1 / 20

Example Configuration (Phase 2)

Casper Signal Processing Workshop 2009 SKA Signal Processing (Preliminary) Wallace Turner Domain Specialist for Signal Processing. Example Configuration (Phase 2). Memo 100 identifies the following options: 70-200MHz: Sparse AA 200-500MHz: Sparse AA 500MHz-10GHz: 3000 15m dishes Or

luann
Download Presentation

Example Configuration (Phase 2)

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Casper Signal Processing Workshop2009SKA Signal Processing(Preliminary)Wallace TurnerDomain Specialist for Signal Processing

  2. Example Configuration (Phase 2) Memo 100 identifies the following options: 70-200MHz: Sparse AA 200-500MHz: Sparse AA 500MHz-10GHz: 3000 15m dishes Or 500MHz- 10GHz: 2000 15m dishes with PAFs plus WBSPF Or 500MHz-10GHz: 250 Dense AA plus 2400 15m dishes/ WBSPF Note: On going discussions 15m vs 12m dishes Example Configuration with Dense AA + SPF

  3. Reference Design

  4. Dishes+Single Pixel Feeds American: 6m Hydroformed Dish South Africa: 15m Composite Dish Note: On going discussions 12m vs. 15m dish Required sensitivity 10,000 m2K-1 Correlator processor and dump rate proportional to Nant2 ADC likely to be at antenna (4 bit ?) O/Prate = fs.4bits = 160 G bits/s per antenna Where fs= sample rate likely to be split into smaller basebands Canadian: 10m Composite Dish

  5. AGN Science Chapter Example AGN Science Chapter Survey Speed: 1 x 105 m4K-2deg2 Frequency range 500 MHz to 8GHz Tsys now: Not achieved over bandwidth Target Tsys: 35K

  6. Dishes+Phased Array Feeds ASKAP Australia: Checkerboard Array Apertif Netherlands: Vivaldi Array Note: Some Channelization and Beamforming likely to be at antenna. Maximum Field of View limited by Array size and focal length of dish. Achievable field of view limited by network bandwidth. PHAD Canada: Vivaldi Array

  7. Example Number PAFs Required Wide Field Polarimetry Science Chapter Survey Speed: 5 x 108 m4K-2deg2 Max frequency 2GHz WBSPF would require over 15,000 dishes Tsys now: 100 K Target Tsys: 50 K

  8. Simplistic View of PAF Processing • Consider Frequency Domain Beamforming • Channelisation: Nchan ~ 64 • 12 taps gives < 60db aliasing between channels • Processing load ~ (Ntaps + 3*log2(Nchan)) x Nel x 2pol x fs • Ntaps = 12, Nel = 96 x 2pol & fs= 1.4 GHz for 700MHz bandwidth Processing load = 8 x 1012 MACS • Beamformer (per antenna): • Average beams per channel 30 • Processing Load = Nbms.Nel.2pol.fs. 4Multiplies = 3 x 1013 Macs • O/Prate= Nbms.2pol.fs.4bits.8B10B = 420 G bit/s • 42 10 G bit/s optical cables per antenna • Includes 25 % extra bandwidth required for 8B/10B Encoding • 2000 dishes with PAFs (total 840 T bits/s) Note :*FFT implementation dependent

  9. Sparse Aperture Arrays LOFAR: Netherlands et al Note: Two types of sparse AA required: 70MHz – 200 MHz 200MHz – 500 MHz Only solution for EoR HI Science Chapter LWA: USA MWA: USA & Australia

  10. Dense Aperture Array Station Assumed Dense Aperture Array ~256 tiles x 256 elements per tile 2 polarisations per element Sample rate ~ 2.5 G Hz 4 bits/ sample 56 m diameter 250 stations Tsys now 120K Target 35K Memo 100 Dense AA Detail 300MHz to 1GHz i.e. 700MHz bandwidth fs=2 x 700 MHz 56m diameter array =>2463 m2 44.4 2pol elements per m^2 (30 cm wavelength) = 110,000 elements x 2pol per station, about 2 x 64k elements. Array efficiency 80%, Bore efficiency 75% & Tsys = 35K -> 250 stations for 10,000m2K-1 sensitivity Processing Bunker

