Upload
todd-richards
View
214
Download
0
Tags:
Embed Size (px)
Citation preview
SETI on the SKASETI on the SKA
Dan Werthimer Dan Werthimer University of California, BerkeleyUniversity of California, Berkeley
http://seti.berkeley.edu/
•SETI historySETI history
•SETI todaySETI today
•SETI future (SKA)SETI future (SKA)
•Signal processingSignal processing
NOT FUNDED
NOT FUNDED
NOT FUNDED
Porno in space:
FUNDED!
First Radio SETIFirst Radio SETI• Nikola Tesla (1899)Nikola Tesla (1899)
– Announces “coherent signals from Mars”Announces “coherent signals from Mars”
• Guglielmo Marconi (1920)Guglielmo Marconi (1920)– Strange signals from ETStrange signals from ET
• Frank Drake (1960)Frank Drake (1960)– Project Ozma Project Ozma
– one channel, 1420-1420.4 MHzone channel, 1420-1420.4 MHz
Traditional SETI dogma: Traditional SETI dogma:
ultra narrow band sine wavesultra narrow band sine waves
barycentric, beacons, FGK starsbarycentric, beacons, FGK stars
21 cm21 cm
Future dogma: Future dogma:
many bandwidths, frequencies,many bandwidths, frequencies,
drifting signals, pulses,drifting signals, pulses,
M stars, galaxiesM stars, galaxies
It’s naïve to think we know how It’s naïve to think we know how best to search today, given our best to search today, given our history of changing SETI history of changing SETI fashion. fashion.
• Multiple strategy is bestMultiple strategy is best
(IR, Vis, Radio, pulse, continuous, targetted(IR, Vis, Radio, pulse, continuous, targetted
sky survey…)sky survey…)
• Half of astronomy discoveries are Half of astronomy discoveries are serendipitous serendipitous
• Examine glitches in data Examine glitches in data
• Data Mining ExperimentsData Mining Experiments
OPTICAL SETIOPTICAL SETI
1961 Charlie Townes Paper 1961 Charlie Townes Paper
largely ingored until 1999largely ingored until 1999
1971 Cyclops report calculates radio >> 1971 Cyclops report calculates radio >> opticaloptical
Today’s lasers can communicate across Today’s lasers can communicate across galaxygalaxy
Optical SETI experimentsOptical SETI experiments
• Lick Observatory Lick Observatory
(Lick, Seti Institute, Berkeley)(Lick, Seti Institute, Berkeley)
• Harvard (targetted Harvard (targetted sky survey) sky survey)
• Princeton Princeton
• BerkeleyBerkeley
10-meter Keck Telescope10-meter Keck Telescope
Survey: 650 F8 – M5 V, IVSurvey: 650 F8 – M5 V, IV
Hipparcos V < 8.5B-V > 0.55 (F8V)Sep > 2 arcsecAge > 2 Gyr
Keck Optical SETI – Data Keck Optical SETI – Data MiningMining
• Geoff Marcy, Amy Geoff Marcy, Amy ReinesReines
• 650 stars (planet 650 stars (planet data)data)
• Echelle Echelle SpectrometerSpectrometer
• Can detect 10KW Can detect 10KW narrow band signalnarrow band signal
(10 KW laser on 10 (10 KW laser on 10 meter telescope)meter telescope)
SETI GOAL:
SkyCoverage * FreqCoverage * Sensitivity^-3/2 * Nsignaltypes
solid angle vs number of nearby FGK stars?
FreqCoverage vs Noctaves?
Pulses vs sinewaves vs drifting vs broadband…?
