Introduction
Italian IRA-INAF proposes a re-instrumentation of a part (Effective
area=8000m2) of the Northern Cross radiotelescope aimed at obtaining
a large test bed, based on cylindrical antennas, to develop new
technology and algorithms for the Square Kilometre Array (SKA)
project.
The BEST test-bench provides valuable experience in the design of low-cost
receivers, analog and digital beam forming, multibeaming, RFI
mitigation with a large collecting area and high sensitivity, data
transmission via optical fibre and correlation imaging of wide
field-of-view
techniques. The Northern Cross radiotelescope (Medicina, Italy) is a
very suitable SKA work bench that could allow the investigation of
many crucial points of the project definition.
The Northern Cross T-shaped radiotelescope
The Northern Cross T-shaped radiotelescope is one of the largest
transit instruments in the northern hemisphere. It is composed of two
arms: the E/W and the N/S one.
The E/W (35 x 564 m) is a large single cylindrical reflector
equipped with 1536 dipoles. The N/S array is composed by 64 (24 x 7.5
m) cylindrical reflectors with 64 dipoles each (8 dipoles x 8 blocks),
for a total of 4096 dipoles.
By installing new low-cost / low noise front ends, the system
temperature could be drastically reduced opening up many investigation
in the low frequency radioastronomy field and, in addition, to the
mentioned experiences for SKA design and construction.
BEST - Basic Element for Ska Training
This Italian demonstrator is named BEST (Basic Element for SKA
Training) and it will be built in successive steps, with increasing
dimensions exploiting the N/S arm reflectors:
- The first step, named BEST-1, foresees 4 receivers installed on a
single cylindrical reflector.
- The second step, named BEST-2, foresees 32 receivers installed on
8 reflectors.
- The third step, named BEST-3, foresees 192 receivers installed on
48 cylindrical reflectors and from a minimum of 6 to a maximum of 24
receivers in the East-West arm.
BEST specifications
| Frequency: |
400 – 416 MHz |
| Polarisation: |
Single Linear |
| Scan Volume: |
+/- 45 deg. from zenith and +/- 3.5 deg from the meridian |
| No of indep. FOV: |
1 (15 squadre deg.) |
| Tsys: |
90 deg K @ 408 MHz |
| Ant. element phase control: |
6 bit |
| Instant. Bandwidth: |
16 MHz |
| No of digitally independent beams: |
BEST-1: 3
BEST-2: 21
BEST-3: >400 (potential) |
More:
Video on line
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