Transcript Document
Review of developments in Australasia and mainland Asia Steven Tingay Swinburne University of Technology http://astronomy.swin.edu.au Next Generation correlator meeting, JIVE 27 - 29 June, 2006 1. Current correlator developments in Australasia • • • • CABB SKAMP NTD/xNTD LFD (Ferris: Day 1) (Bunton: Day 3; de Souza: Day 3) (Bunton: Day 3) - Langman: Day 3 (Bunton: Day 3) • VLBI/eVLBI (Deller: Day 2) 2. Current correlator developments in mainland Asia • • • • PAST FAST VLBI/CE-1 GMRT (Zhang: Day 1; Weimin: Day 2) (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 mission Real-time software correlator (Zheng Weimin, Xiuzhong Zhang) – 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.)