FreqCoverage, SkyCoverage, signal types: other telescopes
sensitivity: SKA
Radio SETIRadio SETITargetted Search StrategyTargetted Search Strategy
Project Phoenix - Seti InstituteProject Phoenix - Seti Institute
Sky Survey StrategySky Survey Strategy
Serendip, SETI@home - UC BerkeleySerendip, SETI@home - UC Berkeley
Southern Serendip - AustraliaSouthern Serendip - Australia
Meta II - ArgentinaMeta II - Argentina
Seti Italia - BolognaSeti Italia - Bologna
SETI Programs at the SETI Programs at the University of University of CaliforniaCalifornia
NAME TIME SCALE SEARCH TYPE
SERENDIP 1 second Radio sky survey
SETI@home ms to second Radio sky survey
ASTROPULSE us to ms Radio sky survey
SEVENDIP ns Visible targetted
SPOCK 1000 seconds Visible targetted
Dyson Search Years IR excess
University of California, Berkeley SETI University of California, Berkeley SETI ProgramProgram• Graduate Students Graduate Students
Chen Chang, Karl Chen, Paul Demorest, Nia Imara, P. Monat, A. Chen Chang, Karl Chen, Paul Demorest, Nia Imara, P. Monat, A. ParsonsParsons
• Undergraduate StudentsUndergraduate Students
Noaa Avital, Brian Boshes, Henry Chen, Charlie Conroy, Chris Noaa Avital, Brian Boshes, Henry Chen, Charlie Conroy, Chris Day, Daniel Hsu, Wonsop Sim, Ryo TakahashiDay, Daniel Hsu, Wonsop Sim, Ryo Takahashi
• Astronomers and Computer ScientistsAstronomers and Computer Scientists
David Anderson, Bob Bankay, Jeff Cobb, Court Cannick, Eric David Anderson, Bob Bankay, Jeff Cobb, Court Cannick, Eric Korpela, Matt Lebofsky, Jeff Mock, Dan Werthimer, Rom WaltonKorpela, Matt Lebofsky, Jeff Mock, Dan Werthimer, Rom Walton
• Administrative Staff - NoneAdministrative Staff - None
SERENDIP IVSERENDIP IV
• 168M channels168M channels
• 100 MHz Band centered on 1420 100 MHz Band centered on 1420 MHzMHz
• Carriage House 1 line feedCarriage House 1 line feed
• Operating since 1997Operating since 1997
Photos Courtesy NAIC Arecibo Observatory, a facility of the NSFPhotos Courtesy NAIC Arecibo Observatory, a facility of the NSF
Why SETI@home?Why SETI@home?
• Coherent Doppler drift correctionCoherent Doppler drift correction– Narrower Channel Width->Higher SensitivityNarrower Channel Width->Higher Sensitivity
• Variable bandwidth/time resolutionVariable bandwidth/time resolution
• Search for multiple signal typesSearch for multiple signal types– Gaussian beam fittingGaussian beam fitting
– Search for repeating pulsesSearch for repeating pulses
Problem: Requires TFLOP/s processing power.
Solution: Distributed Computing
The SETI@home ClientThe SETI@home Client
5,064,550 participants (in 226 countries)
2,000 per day
2 million years computer time
1,200 years per day
4*1021 floating point operations
65 Tera-flops
SETI@home Statistics
TOTAL RATE
SETI@home in CanadaSETI@home in Canada• 255,426 participants (0.8% of 255,426 participants (0.8% of
population)population)
• 112,000 years of computer time112,000 years of computer time
• 72 million work units72 million work units
Web site: 2 million hits/dayWeb site: 2 million hits/day 200,000 visitors/day 200,000 visitors/day
(stats & games popular; science less (stats & games popular; science less
popular)popular)
100,000 children, families100,000 children, families (including congress members and their kids)(including congress members and their kids)
> 7,000 schools> 7,000 schools
Desired SKA ParametersDesired SKA Parameters
• Wide bandwidthWide bandwidth
• 1 M beams1 M beams
• fat beamsfat beams
• short dwell times (~ 100 seconds)short dwell times (~ 100 seconds)
Gaussian CandidatesGaussian Candidates
BOINCBOINC
• Berkeley Open Berkeley Open Infrastructure for Network Infrastructure for Network ComputingComputing
– General-purpose distributed General-purpose distributed computing framework.computing framework.
– Open source.Open source.
– Will make distributed Will make distributed computing accessible to computing accessible to those who need it. (Starting those who need it. (Starting from scratch is hard!)from scratch is hard!)
BOINC ProjectsBOINC Projects• SETI@home (Berkeley))SETI@home (Berkeley))
• Astropulse (Berkeley)Astropulse (Berkeley)
• ClimateModeling@home (Oxford)ClimateModeling@home (Oxford)
• Einstein@homeEinstein@home (Caltech) (Caltech)
• Folding@homeFolding@home (Stanford) (Stanford)
• ParticlePhysics@homeParticlePhysics@home (CERN) (CERN)
• Stardust@homeStardust@home (U. Wa, Berkeley) (U. Wa, Berkeley)
AstroPulseAstroPulse• Sky surveySky survey
– Covers decs 0 to 30Covers decs 0 to 30
– ~3 years of data recorded so far.~3 years of data recorded so far.
