The low-frequency environment of the Murchison Widefield Array: radio-frequency interference analysis and mitigation

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

doi:10.1017/pasa.2015.7

The low-frequency environment of the Murchison Widefield Array: radio-frequency interference analysis and mitigation

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

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Abstract

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

Original language	English
Article number	e008
Number of pages	13
Journal	Publications of the Astronomical Society of Australia
Volume	32
DOIs	https://doi.org/10.1017/pasa.2015.7
Publication status	Published - 16 Jan 2015

Keywords

astro-ph.IM

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10.1017/pasa.2015.7

Accepted ManuscriptAccepted author manuscript, 1.76 MB

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Offringa, A. R., Wayth, R. B., Hurley-Walker, N., Kaplan, D. L., Barry, N., Beardsley, A. P., Bell, M. E., Bernardi, G., Bowman, J. D., Briggs, F., Callingham, J. R., Cappallo, R. J., Carroll, P., Deshpande, A. A., Dillon, J. S., Dwarakanath, K. S., Ewall-Wice, A., Feng, L., For, B. .-Q., ... Zheng, Q. (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 e008. https://doi.org/10.1017/pasa.2015.7

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title = "The low-frequency environment of the Murchison Widefield Array: radio-frequency interference analysis and mitigation",

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

keywords = "astro-ph.IM",

author = "Offringa, {A. R.} and Wayth, {R. B.} and N. Hurley-Walker and Kaplan, {D. L.} and N. Barry and Beardsley, {A. P.} and Bell, {M. E.} and G. Bernardi and Bowman, {J. D.} and F. Briggs and Callingham, {J. R.} and Cappallo, {R. J.} and P. Carroll and Deshpande, {A. A.} and Dillon, {J. S.} and Dwarakanath, {K. S.} and A. Ewall-Wice and L. Feng and For, {B. -Q.} and Gaensler, {B. M.} and Greenhill, {L. J.} and P. Hancock and Hazelton, {B. J.} and Hewitt, {J. N.} and L. Hindson and Jacobs, {D. C.} and M. Johnston-Hollitt and Kapi{\'n}ska, {A. D.} and Kim, {H. -S.} and P. Kittiwisit and E. Lenc and J. Line and A. Loeb and Lonsdale, {C. J.} and B. McKinley and McWhirter, {S. R.} and Mitchell, {D. A.} and Morales, {M. F.} and E. Morgan and J. Morgan and Neben, {A. R.} and D. Oberoi and Ord, {S. M.} and S. Paul and B. Pindor and Pober, {J. C.} and T. Prabu and P. Procopio and J. Riding and Shankar, {N. Udaya} and S. Sethi and Srivani, {K. S.} and L. Staveley-Smith and R. Subrahmanyan and Sullivan, {I. S.} and M. Tegmark and N. Thyagarajan and Tingay, {S. J.} and Trott, {C. M.} and Webster, {R. L.} and A. Williams and Williams, {C. L.} and C. Wu and Wyithe, {J. S.} and Q. Zheng",

note = "This is the Accepted Manuscript version of the following article: A. R. Offringa, et al., “The low-frequency environment of the Murchison Widefield Array: radio-frequency interference analysis and mitigation”, Publications of the Astronomical Society of Australia, Vol. 32, March 2015. The final published version is available at: https://doi.org/10.1017/pasa.2015.7 {\textcopyright} Astronomical Society of Australia 2015 ",

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doi = "10.1017/pasa.2015.7",

language = "English",

volume = "32",

journal = "Publications of the Astronomical Society of Australia",

issn = "1323-3580",

publisher = "Cambridge University Press",

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Offringa, AR, Wayth, RB, Hurley-Walker, N, Kaplan, DL, Barry, N, Beardsley, AP, Bell, ME, Bernardi, G, Bowman, JD, Briggs, F, Callingham, JR, Cappallo, RJ, Carroll, P, Deshpande, AA, Dillon, JS, Dwarakanath, KS, Ewall-Wice, A, Feng, L, For, B-Q, Gaensler, BM, Greenhill, LJ, Hancock, P, Hazelton, BJ, Hewitt, JN, Hindson, L, Jacobs, DC, Johnston-Hollitt, M, Kapińska, AD, Kim, H-S, Kittiwisit, P, Lenc, E, Line, J, Loeb, A, Lonsdale, CJ, McKinley, B, McWhirter, SR, Mitchell, DA, Morales, MF, Morgan, E, Morgan, J, Neben, AR, Oberoi, D, Ord, SM, Paul, S, Pindor, B, Pober, JC, Prabu, T, Procopio, P, Riding, J, Shankar, NU, Sethi, S, Srivani, KS, Staveley-Smith, L, Subrahmanyan, R, Sullivan, IS, Tegmark, M, Thyagarajan, N, Tingay, SJ, Trott, CM, Webster, RL, Williams, A, Williams, CL, Wu, C, Wyithe, JS & Zheng, Q 2015, 'The low-frequency environment of the Murchison Widefield Array: radio-frequency interference analysis and mitigation', Publications of the Astronomical Society of Australia, vol. 32, e008. https://doi.org/10.1017/pasa.2015.7

TY - JOUR

T1 - The low-frequency environment of the Murchison Widefield Array

T2 - radio-frequency interference analysis and mitigation

AU - Offringa, A. R.