  11. Simplistic View of Dense Aperture Array Processing • Consider Frequency Domain Beamforming • Delay is implemented as a phase slope in frequency domain. • Alternative time domain with tuned lengths of co-ax. • Channelisation: Nchan 1024, • 12 taps gives < 60db aliasing between channels • Ntaps = 12, Nant = 64k x 2pol & fs= 1.4 GHz for 700MHz bandwidth • Processing ~ (Ntaps + 3*log2(Nchan)) x Nant x 2pol x fs**=8 x 1015 MACS • Beamformer (per station): • Average 1437 beams per channel to cover 250 sq degrees FoV • Processing Load = Nant.2pol.Nbms.fs. 4MACS = 1 x 1018 MACS • O/Prate**= Nbms.2 pol.fs.4bits.8B10B = 20 T bit/s • Over 2000 10 G bit/s optical cables, 8B/10B Encoding factor 1.25 • Up to 250 Dense AA Stations (total 10 peta bits/s) Note :*FFT implementation dependent **Ignores upsampling of channelizer

  12. Correlator Processing Loads • Channelisation (700MHz bandwidth): • SPF 4 x 1014 (105 channels) • PAF 4 x 1012 (4096 fine channels giving ~ 105 total) • Dense AA 6 x 1015 (128 fine channels ~ 105 total) • Correlation load (700 MHz bandwidth) • SPF load = 6 x 1016 MACS • PAF load = 1 x 1018 MACS • Dense AA = 2 x 1018 MACS • Correlator Dump Rate (Dish Solution) • 2280 15 m dishes + 40 x 18 dish stations and 3000 km baseline: • Integration time ~ 200ms for < 1% smearing 5 x 106/2 baselines x 105 channels x 4 bytes x 5 Hz = 9 T Bytes/s Not calculated for other configurations yet

  13. Signal Processing Overview Memo 100 Option a* * Sparse AAs + 3000 15-m dishes with SPFs

  14. Signal Processing OverviewMemo 100 option b* Possibly include a beam former for the core * Sparse AAs + 2400 15-m dishes with PAFS & WBSPF

  15. Signal Processing OverviewMemo 100 option c* * Sparse AAs + 250 Dense AA + 2000 15-m dishes with SPFs

  16. Technology Options • FPGA • Virtex 6 (available 2010): 2016 x DSP slices clocked at 600 MHz -> 1200 G MACS ~ 25 G MACs per Watt 1018 MACS requires ~ 106 FPGAS => 48 W per device and ~ 48 M Watts for 1018 MACS Operating cost 1$ per Watt per year => $48M per annum Plus cost of cooling and delivering power • ASIC • 22nm (available 2010): 2.5 nW/MHz/Gate > 40 T MACS (4 bit) per device => 25,000 devices Assuming < 50 % gates switching at any one time: 600kW Operating cost $600k per annum

  17. What would F or X unit look like? Baseline Board (rear) Station Board EVLA style boards might be an optiton ? 64 ASICS or FPGAs on board (~1.5 kW card) ~ 190 boards for Dense AA ASIC correlator 14 cards per shelf -> 14 shelves Is production yield an issue? Could use smaller 8 processor chip board As per ASKAP or Uniboard Inter-board Communication links increase Baseline Board (front) Pictures courtesy Brent Carlson

  18. Multichip Module • SKADS have developed a promising Multichip Module: • 4 x 4 antenna array currently, • Current RFI Protection shows -57dB per M (in air) • Could be developed and used in several areas of the SKA • (Note that the key components are ADC and Optical I/O, although the others could be useful in some applications.) Picture courtesy of Kris ZarbAdami

  19. Correlator Centre Build Cost • ASIC solution • 1 cabinet per 30 sq ft • Between 80 & 160 cabs? • Factor of 4 for air con &PSU units, offices • ~ 50 W per sq ft Kevin Wohlever 2006

  20. SPDO Team Project Director Richard Schilizzi Project Engineer Peter Dewdney Executive Officer Colin Greenwood Project Scientist Joe Lazio System Engineer Kobus Cloete Domain Specialist Receptors Neil Roddis Domain Specialist Signal Transport Roshene McCool Domain Specialist Computing & Software Duncan Hall Domain Specialist Signal Processing Wallace Turner Site Engineer Rob Millenaar Project Management Officer Billy Adams Industry Relations Manager Phil Crosby Office Manager Lisa Bell

More Related