• Good time resolutionGood time resolution– Sensitive to 0.4 µs radio pulses at 21 cmSensitive to 0.4 µs radio pulses at 21 cm
• DM rangeDM range– -1000 to +1000 pc/cm-1000 to +1000 pc/cm33
• SensitivitySensitivity– 1010-18-18 W/m W/m22 peak (Coherent de-dispersion) peak (Coherent de-dispersion)
Piggyback ALFA Sky SurveyPiggyback ALFA Sky Survey• Improved sensitivity Improved sensitivity
– Tsys, integration timeTsys, integration time
• Uniform sky sampling Uniform sky sampling – galactic plane concentrationgalactic plane concentration
• Multibeam RFI rejectionMultibeam RFI rejection
• Larger BandwidthLarger Bandwidth
Search for Optical/Radio Signals from Dyson Sphere Candidates|
Charlie Conroy
• Looked for IR excess from >500 stars
• All stars had age > 1 Gigayear
• 33 stars found with 12m excess
• Searched for anomalous radio detection using SETI@home and SERENDIP IV databases
• Searched for optical pulse emission using OSETI experiment
• Thus far, none of the 33 sources have shown anomalous optical or radio emission
Color excess using 2MASS K band data and 12, 25, 60, & 100 micron IRAS data. An excess at K-[12] is clearly visible and disappears by K-[25]. Dotted lines are Gaussian fits to the distributions. The 33 IR excess candidates have K-[12] > 3 above the mean.
‘‘Prelude’ Precedes SonATAPrelude’ Precedes SonATAIn Fall 2004In Fall 2004For Use On The ATA-32 For Use On The ATA-32
3 beams with 30 MHz each – PCs with accelerator cards
Future SETI Future SETI SpectrometersSpectrometers2015 4 THz 400 beams
10 GHz each2020 128 THz 12,800 beams
2025 4000 THz 40,000 beams
2030 128,000 THz 1M beams
Moore’s Law in FPGA Moore’s Law in FPGA worldworldComputational Density Comparison
1000
10000
100000
1000000
10000000
10/28/1995
3/11/1997
7/24/1998
12/6/1999
4/19/2001
9/1/2002 1/14/2004
Release Date
(MO
PS
/MH
z)*l
am
da^
2 Processor Peak
FPGA 32-bit int MAC
FPGA maximum sustained performance
1
10
100
1000
10000
100000
12/1/1996
6/19/1997
1/5/1998
7/24/1998
2/9/1999
8/28/1999
3/15/2000
10/1/2000
4/19/2001
11/5/2001
5/24/2002
Release date
MO
PS
(3
2 b
it M
AC
)
100X More efficient100X More efficientthan micro-processors!than micro-processors!
3X improvement3X improvementper year!per year!
Multi-Purpose FPGA-Multi-Purpose FPGA-Based Spectrometer Based Spectrometer (NSF, A. Parsons)(NSF, A. Parsons)
XilinxVirtex-II 6000
FPGA
XilinxVirtex-II
1000FPGA
256 MB DRAM
AreciboFeed
Array
200 MhzADC
Compact PCIBackplane
Software
200 MhzADC
200 MhzADC
200 MhzADC
I
I
Q
Q
Pol. 1
Pol. 2
{
{
200 Aux. I/O
SETI ApplicationsSETI Applications• ALFA Sky Survey (300 MHz x 7 beams)ALFA Sky Survey (300 MHz x 7 beams)
• Parkes Southern SERENDIPParkes Southern SERENDIP
• JPL/UCB/SI Survey (20 GHz Bandwidth)JPL/UCB/SI Survey (20 GHz Bandwidth)
• SETI Italia (Bologna)SETI Italia (Bologna)
• SETI@homeSETI@home
Astronomy ApplicationsAstronomy Applications• GALFA Spectrometer – Arecibo Multibeam Hydrogen SurveyGALFA Spectrometer – Arecibo Multibeam Hydrogen Survey
• Astronomy Signal Processor – ASP – Don Backer (pulsars)Astronomy Signal Processor – ASP – Don Backer (pulsars)
• ATA4 Correlator F Engine ATA4 Correlator F Engine
• Reionization Experiments (Backer (UCB), Chippendale/Ekers Reionization Experiments (Backer (UCB), Chippendale/Ekers (ATNF)) (ATNF))
Filter Response:PFB vs. FFT
Next Generation BoardNext Generation BoardBEE2 (2004/5) – Chen BEE2 (2004/5) – Chen ChangChang• 5 Xilinx XC2VP70 5 Xilinx XC2VP70
