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AA-mid demonstrator. Dion Kant AAVP 2010 8 – 10 December 2010, Cambridge, UK. Outline. Project target Description of Work Project partnerships Current activities Evaluation results Conclusion. AA-mid (draft) key requirements. Requirements may still be adapted. - PowerPoint PPT Presentation
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AA-mid demonstrator
Dion Kant
AAVP 20108 – 10 December 2010, Cambridge, UK.
AA-mid 2 - GWK, 2010/12/10AAVP 2010
Outline
• Project target• Description of Work• Project partnerships• Current activities• Evaluation results• Conclusion
AA-mid 3 - GWK, 2010/12/10AAVP 2010
AA-mid (draft) key requirements
Physical collecting area ~2000 m^2Number of stations 10 to 15Polarisation Dual polarisationFrequency range 400 – 1450 MHzArchitecture Based on EMBRACET_sys 50K TargetDynamic range @ ADC 42 dBInstantaneous bandwidth ~250 MHzNumber of independent FoVs 2HPBW (FoV) 16 degrees @ 1 GHzStation output bandwidth 500 MHz
Requirements may still be adapted
AA-mid 4 - GWK, 2010/12/10AAVP 2010
AA-mid time line, phases and
• Full project (~2000 m^2 AA) not funded today• AAVS1 = first phase • Funding for design phase within AAVS1
– 2010 to 2013– Delivers design + small number of front end proto types– Use EMBRACE evaluation as input for design– Use EMBRACE platform as test-bed for new tile developments– New design based on EMBRACE
• Site selection will be decided on later• First testing will be performed at current EMBRACE stations• Second stage testing: Use Portugal site (SKA like environment)• Second phase (AAVS2) (beyond 2013) full roll-out AA-mid
demonstrator
AA-mid 5 - GWK, 2010/12/10AAVP 2010
Design approach
• Base new design on EMBRACE architecture and other demonstrators• Incremental approach
– Level 1 topics (should)– Level 2 topics (may)
• Main enhancements are (level 1 topics):– Introduce dual polarisation signal processing– Reduce power consumption per signal path– Improve tile control system– Reduce system noise– Second generation beam former chip (4-bit phase control)– Improve mechanical design, this includes housing & radome– Improve design for manufacturability
AA-mid 6 - GWK, 2010/12/10AAVP 2010
Design approach level 2 topics
• Investigate LNA above ground plane (integrated on feed board). Main goal is to be able to use FR4 for feed board (element cost reduction)
• Investigate balanced LNA approach• Improve station processing bandwidth
– Input bandwidth (250 MHz per channel)– Output bandwidth >2x250 MHz– As a fall back current EMBRACE
processing hardware will be used• Investigate non-continues
Unit/substation approach;• Obtain better EM model of tile to predict radiation pattern
including polarisation behavior. • ….
AA-mid 7 - GWK, 2010/12/10AAVP 2010 7
• XX “tiles” in a substation.• Every substation slightly tilted.• Substation closed by EPS wall en top.• Passive cooling by ground connection through poles.
• SKA station formed by multiple substations.• Walkable spaces between substations.• 56m diameter
288.000 antenna elements
Non-continues substations
AA-mid 8 - GWK, 2010/12/10AAVP 2010
Design approach level 2 topics
Topics to be solved :• Need software development partnership• Need correlator suitable for 15x2x1GS/s inputs• …
Can survive with current EMBRACE system in first phase of the project
AA-mid 9 - GWK, 2010/12/10AAVP 2010
Project partnerships
• Established members:– OPAR, France: Part of system design, beam former chip design,
EMBRACE evaluation;– ASTRON, the Netherlands: Part of system design, focus on level 1 front-
end topics, industrialisation and EMBRACE evaluation– …
• Members (becoming established):– Italy, INAF: Possible topics: Receiver, LO system, …– UK Several Institutes: Antenna design alternatives including electronic
integration and testing, Digital processing, …– Germany, MPIfR: Signal distribution and multiplexing, digital processing;– Portugal, Preparation for Portugal station roll out and site development– France, AD converter including poly phase filter bank integration– …
AA-mid 10 - GWK, 2010/12/10AAVP 2010
Current Activities and Progress
• First AAmid proto type tile underway
Octa boardsConnection boards
Center boardAluminum ground plane
AA-mid 11 - GWK, 2010/12/10AAVP 2010
Current Activities and Progress
• First AAmid proto type tile underway
Bottom view Octa concept
AA-mid 12 - GWK, 2010/12/10AAVP 2010
AAmid Octa Concept; 3D bottom view
Current Activities and Progress
AA-mid 13 - GWK, 2010/12/10AAVP 2010
Improved element mechanics
SKA Station Design
Multiple vivaldi antennas in one sheet
LNA close to pick-up point
Plastic support to keep tops in place
AA-mid 14 - GWK, 2010/12/10AAVP 2010
Aluminum Large Plates to decrease assembly time
SKA Station Design
Metal-Metal joining by clinching
Also expandable (connectable) in other
direction
AA-mid 15 - GWK, 2010/12/10AAVP 2010 15
• XX “tiles” in a substation.• Every substation slightly tilted.• Substation closed by EPS wall en top.• Passive cooling by ground connection through poles.
