Transcript Diapositiva 1 - Square Kilometre Array

S.Montebugnoli,
G.Bianchi, J. Monari, G. Naldi, F. Perini, M.Schiaffino
SKADS Medicina tech. Staff
INAF-IRA (I)
SKA- Limelette Nov. 2009
S. Montebugnoli
BEST is a test bed for the development of new technology
for SKADS, obtained by the refitting of a subset
of the 5632 dipoles available on the 564x 640 mt
Cross telescope
SKA-Limelette Nov. 2009
S. Montebugnoli
Analogue and/or digital optical links
Basing on the reliability prediction, an analogue link was used to directly
transport the RF from the front end to the receiver room . Phase and
amplitude stability demonstrated that it is possible to calibrate an array and
talk of Valeria Scarano later on
work with it.
See poster of Federico Perini
From
Ant.
Opt.
TX
Analogue opt. link
Opt.
RX
IF
To data
acquisition
OL
Front-End
SKA-Limelette Nov. 2009
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• Architecture and technology of BEST
demonstrator .
SKA-Limelette Nov. 2009
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BEST-2:
• 32 Rx @ 408 MHz
• Tsys  90 K
• Bw = 16 MHz
• Ac= 1400 sqm
• One Pol.
• 8 (24x7 m) cylinders
• 21 beams
4 Rx
Each
Cylin.
• it will be used on the SKADS
DtE (Jive) UHF tests
Front End
IF
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•.... availability of easily replicable electronic
Front end & Opt. TX
IF stages
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• Local oscillator and sync distribution in large
infrastructure and array
Clock Distributor
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LO distributor
Board Meeting Limelette Nov. 2009
SKA-Limelette Nov. 2009
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BEST-3
The BEST-3 (on the E/W arm) is an 800 sqm low frequency test bed in
the 120-240 MHz band. It is a valuable bridge toward the AAlo (BEST-3lo)
SKADS
PrepSKA
BEST-3lo
(technological
bridge)
BEST-2
AAlo
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S. Montebugnoli
BEST-3lo
SKA-Limelette Nov. 2009
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BEST-3lo
RS 485
RS 485
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BEST-3lo technology
BEST-3lo: Front end & optical TX
IF BEST-3lo prototype boards
mounted into a rack.
SKA-Limelette Nov. 2009
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The practical system installed on the E/W focal line
(2 Rx, 1 remote control board, 2 TX and pne power supply)
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BEST-3lo technology
two BEST-3lo receivers
assembly
SKA-Limelette Nov. 2009
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•Wide Band and high dynamic range Data
Acquisition system (BEST-2 and BEST-3lo)
BEST-3lo
BEST-2
BERKELEY
CASPER
Ibob & Bee2
(in future Roach)
SKA-Limelette Nov. 2009
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Ibobs / BEE2 Data acquisition for both
medium & low frequency
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First observation of Virgo A with BEST-2
data was sent to the CASPER group in Berkeley
- Aaron Parsons (UC Berkeley)
- Jason Manley Cape Town University
SKA-Limelette Nov. 2009
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•MVDR adaptive beamforming.
METHOD
MVDR
TIME required
(3 GHz clock
PC)
9.313 sec
Applicability
in a static
environment
Good
Applicability
in a dynamic
environment
Good
FD-LCMV
54.53 sec
Very Good
Not
Applicable
NULL
9.125 sec
STEERING
Good
Good
KLT
Good
Good
9.031 sec
MVDR for BEST-2
SKA-Limelette Nov. 2009
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•.....tested adaptive beamforming and
RFI mitigation algorithms on the Ibob.
system
Two rx basic Implementation of a beamformingCASPER
on the Ibob
(Ibob)
i.e coefficients from
the previous MVDR
algorithms
SKA-Limelette Nov. 2009
S. Montebugnoli
FPAs for cylinders in terms of performance
and cost-effectiveness
FoW Analysis on the E/W arm
The effect of a Focal Plane Array has been
simulated using an equivalent aperture field
distribution in a 2D full-wave electromagnetic
model
-
±10° Scan Angle in the H-plane can be achieved with more than 60% efficiency
Antenna Efficiency
5000
4000
4000
Feed displacement along y (mm)
Feed displacement along y (mm)
Max Position (Deg)
5000
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1000
0
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0
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2000
Feed displacement along x (mm)
4000
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-6000
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-2000
0
2000
4000
Feed displacement along x (mm)
6000
S. Montebugnoli
The BEST-2 and BEST-3lo represent a ready platform
that allows, from now on, to face the development of
good performance, replicable electronic and prove
some concepts for the next AAlo step.
SKA-Limelette Nov. 2009
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Limelette Nov. 2009
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FIRST FRINGE (NOV 4 ,2009)
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•Simulation Software for sensor array
Comparison between the Cassiopeia A observed
fringes and the simulated one (BEST).
Limelette Nov. 2009
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BEST-3lo ……yesterday first fringes on Cas A
In the band 138-142 MHz
NOT ARRIVED IN TIME (via E-MAIL from Medicina ) FOR
THE PRESENTATION
Limelette Nov. 2009
S. Montebugnoli
•Tested adaptive beamforming and
RFI mitigation algorithms
Different methods have been investigated, using
the BEST-1 demonstrator, as the MSC (Multiple
Sidelobe Canceller).
Proc.
A
D
Limelette Nov. 2009
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Block diagram of the FX correlator implemented (J. Manley)
on the Bee2 cluster (BEST-2)
Limelette Nov. 2009
S. Montebugnoli