ASKAP Capabilities John Reynolds on behalf of the SEIC and ASKAP team.

ASKAP Capabilities

John Reynolds on behalf of the SEIC and ASKAP team

CSIRO. ASKAP Capabilities

14 May 2009

• Design and construction well underway – many capabilities set

• To ensure highest priority science is delivered fluidity is retained

• Announcement of Opportunity, Oct 2008

• Proposals due in mid-June 2009, evaluation by Aug 2009

• Crystallisation thereafter towards BETR (2010), ASKAP (2013)

ASKAP Capability life-cycle


14 May 2009

• “Mode 1” capabilities already defined• Matching anticipated survey requirements• Continuum imaging• Standard spectral line imaging• Slow transients

• Post-commissioning• Advanced imaging modes (e.g. postage stamps)• “Zoom” (high spectral resolution) modes• VLBI & other “fast transients”

Rollout


14 May 2009

Original capabilities, EoI


14 May 2009

ASKAP Sensitivity (EoI)


14 May 2009

Basics

• 36 antennas (configuration by Gupta, Johnston, Feain 2008)

• 32 beams/antenna• 30deg2 FOV up to ~1.5GHz• 50K Tsys, 80% Aperture Efficiency • 300MHz instantaneous BW, 20 kHz frequency resolution• Frequency range 700 – 1800 MHz, • tunable in 16 MHz steps• Full polarization (auto/cross products on all beams)• 5 second integration time in standard mode


14 May 2009

ASKAP antenna design

12m – prime focus, f/D = 0.5

Alt+Az+polarisation axes (Sky mount)

Surface accuracy 1mm RMS (10 GHz)

Slew speeds 3/1/3 degs/secAcceleration 3/1/3 degs/sec/sec

Settling time < 5 seconds


14 May 2009

Typical u-v histogram for deep image

δ = -50ºT=10h


14 May 2009

PAF design

• 188 elements in octagonal configuration

• 32 x 2 pol formed beams

• Independently steerable

• 30 square degrees up to ~1.5GHz

• Optimal disposition for tesselation not entirely clear

• Interlacing (“dithering”) may be required for flatness of field


14 May 2009

Preliminary design of ASKAP-sized array

11x10 minus some corner elements

188 active pairs


14 May 2009

5 x 6 channel = 30 units13 x 8 channel = 104 units7 x 10 channel = 70 units

Available beams = 188

25 Multi channel LNA PCB's

Total number of LNA's = 204

188 channel FPA LNA Filtercard assembly


14 May 2009

FOV vs # beamsBeams touching at the 3dB points

Beams touching at the 3dB*0.92 points


14 May 2009

Overall ASKAP System

Beamfomer and Fine filterbank

Antenna 1

192 fibre connection


Antenna 2


A/D and Coarse

FilterbankAntenna 36


Antenna 36

192 Analogue

inputs


Correlator Band 1

Correlator Band 2

Correlator Band 16

Tied Array Post processing

(VLBI and Pulsars)

To Computing Centre

Central Site at MRO

Cross connect between

beamformers and correlator

Represents a single Advanced TCA

chassisAll Identical

To Computing Centre

To Computing Centre

To VLBI network

or pulsar processors

A/ Ds located in Antenna Pedestal

A/D and Coarse


192 Analogue

inputs

A/D and Coarse


192 Analogue

inputs


14 May 2009

Mode 1 imaging capabilities

Continuum1 channel + spectral index/curvature OR 256 spectral channelsFull Stokes parameters (IQUV)4k x 4k pixels (2km array) or 12k x 12k (6km array)Real-time source cataloguing

Spectral Line16384 channels (df=18kHz)2 Stokes (I, V)4k x 4k pixels (2km array)Visibilities not archivedLimited number of cubes per day

Slow transients snapshots : 16-channel, 4k x 4k pixel, 2 Stokes

searched every 5 seconds selected images retained


14 May 2009

Modes 2+

Advanced imaging Will be driven by Survey Science Project Design Study (2009-2011)

e.g. “postage stamps”, full 30dB polarization dynamic range

“Zoom” modes16k channels in 4~8 sub-bands, 0.6kHz(*2n) resolution, e.g.;

HI + 1612MHz + (1665-1667MHz)

VLBI – 2~3 tied-array beam voltages,

recorded off-site

frequency standard (H-maser vs Rb)

Fast transientsdiverse requirements vs fluid capabilities

active community consultation happening now


14 May 2009

Fast Transients – capabilities

Flexible correlator – access to; single-dish autocorrelations,

tied-array Voltages or Power,

visibilities (optionally averaging)

formed-beam voltages

flexible user-determined averaging, nStok, nBit …

some on-board capacity for processing, buffering

Constraints

on-site space, power limits & costs

bandwidth to Geraldton (40Gb/s initially, shared)

calibration (requires processing engine)

FPGA programming effort (+testing, commissioning)


14 May 2009

The end

ASKAP Capabilities John Reynolds on behalf of the SEIC and ASKAP team.

Documents

Transcript of ASKAP Capabilities John Reynolds on behalf of the SEIC and ASKAP team.