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The Low-Frequency Environment of the Murchison Widefield Array: Radio-Frequency Interference Analysis and Mitigation

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Authors
Offringa, A.
Wayth, Randall
Hurley-Walker, N.
Kaplan, D.
Barry, N.
Beardsley, A.
Bell, M.
Bernardi, G.
Bowman, J.
Briggs, F.
Callingham, J.
Cappallo, R.
Carroll, P.
Deshpande, A.
Dillon, J.
Dwarakanath, K.
Ewall-Wice, A.
Feng, L.
For, B.
Gaensler, B.
Greenhill, L.
Hancock, P.
Hazelton, B.
Hewitt, J.
Hindson, L.
Jacobs, D.
Johnston-Hollitt, M.
Kapinska, A.
Kim, H.
Kittiwisit, P.
Lenc, E.
Line, J.
Loeb, A.
Lonsdale, C.
McKinley, B.
McWhirter, S.
Mitchell, D.
Morales, M.
Morgan, E.
Morgan, J.
Neben, A.
Oberoi, D.
Ord, Stephen
Paul, S.
Pindor, B.
Pober, J.
Prabu, T.
Procopio, P.
Riding, J.
Shankar, N.
Sethi, S.
Srivani, K.
Staveley-Smith, L.
Subrahmanyan, R.
Sullivan, I.
Tegmark, M.
Thyagarajan, N.
Tingay, Steven
Trott, C.
Webster, R.
Williams, A.
Williams, C.
Wu, C.
Wyithe, J.
Zheng, Q.
Date
2015
Type
Journal Article

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Citation
Offringa, A. and Wayth, R. and Hurley-Walker, N. and Kaplan, D. and Barry, N. and Beardsley, A. and Bell, M. et al. 2015. The Low-Frequency Environment of the Murchison Widefield Array: Radio-Frequency Interference Analysis and Mitigation. Publications of the Astronomical Society of Australia. 32: Article ID e008.
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PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF AUSTRALIA
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Department of Electrical and Computer Engineering
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Abstract

The Murchison Widefield Array is a new low-frequency interferometric radio telescope built in Western Australia at one of the locations of the future Square Kilometre Array. We describe the automated radio-frequency interference detection strategy implemented for the Murchison Widefield Array, which is based on the aoflagger platform, and present 72–231 MHz radio-frequency interference statistics from 10 observing nights. Radio-frequency interference detection removes 1.1% of the data. Radio-frequency interference from digital TV is observed 3% of the time due to occasional ionospheric or atmospheric propagation. After radio-frequency interference detection and excision, almost all data can be calibrated and imaged without further radio-frequency interference mitigation efforts, including observations within the FM and digital TV bands. The results are compared to a previously published Low-Frequency Array radio-frequency interference survey. The remote location of the Murchison Widefield Array results in a substantially cleaner radio-frequency interference environment compared to Low-Frequency Array’s radio environment, but adequate detection of radio-frequency interference is still required before data can be analysed. We include specific recommendations designed to make the Square Kilometre Array more robust to radio-frequency interference, including: the availability of sufficient computing power for radio-frequency interference detection; accounting for radio-frequency interference in the receiver design; a smooth band-pass response; and the capability of radio-frequency interference detection at high time and frequency resolution (second and kHz-scale respectively).