• 40 GB RAM (8 GB each chip, 13Gbit/sec/chip)40 GB RAM (8 GB each chip, 13Gbit/sec/chip)
• 18 10Gbit/sec infiniband ports18 10Gbit/sec infiniband ports
• 50 boards per rack, Tbit/sec infiniband switch50 boards per rack, Tbit/sec infiniband switch
• Applications:Applications:– 1 GHz, 1 Gchannel spectrometer (single board)1 GHz, 1 Gchannel spectrometer (single board)– Next Generation ATA backends (ata32 = 2 boards)Next Generation ATA backends (ata32 = 2 boards)– SKA imagingSKA imaging
B2 Module: board layoutB2 Module: board layout• 5 compute 5 compute
elements on a elements on a boardboard
• Up to 400 billion Up to 400 billion CMAC/s CMAC/s performanceperformance
• communication communication bandwidth: bandwidth:
– 240 Gbps on-240 Gbps on-board 360 board 360 Gbps off-boardGbps off-board
Global InterconnectsGlobal Interconnects• Commercial Infiniband Commercial Infiniband
switch from Mellanox, switch from Mellanox, Voltaire, etc.Voltaire, etc.– Packet switched, non-Packet switched, non-
blockingblocking
– 24 ~ 144 ports (4X) per 24 ~ 144 ports (4X) per chassischassis
– Up to 10,000 ports in a Up to 10,000 ports in a systemsystem
– 200~1000 ns switch latency200~1000 ns switch latency
– 400~1200 ns FPGA to FPGA 400~1200 ns FPGA to FPGA latencylatency
– 480Gbps ~ 2.88Tbps full 480Gbps ~ 2.88Tbps full duplex constant cross duplex constant cross section bandwidthsection bandwidth
– <$400 per port<$400 per port
ComputeNode
#N
ComputeNode
#1
Infiniband Crossbar Switch
Ethernet Switch
19” 48RU Rack Cabin 19” 48RU Rack Cabin CapacityCapacity
• 40 compute nodes in 5 chassis (8U) per 40 compute nodes in 5 chassis (8U) per rackrack
• Up to 16 trillion CMac/s performance per Up to 16 trillion CMac/s performance per rackrack
• 250 Watt AC/DC power supply to each 250 Watt AC/DC power supply to each bladeblade
• 12.5 Kwatt total power consumption12.5 Kwatt total power consumption
• Hardware cost: ~ $1MHardware cost: ~ $1M
Unified Digital Processing Unified Digital Processing ArchitectureArchitecture
• Distributed per antenna spectral channel processingDistributed per antenna spectral channel processing
• Multiple reconfigurable backend application Multiple reconfigurable backend application processingprocessing
• Commercial packet switched interconnectCommercial packet switched interconnect
PolyphaseFilter
Banks
ChannelReorderBuffer
Infin
iban
d S
wtic
h
XMAC imaging
Spectrometer
Pulsar SearchingB
eam
form
ing
PolyphaseFilter
Banks
ChannelReorderBuffer
An #1
An #N
Infin
iban
d
Sw
tich
Why you might not Why you might not want SETI want SETI experiments on the experiments on the SKA:SKA:
Desired SETI SKA Desired SETI SKA ParametersParameters• Wide bandwidth (0.1 to 35 GHz)Wide bandwidth (0.1 to 35 GHz)
• 1 M beams1 M beams
• Wide beams (primary and Wide beams (primary and synthesized)synthesized)
- compact array strongly preferred!!! - compact array strongly preferred!!!
(for both targetted and sky survey)(for both targetted and sky survey)
Seti Haiku
Searching for lifeSearching for lifeAnswers are revealedAnswers are revealedAbout ourselvesAbout ourselves
Paula Cook, Duke UniversityPaula Cook, Duke University
One million earthlingsOne million earthlingsBounded by optimismBounded by optimismLeave their PC’s onLeave their PC’s on
Dan SeidnerDan Seidner
Seti.org
Planetary.org
Seti.berkeley.edu