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RFI Mitigation -- B. M. Lewis

An extensive review of mitigation techniques in radio astronomy was
written by Steve Ellingson for presentation at the ITU. This document
is now an ITU Report and a working document under the ITU question on
the mitigation of rfi for radio astronomy, a question adopted in the
past under Willem Baan's instigation. With the planned deployment of
a Dutch LOFAR instrument in The Netherlands, in an rfi-rich
environment, mitigation is essential if any astronomy is to be done
with it. Consequently there has been a lot of Dutch activity.

Many aspects of the Dutch work are contained in the thesis by Albert
Boonstra. The pdf version of this work is in the file
"its_boonstra.pdf" located at ftp://ftp2.naic.edu/pub/ast/murray/rfi

The overview on mitigation document is in the file "mitigation.pdf" in
the same area, while the literature the mitigation report references,
excluding only a couple of book texts, is in the file "ITU.pdf".

The general experience thusfar in mitigation, is that of order 30 dB
of suppression is possible fairly straight forwardly. But improving
on that is hard work, and robust, turnkey procedures are not yet
available.

An Arecibo exercise was conducted by Desh & Lewis. They sampled 1024
point spectra every millisecond in the Iridium Satellite band, and
looked at a robust statistics approach to mitigating the satellite
signal. This approach still only achieved about 30 dB of suppression,
which was set in this case by the accuracy with which hanning spectra
removes flip-flop noise: more might by obtained were that aspect to be
improved. This report can be found at
http://www.naic.edu/~blewis/draft_v4.pdf



ftp://ftp2.naic.edu/pub/ast/murray/rfi