate


5. Performance eval’n

X. Sub-system dev

WP1 WP2 WP3 WP4 WP5

Ver. 2.0

AAVP

Organisation

Aperture Array Verification System

AAVP TeamCoordinator Engineer

System Engineer Scientist

AA-SEMPRAC

Develop European Site

1. Site eval’n, selection & requirements

2. Infrastructure dev.

3. Install, commission & test AAs

4. Green energy development

.

WP6

ESKAC

SSEC

PM

AA-loAA-mid

PS/PE


AAVP Short term Activity Schedule

Fully absorb ASTRO2010, PEP toward SKA-1 elements

Fiancially

Technical

Increased focus on AA-lo

Arrive at Update Work Schedule

Update AAVP Activity Document

Funding awaited UK, It, progress not hampered

HW/SW (―stuff‖) funding probably ok till 2012

Optimize for AA global & absorb results from this

Workshop.

Arrive at updated specs (preliminary now)

Prepare for CoDR April 2011

AAVS now preparing SRS & ADD

Discussing updates


Who are presently involved?

Consortium/Institute Country

UK-PrepSKA UK

ASTRON/Kapteyn Inst._RUG/Leiden

Obs._Univ.Leiden Nl

MPIfR Germ.

Obs. De Paris/Obs. Bord./Ud'Orléans Fr

INAF_IRA It

OAN Sp

OSO_ChTU Sw

Torun Centre of Astronomy_UMK Pol

JIVE Europe

PRAC Port

ICRAR Aus

NRF S.A.

SPDO/PrepSKA-WP2

Note: US representative ―only‖ through SPDO


High level questions with (dense)

Aperture Arrays

• Can we make Tsys ―low enough‖? – Probably: uncooled <15K already achieved (JGbdV et.al.)

• Science Verification; Calibration and imaging to the ―required‖ dynamic range in dual pol.?– Cailbration: Reconstructable polarimetric beamshapes (other presentation)Note1: AA have no obstacles and low sidelobes (TBC)

Note 2: Calibration: Intra-, Inter tiles redundancy intrinscially possible, design for

interstation redundancy (other presentation)

• Computational power less problematic for AA’s – See SKADS white paper, SKA memo 108 etc.

• Focus on mass production (methods)

• Cost reduction to an ―affordable‖ level?– Recent: SKA memos 93 & 111

– Preliminary conclusion: Viable SKA with AA & Dishes possible

• Overall power consumption (AAVP); ―greening the SKA‖ (note: PITF)

• Availability/Maintainability/Upgradibility


Potential for Calibration AA’s

• Regular arrangement in phased array stations like LOFAR HBA and

EMBRACE, provides plenty of redundant baselines

• This can be used for inner-tile/inner-station calibration

• Can use: LOFAR HBA’s go from dense to sparse regime > 120MHz

• Now: potential use (e.g. also for diagnoses) and limitations now

being investigated (Parisa Noorishad, Stefan Wijnholts)


SKA-AAVP and Sustainable Society• Position SKA as First Sustainable Energy Mega-science Project

– Society wants it (!,?)

– Example: Zero Carbon Australia Stationary Energy Plan (100% carbon-free in

10yrs)

– European Platform of Universities in Energy Research (EPUE)

• AAVP Activities could/should also focus on

– Sustainable Power supply

– Power use e.g. Self-sustainable AAVP receptors/tiles, low-power processing

– Materials e.g. environmentally friendly

• Key industrial involvement; in Europe:

– Mediterranian Europe in particular Spain, Portugal

– Research supported by EC/ part of ESFRI roadmap (6 projects)

– Other countries e.g. Germany, Siting Countries?, other…


Power: Computations per Kilowatt-hr

Faster

then

Moore!

Blue

Gene/Q


AAVP needs Test Site;

AA-SEM: Site emulation in Portugal• Low RFI

• Low/Excellent RFI conditions & (potential) Radio protected zone

selected in Moura (Contenda Forest)

• Compatibility/comparison with final site shaping to be done

•Tentative conclusion (report available):

• ―>20dB better ― <1GHz

• (much)better >1GHz when compared to WSRT

• Network technology demonstrator site

• Exploring energy related issues wrt SKA durable

energies

• Recent Analysis (AF)

– Total AA station power: Phase 1: 175 kW

Phase 2: 100 kW

• Demonstrator site sustainable energies

• Site development started to be ready March 2011


AA-SEM; Site emulation

Surface Solar Data (MJ/sqrm-day)

0,00

5,00

10,00

15,00

20,00

25,00

30,00

35,00

Jan

Mar

chM

ayJu

ly

Septe

mbe

r

Nov

embe

r

Netherlands

(Maastricht)

Portugal (Evora)

Australia

(Canberra)

South

Africa(Capetown)

Conclusion: Solar Energy levels Evora roughly comparable

with the larger potential SKA site areasSource:Solar Energy Pocket reference (Int.Solar Energy Soc.) 2005, ISBN 0-997128

Hot days Tmax>30; dark red –120-150 days; red – 90-120 days


Summary

• Aperture Arrays shown to work

– LOFAR, EMBRACE

– So far no major blocking encountered

• SKA-AAVP next step to Phase 1 required

– conclude AA R&D phase and technical, science and cost performance

– Arrive at level for informed Phase 1 construction decision

– Same wrt. Phase 2

• Right Time:

– LOFAR/MWA etc. provides important input e.g. wrt.

• Calibration , low frequency science, low cost, processing etc.

– SKADS finished: produced

• Technology ML’s, costing tool, simulations and demonstrators

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