Review of developments in Australasia and mainland Asia

Steven TingaySwinburne University of Technology

Next Generation correlator meeting, JIVE27 - 29 June, 2006

http://astronomy.swin.edu.au

1. Current correlator developments in Australasia

• CABB (Ferris: Day 1)• SKAMP (Bunton: Day 3; de Souza: Day

3)• NTD/xNTD (Bunton: Day 3) - Langman: Day 3• LFD (Bunton: Day 3)

• VLBI/eVLBI (Deller: Day 2)

2. Current correlator developments in mainland Asia

• PAST• FAST• VLBI/CE-1 (Zhang: Day 1; Weimin: Day 2)• GMRT (Gupta: Day 1)

Horses for courses………

Compact Array Broadband Backend (CABB)

First major upgrade to ATCA correlator since construction in 1988 (CABB funded under MNRF2001)

Current ATCA correlator:• 6 antenna inputs;• 2 dual polarisation (linear) IFs (∆MAX = 128 MHz);• XF;• max number of channels = 4096;• ASIC-based.

CABB:• 8 inputs (2 extra for VLBI or RFI mitigation);• 2 dual polarisation (linear) IFs (∆MAX = 2 GHz);• polyphase digital filter bank for channelisation,

then cross-multiply; • max number of channels = 2000 (initially);• FPGA-based.

Phased introduction of operational system over next 2 Years

Dick Ferris to present details (http://www.atnf.csiro.au/projects/mnrf2001)/

SKA Molonglo Prototype (SKAMP)www.physics.usyd.edu.au/astrop/ska/ (John Bunton/Ludi de Souza)

– 96 stations (feeds), digital filterbank FX, FPGA-based;;– Stage 1: continuum, ∆ = 3 MHz @ 843 MHz;– Stage 2: 2048 channel spectral line, ∆ = 30 MHz @ 843 MHz;– Final: 2048 channel spectral line, ∆ = 100 MHz @300 - 1400 MHz

(Extended) New Technology Demonstrator (NTD/xNTD) www.atnf.csiro.au/projects/ska/xntd.html (John Bunton)

– 20 x 15m dishes, FPA with >30 beams;– 22800 baseline/polarisation products, ∆ = 256 MHz ;– Spectral-line, FPGA-based (same correlator board as SKAMP??);– Very similar instrument to KAT (Alan Langman);– Located at Mileura station in Western Australia.

Low Frequency Demonstrator (LFD)www.haystack.mit.edu/ast/arrays/mwa/LFD/index.html (John Bunton)

– 500 tile array with full stokes, ∆ = 32 MHz , 4000 channels;– Common correlation engine with SKAMP and NTD/xNTD;– CSIRO/MIT/University joint project;

DiFX software correlator

astronomy.swin.edu.au/ska (Adam Deller)www.atnf.csiro.au/vlbi/documentation/VLBI_National_Facility_upgrade.html

Complements new high data rate disk-based recording system

• 300 processor Beowulf cluster/Cray XD-1/Cray XT-3;• FX correlator (filter bank option);• Services Australian and global VLBI arrays;• Six antennas up to 1 Gbps (∆ <= 128 MHz);

• Currently offered as part of ATNF (high sensitivity, high spectral resolution, niche experiments);

• Will replace ATNF S2 correlator (<128 Mbps and <4096 channels) within 12 months;

• Natural compatibility with all other disk-based recorders (Mark5, K5, PC-EVN etc);

• Used for eVLBI tests and real-time fringe checking;

• Promotes collaboration in non-traditional but important areas.

Primeval Structure Telescope (PAST)web.phys.cmu.edu/~past/overview.html

– Observe the epoch of reionisation at redshift 6 - 20;– 80 phased arrays x 127 antennas per phased array;– 10,000 log periodic antennas in the Ulastai Valley, China;– Software correlator using ~100 COTS PCs.

Five hundred metre Aperture Spherical Telescope (FAST)

– Multi-beam receivers for surveys;– Wide bandwidth, full polarisation;

VLBI spacecraft tracking/Chang’E-1 Lunar missionReal-time software correlator (Zheng Weimin, XiuzhongZhang)

– Determination of lunar orbiter position, lunar gravity field;– Correlation in software a la Huygens VLBI experiments;– Real-time correlation with COTS PC cluster.

Giant Metrewave Radio Telescope (GMRT)(Yashwant Gupta)

– 30 x 45m antennas, 150 - 1420 MHz;– Bandwidth upgrade from 32 MHz to 400 MHz;– Upgrade of current 30 antenna, 256 channel, FX

correlator required -> 32 antenna, 8192 channel;– Enhanced beamforming capabilities for multi-beam pulsar

searching;– Software vs hardware ???

Summary

• A lot of diverse activity across the region.

• Large and small developments, upgrades (e.g. CABB, SKAMP, GMRT) and new facilities (e.g. xNTD, FAST, LFD);

• SKA demonstrators (CABB, SKAMP, xNTD, LFD, FAST);

• Niche facilities (Software correlators for VLBI);

• Specialised experiments (PAST);

• Other small developments (e.g. Uni.Tas. FPGA developments)

• Other planned/proposed developments (e.g. Australian geodetic VLBI array using software correlator.)