AU - Wayth, R. B.

AU - Hurley-Walker, N.

AU - Kaplan, D. L.

AU - Barry, N.

AU - Beardsley, A. P.

AU - Bell, M. E.

AU - Bernardi, G.

AU - Bowman, J. D.

AU - Briggs, F.

AU - Callingham, J. R.

AU - Cappallo, R. J.

AU - Carroll, P.

AU - Deshpande, A. A.

AU - Dillon, J. S.

AU - Dwarakanath, K. S.

AU - Ewall-Wice, A.

AU - Feng, L.

AU - For, B. -Q.

AU - Gaensler, B. M.

AU - Greenhill, L. J.

AU - Hancock, P.

AU - Hazelton, B. J.

AU - Hewitt, J. N.

AU - Hindson, L.

AU - Jacobs, D. C.

AU - Johnston-Hollitt, M.

AU - Kapińska, A. D.

AU - Kim, H. -S.

AU - Kittiwisit, P.

AU - Lenc, E.

AU - Line, J.

AU - Loeb, A.

AU - Lonsdale, C. J.

AU - McKinley, B.

AU - McWhirter, S. R.

AU - Mitchell, D. A.

AU - Morales, M. F.

AU - Morgan, E.

AU - Morgan, J.

AU - Neben, A. R.

AU - Oberoi, D.

AU - Ord, S. M.

AU - Paul, S.

AU - Pindor, B.

AU - Pober, J. C.

AU - Prabu, T.

AU - Procopio, P.

AU - Riding, J.

AU - Shankar, N. Udaya

AU - Sethi, S.

AU - Srivani, K. S.

AU - Staveley-Smith, L.

AU - Subrahmanyan, R.

AU - Sullivan, I. S.

AU - Tegmark, M.

AU - Thyagarajan, N.

AU - Tingay, S. J.

AU - Trott, C. M.

AU - Webster, R. L.

AU - Williams, A.

AU - Williams, C. L.

AU - Wu, C.

AU - Wyithe, J. S.

AU - Zheng, Q.

N1 - This is the Accepted Manuscript version of the following article: A. R. Offringa, et al., “The low-frequency environment of the Murchison Widefield Array: radio-frequency interference analysis and mitigation”, Publications of the Astronomical Society of Australia, Vol. 32, March 2015. The final published version is available at: https://doi.org/10.1017/pasa.2015.7 © Astronomical Society of Australia 2015

PY - 2015/1/16

Y1 - 2015/1/16

N2 - The Murchison Widefield Array (MWA) is a new low-frequency interferometric radio telescope built in Western Australia at one of the locations of the future Square Kilometre Array (SKA). We describe the automated radio-frequency interference (RFI) detection strategy implemented for the MWA, which is based on the AOFlagger platform, and present 72-231-MHz RFI statistics from 10 observing nights. RFI detection removes 1.1% of the data. RFI from digital TV (DTV) is observed 3% of the time due to occasional ionospheric or atmospheric propagation. After RFI detection and excision, almost all data can be calibrated and imaged without further RFI mitigation efforts, including observations within the FM and DTV bands. The results are compared to a previously published Low-Frequency Array (LOFAR) RFI survey. The remote location of the MWA results in a substantially cleaner RFI environment compared to LOFAR's radio environment, but adequate detection of RFI is still required before data can be analysed. We include specific recommendations designed to make the SKA more robust to RFI, including: the availability of sufficient computing power for RFI detection; accounting for RFI in the receiver design; a smooth band-pass response; and the capability of RFI detection at high time and frequency resolution (second and kHz-scale respectively).

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

KW - astro-ph.IM

U2 - 10.1017/pasa.2015.7

DO - 10.1017/pasa.2015.7

M3 - Article

SN - 1323-3580

VL - 32

JO - Publications of the Astronomical Society of Australia

JF - Publications of the Astronomical Society of Australia

M1 - e008

ER -

The low-frequency environment of the Murchison Widefield Array: radio-frequency interference analysis and mitigation

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