Interference Mitigation Tests at Molonglo Daniel Mitchell, Duncan CampbellWilson, Frank Briggs

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Interference Mitigation Tests at MolongloDaniel
Mitchell, Duncan Campbell-Wilson, Frank Briggs
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Overview

• RFI mitigation is likely to play an important
  role in SKAMP data processing.
• The wide bandwidth alone will open the telescope
  up to a much greater level of RFI.
• Have done some short, preliminary observations
  with and without RFI to see how effective
  mitigation is likely to be.

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Preliminary RFI Tests.

• MOST has 88 bays (antennas), which will be
  cross-correlated with all of the others
• 88 input correlator.
• Correlator will have 96 inputs
• Room for RFI reference antennas.
• Use closure relation based "post-correlation"
  cancellation algorithm to test RFI reduction.

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RFI Test Range

• RFI - Broad-band noise from the RFI site
• Estimated 5000 computer equivalents
• Telemetry link to transmitter, variable
  attenuator white noise source
• 4 IFs Sampler box
• Two 778m x 12m MOST arms (with bay masking)
• Two orthogonal polarisations from the 6m dish
• Record to a PC at 16 Msamples / second / IF

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Short Baselines (bays E01 W01)
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Short Baselines (bays E01 W01)
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Short Baselines (bays E01 W01)
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Short Baselines (bays E01 W01)
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Short Baselines (bays E01 W01)
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Short Baselines (bays E01 W01)
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Medium Baselines (bays E22 W22)
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Medium Baselines (bays E22 W22)
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Medium Baselines (bays E22 W22)
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Long Baselines (bays E44 W44)
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Long Baselines (bays E01 W01)
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Long Baselines (bays E01 W01)
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Summary

• RFI mitigation is likely to play an important
  role in SKAMP data processing.
• The wide bandwidth alone will open the telescope
  up to a much greater level of RFI.
• A preliminary look at cancelling RFI from single
  bay cross-correlations seemed to work well on
  three baseline scales.