Spatial filtering experiment with the ASKAP beta array

Hellbourg, Grégory; Bannister, K. W.; HotarP, Aidan

doi:10.1109/rfint.2016.7833528

Cited by 14 publications

(11 citation statements)

References 15 publications

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“…Indeed, the ASKAP Boolardy Engineering Test Array (BETA) was used to test one of these RFI mitigation methodologies, a spatial filtering technique based on projecting out the interferer signature (Hellbourg et al 2012). This test demonstrated the effectiveness of the projection algorithm in suppressing RFI contamination in ASKAP PAF data (Hellbourg, Bannister, & Hotarn 2016). This success encouraged us to attempt a similar technique for the MPIPAF data taken at the Parkes site.…”

Section: Resultsmentioning

confidence: 79%

Spectral-Line Observations Using a Phased Array Feed on the Parkes Telescope

Reynolds¹,

Rhee²,

Westmeier³

et al. 2017

Publ. Astron. Soc. Aust.

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We present first results from pilot observations using a phased array feed (PAF) mounted on the Parkes 64-m radio telescope. The observations presented here cover a frequency range from 1150 to 1480 MHz and are used to show the ability of PAFs to suppress standing wave problems by a factor of ∼ 10 which afflict normal feeds. We also compare our results with previous HIPASS observations and with previous H i images of the Large Magellanic Cloud. Drift scan observations of the GAMA G23 field resulted in direct H i detections at z = 0.0043 and z = 0.0055 of HIPASS galaxies J2242-30 and J2309-30. Our new measurements generally agree with archival data in spectral shape and flux density, with small differences being due to differing beam patterns. We also detect signal in the stacked H i data of 1094 individually undetected galaxies in the GAMA G23 field in the redshift range 0.05 ≤ z ≤ 0.075. Finally, we use the low standing wave ripple and wide bandwidth of the PAF to set a 3σ upper limit to any positronium recombination line emission from the Galactic Centre of < 0.09 K, corresponding to a recombination rate of < 3.0 × 10 45 s −1 .

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Section: Resultsmentioning

confidence: 79%

Spectral-Line Observations Using a Phased Array Feed on the Parkes Telescope

Reynolds¹,

Rhee²,

Westmeier³

et al. 2017

Publ. Astron. Soc. Aust.

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show abstract

“…In future, adaptive beamforming could be used as a form of RFI mitigation on ASKAP, by placing nulls at the locations of transmitting satellites (Black et al 2015;Hellbourg et al 2014Hellbourg et al , 2016. This would involve changing the beams during an observation, which would need main-beam constraints and corrections for pattern rumble bias (Jeffs et al 2008) to avoid invalidating array calibration solutions.…”

Section: Radio-frequency Interferencementioning

confidence: 99%

“…Beyond teaching us how to improve ASKAP's system design, BETA contributed to astrophysical research (e.g., Serra et al 2015b;Harvey-Smith et al 2016;Hobbs et al 2016;Heywood et al 2016;Allison et al 2017;Moss et al 2017) including the discovery of neutral hydrogen in a young radio galaxy at redshift z = 0.44 through an absorption line search (Allison et al 2015). BETA also demonstrated real-time spatial radio-frequency interference (RFI) mitigation (Hellbourg, Bannister, & Hotan 2016).…”

Section: Introductionmentioning

confidence: 99%

Australian square kilometre array pathfinder: I. system description

Hotan

Bunton

Chippendale

et al. 2021

Publ. Astron. Soc. Aust.

235

159

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In this paper, we describe the system design and capabilities of the Australian Square Kilometre Array Pathfinder (ASKAP) radio telescope at the conclusion of its construction project and commencement of science operations. ASKAP is one of the first radio telescopes to deploy phased array feed (PAF) technology on a large scale, giving it an instantaneous field of view that covers $31\,\textrm{deg}^{2}$ at $800\,\textrm{MHz}$ . As a two-dimensional array of 36 $\times$ 12 m antennas, with baselines ranging from 22 m to 6 km, ASKAP also has excellent snapshot imaging capability and 10 arcsec resolution. This, combined with 288 MHz of instantaneous bandwidth and a unique third axis of rotation on each antenna, gives ASKAP the capability to create high dynamic range images of large sky areas very quickly. It is an excellent telescope for surveys between 700 and $1800\,\textrm{MHz}$ and is expected to facilitate great advances in our understanding of galaxy formation, cosmology, and radio transients while opening new parameter space for discovery of the unknown.

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“…Corrupted time-frequency data flagging and blanking is usually a necessary first data pre-processing stage, either achieved automatically based on varying statistical properties of the data, or manually after an expert visual inspection of the data. Spatial filtering methods are emerging as promising solutions for the recovery of uncorrupted timefrequency data when the system architecture permits their implementation [26]. RFI mitigation never comes at zero cost; it affects the achievable sensitivity of the telescope due to the loss of data, the operational cost when additional equipment is necessary, and the accuracy of the instrumental calibration.…”

Section: Active Rfi Mitigationmentioning

confidence: 99%

Cyclic Imaging for All-Sky Interference Forecasting with Array Radio Telescopes

Hellbourg,

Morrison

2020

Preprint

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Radio Frequency Interference (RFI) is threatening modern radio astronomy. A classic approach to mitigate its impact on astronomical data involves discarding the corrupted time and frequency data samples through a process called flagging and blanking. We propose the exploitation of the cyclostationary properties of the RFI signals to reliably detect and predict their locations within an array radio telescope field-of-view, and dynamically schedule the astronomical observations such as to minimize the probability of RFI data corruption.

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Spatial filtering experiment with the ASKAP beta array

Cited by 14 publications

References 15 publications

Spectral-Line Observations Using a Phased Array Feed on the Parkes Telescope

Spectral-Line Observations Using a Phased Array Feed on the Parkes Telescope

Australian square kilometre array pathfinder: I. system description

Cyclic Imaging for All-Sky Interference Forecasting with Array Radio Telescopes

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