• SKA station formed by multiple substations.• Walkable spaces between substations.• 56m diameter
288.000 antenna elements
EM analysis of non-continues substations
AA-mid 16 - GWK, 2010/12/10AAVP 2010
EM analysis of non-continues substations
Vacuum formed “tile” bottom for
six modules(approx. 1.5 x 2m)
Placement in field by forklift or crane,
like LOFAR HBA.
AA-mid 17 - GWK, 2010/12/10AAVP 2010
Small tile: Simulate and measure
AA-mid 18 - GWK, 2010/12/10AAVP 2010
Good resemblance model and measurements
0.5 1 1.5-25
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Active reflection coefficients
AA-mid 19 - GWK, 2010/12/10AAVP 2010
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Good resemblance model and measurements
Measured and simulated phases
AA-mid 20 - GWK, 2010/12/10AAVP 2010
Current Activities and Progress
• EMBRACE Evaluation and test-bed development
AA-mid 21 - GWK, 2010/12/10AAVP 2010
Status Nançay Station
• ~ 62 m2 area 56 Tiles• 4032 Vivaldi elements (single linear polarisation)• Currently 48 tiles cabled up end-to-end• Grouped into tilesets of 4 tiles• 64 tiles to be installed by end 2010• Ultimately, 80 tiles in early 2011
Current Activities and Progress
AA-mid 22 - GWK, 2010/12/10AAVP 2010
Status Westerbork Station
• 64 Tiles, (~70 m^2)• 25 Tiles online in a 3x3 and 4x4 array configuration• Ultimately 144 Tiles (160 m^2) in 2011
Current Activities and Progress
AA-mid 23 - GWK, 2010/12/10AAVP 2010
Digital beam former details
AA-mid 24 - GWK, 2010/12/10AAVP 2010
Modified architecture to more generic one
• Full data rate can be exploited:• 2x62 Ebeamlets per CDO output; e.g.
two beams of 12 MHz each• Digital beam former software less
complex (can use Matrix formalism now)• Increased update rate digital beam
weights
AA-mid 25 - GWK, 2010/12/10AAVP 2010
EMBRACE station experiment objectives and results• Detection of GPS satellite signals• Scanned Beam Pattern on Afristar• Redundant base line experiments on Afristar• Solar Fringes and system noise verification• Fringes of Cas A and Cygnus• RECENT RESULT: Detection of pulsar
Current Activities and Progress
• Simultaneous detection of two pulsars within one FoV• Simultaneous detection of two widely separated pulsars
using independent FoVs• Detection of HI• Simultaneous detection of HI and pulsars• Beam swapping with beams on Cas A and Cygnus• Correlate with WSRT dish
• RECENT RESULT: Detection of pulsar
Plan
AA-mid 26 - GWK, 2010/12/10AAVP 2010
Drift scan of GPS satellite
• Strong carrier at 1227MHz• Subband statistics• Pointing offset between
tilesets
AA-mid 27 - GWK, 2010/12/10AAVP 2010
Early highlights: solar fringes
Interferometric measurement with 10 tiles two E-W ULAs frequency: 1179 MHz integration: 10 s bandwidth: 195 kHz
Initial performance est. A/T = 4.7·10-3 (to sun) Tsys = 103 – 117 K (to zenith)
AA-mid 28 - GWK, 2010/12/10AAVP 2010
Early highlights: instrument quality
• Redundant baselines produce redundant visibilities
Scanned Tile Beam pattern measured on Afristar satellite
Model Measurement
AA-mid 30 - GWK, 2010/12/10AAVP 2010
Fringes of Cas A!
• Experimental settings• 3x3 array• 1254 MHz• 30 s integration• 195 kHz bandwidth
• Initial conclusions• Confirms A/T• Correlation offsets
AA-mid 31 - GWK, 2010/12/10AAVP 2010
Pulsar detection Setup details
AA-mid 32 - GWK, 2010/12/10AAVP 2010
EMBRACE first pulsar result
AA-mid 33 - GWK, 2010/12/10AAVP 2010
Conclusion
• AA-mid is ramping up• EMBRACE Pulsar Detection demonstrates first L-
band AA detection ever! It demonstrates:• Complete data path and processing is under control• Hierarchical beam forming is working
• and much more to come
Thank you
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