Документ взят из кэша поисковой машины. Адрес оригинального документа : http://www.atnf.csiro.au/projects/askap/archive/SKA_Australian_strengths.doc Дата изменения: Thu Aug 12 04:12:28 1999 Дата индексирования: Sat Sep 6 21:27:55 2008 Кодировка: Поисковые слова: annular solar eclipse

Some High-Impact Australian SKA Contributions - P. Hall, 4 August 1999.



Site Studies

Australian sites have clear physical and terrestial RFI immunity
advantages; well-developed phase A project; strong links to WA state
government and local authorities. Comprehensive initial report just
produced. Certainly best-developed of international site studies. Will
need on-going resources to deal with more complex RFI monitoring and
prediction; EIS and related social impact issues; wider investigations
outside WA. Related "radio quiet zone" work requires strategic legal
thinking.


Integrated Antenna/RF/IF Systems

Good MMIC design and production links; currently very manpower limited.
Room to improve considerably on Dutch efforts to date (e.g. in eliminating
feeder transmission line structures, use of better balancing topologies,
implementation of high-dynamic range circuits). Possibly could extend to
hybrid integrated photonic interface - great interest in wider (e.g. 1 hT)
community. Proposal to provide a post-doc as Australian contribution to
NRAO Major Research Initiative proposal. MRI outcome known in ~ Nov. 99.

Interference Mitigation
Good leads in analog photonic and high-temperature superconductor filters.
Photonic is substantially original and first-round study is being done
under contract by Minasian et al at USyd. Longer-term funding required for
prototyping. CSIRO HTS filters look very good relative to international
attempts to date. Modest longer-term commitment needed to keep CTIP HTS
facility alive - but apparently depends on other factors as well as
finance.

New Software Radio Telescope project moving well. Links to supercomputing
centre at Swinburne. Good prospects, but need to keep moving - could
easily be overtaken by an intensive LOFAR effort. Powerful tool though for
SKA system design and to assess toxicity of interference mitigation
hardware and software on actual astronomical data. (We seem to have a lead
in this thinking).

Post-correlation processing. Aperture and focal plane studies. Moving,
but severely manpower limited. Good prospects, with Bob Sault moving to
SKA arena.


Antennas and Arrays

Strengths in treating antennas as part of system; in producing competitive
preliminary designs for elements and topologies; in appreciating science
limitations of various technologies. Excellent analysis and simulation
tools. Possibilities in terms of integrated systems (MMICs etc), photonic
beamforming. Manpower limited - requirements in areas such as (spherical)
lens antenna design, array hierarchies and beamforming.


Configurations and Imaging

Strong CSIRO theoretical and applied background; direct links to next-
generation processing simulation environment (AIPS++). Experience in
operating a highly-flexible synthesis instrument (ATCA) pushing boundaries
of current practice (on-line imaging, high dynamic range mosaicing etc).
Strong Australian cm-wave astronomy community.

Signal Processing
Many possibilities; strong ATNF and CTIP technology base (inc. custom and
semi-custom devices). Well-known for innovative correlator and associated-
system design. Feasible extension into adaptive interference cancellers
and wideband tuneable notch filters. Strong interest in fast photonic
ADCs. New CTIP 'smart antennas' project highly relevant. Interest and
track record in innovative signal processing applications. Good knowledge
of marketplace and relevant trends.


System Studies
We are comparatively strong in linking science to overall system design -
maintaining flexibility, but ending up with sensible compromises in costly
areas. Obviously a good attribute in areas like SKA beamforming.

What about producing (soon) some representative (strawmen) SKA system
topologies?..haven't seen any so far, and the world needs them badly to
guide thinking in terms of flexibility-complexity tradeoffs etc. More
generally, this preliminary 'system definition' would be an excellent
complement to the science case.


Intermediate Timescale Demonstrator
What about a small-scale demonstrator linking aspects of the antenna,
array, integrated RF, and DSP, functions? Perhaps via an extended smart
antenna project. Could have strong system links to interference mitigation
(and related concerns), imaging etc. Complete on timescale of <3 years and
shape as lead-in to astronomical prototype in the next triennium?


SKA Astronomical Prototype
We have obvious skills in building and operating telescopes. A 2000 m2
collecting area at least doubles the sensitivity of the ATCA, in addition
to any SKA project contributions. Recall discussion relating to focussed
vs strategic thinking, and advantages of a 'label' in the Australian SKA
effort. The prototype would need to be defined in the coming 3-4 year
period. Actual system definition could be left until late in the piece;
gain most of the political advantages with only a general concept floated
soon.
(For a first suggestion, see John Bunton doublet proposal of today).