Characterization of a dense aperture array for radio astronomy

Torchinsky, S.; Olofsson, A. O. H.; Censier, B.; Karastergiou, A.; Serylak, M.; Picard, Philippe; Renaud, Patrice; Taffoureau, C.

doi:10.1051/0004-6361/201526706

Cited by 13 publications

(9 citation statements)

References 22 publications

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“…The PAON4 antennas are installed near the EMBRACE prototype (Torchinsky et al 2016), and could therefore be easily connected to the electric mains and Ethernet network. At this place, the ground is particularly loose and in order to avoid having to build expensive and fixed concrete foundations, the antenna structures are slightly flexible with respect to horizontal stability, and are equipped with four legs in a statically undetermined configuration.…”

Section: Reflectors and Feed Designmentioning

confidence: 99%

“…FFT beam-forming is also possible using a regular grid of antenna, including dishes, as mentioned by (Tegmark & Zaldarriaga 2009). Such a strategy has already been implemented on a modest scale in individual LOFAR stations for the High Band Array, and at ∼ 1 GHz frequencies in EMBRACE (Torchinsky et al 2016). This was the ultimate goal of the SKA mid frequency array with an early demonstrator called 2-PAD (Armstrong et al 2009).…”

Section: Introductionmentioning

confidence: 99%

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Design, operation and performance of the PAON4 prototype transit interferometer

Ansari

Campagne

Charlet

et al. 2020

Monthly Notices of the Royal Astronomical Society

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PAON4 is an L-band (1250-1500 MHz) small interferometer operating in transit mode deployed at the Nançay observatory in France, designed as a prototype instrument for Intensity Mapping. It features four 5 meter diameter dishes in a compact triangular configuration, with a total geometric collecting area of ∼ 75m 2 , and equipped with dual polarisation receivers. A total of 36 visibilities are computed from the 8 independent RF signals by the software correlator over the full 250 MHz RF band. The array operates in transit mode, with the dishes pointed toward a fixed declination, while the sky drifts in front of the instrument. Sky maps for each frequency channel are then reconstructed by combining the time-dependent visibilities from the different baselines observed at different declinations. This paper presents an overview of the PAON4 instrument design and goals, as a prototype for dish arrays to map the Large Scale Structure in radio, using intensity mapping of the atomic hydrogen 21 cm line. We have operated PAON4 over several years and we have used data from observations in different periods to assess the array performances. We present preliminary analysis of a large fraction of this data and discuss crucial issues for this type of instrument, such as the calibration strategy, instrument response stability and noise behaviour.

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Section: Reflectors and Feed Designmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Design, operation and performance of the PAON4 prototype transit interferometer

Ansari

Campagne

Charlet

et al. 2020

Monthly Notices of the Royal Astronomical Society

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“…Various small-scale engineering systems have shown good results [6], and most recently the EMBRACE system has demonstrated that a large-scale aperture array system capable of making competitive astronomical measurements is now within reach [7,8]. What is absolutely clear is that so long as data sampling and processing costs continues to fall, the construction of a scientifically productive large aperture array operating at GHz frequencies becomes more of a question of not if, but when.…”

Section: Seti and Aperture Arraysmentioning

confidence: 99%

All-sky radio SETI

Garrett

Siemion²,

Vancapellen³

2018

Proceedings of MeerKAT Science: On the Pathway to the SKA — PoS(MeerKAT2016)

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Over the last decade, Aperture Arrays (AA) have successfully replaced parabolic dishes as the technology of choice at low radio frequencies -good examples are the MWA, LWA and LOFAR. Aperture Array based telescopes present several advantages, including sensitivity to the sky over a very wide field-of-view. As digital and data processing systems continue to advance, an all-sky capability is set to emerge, even at GHz frequencies. We argue that assuming SETI events are both rare and transitory in nature, an instrument with a large field-of-view, operating around the so-called "water-hole" (~ 1-2 GHz), might offer several advantages over contemporary searches. Sir Arthur C. Clarke was the first to recognise the potential importance of an "all-sky" radio SETI capability, as presented in his book, Imperial Earth. As part of the global SKA (Square Kilometre Array) project, a Mid-Frequency Aperture Array (MFAA) prototype known as MANTIS (Mid-Frequency Aperture Array Transient and Intensity-Mapping System) is now being considered as a precursor for SKA-2. MANTIS can be seen as a first step towards an "all-sky" radio SETI capability at GHz frequencies. This development has the potential to transform the field of SETI research, in addition to several other scientific programmes.

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“…To experiment with all these concepts, an ongoing case study has been conducted on the Electronic Multi-Beam Radio Astronomy Concept (EMBRACE) radio telescope facility at Nançay Observatory (see Figure 4.a and (Torchinsky et al, 2016)). The objective of the experiment is to evaluate the RFI mitigation strategy in terms of hardware complexity, detection efficiency and additional RFI metadata datarate cost.…”

Section: Fig 2 Spectrummentioning

confidence: 99%

“…EMBRACE is a phased-array radio telescope (Torchinsky et al, 2016). Based on a LOFAR station firmware, it provides a set of 200 kHz digital single polarization waveforms from 2 independent beams.…”

Section: Overviewmentioning

confidence: 99%

Multi-Level Pre-Correlation RFI Flagging for Real-Time Implementation on UniBoard

Dumez-Viou

Weber

Ravier

2016

J. Astron. Instrum.

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International audienceBecause of the denser active use of the spectrum, and because of radio telescopes higher sensitivity, radio frequency interference (RFI) mitigation has become a sensitive topic for current and future radio telescope designs. Even if quite sophisticated approaches have been proposed in the recent years, the majority of RFI mitigation operational procedures are based on post-correlation corrupted data flagging. Moreover, given the huge amount of data delivered by current and next generation radio telescopes, all these RFI detection procedures have to be at least automatic and, if possible, real-time. In this paper, the implementation of a real-time pre-correlation RFI detection and flagging procedure into generic high-performance computing platforms based on field programmable gate arrays (FPGA) is described, simulated and tested. One of these boards, UniBoard, developed under a Joint Research Activity in the RadioNet FP7 European programme is based on eight FPGAs interconnected by a high speed transceiver mesh. It provides up to 4 TMACs with (R) Altera Stratix IV FPGA and 160 Gbps data rate for the input data stream. The proposed concept is to continuously monitor the data quality at different stages in the digital preprocessing pipeline between the antennas and the correlator, at the station level and the core level. In this way, the detectors are applied at stages where different time-frequency resolutions can be achieved and where the interference-to-noise ratio (INR) is maximum right before any dilution of RFI characteristics by subsequent channelizations or signal recombinations. The detection decisions could be linked to a RFI statistics database or could be attached to the data for later stage flagging. Considering the high in-out data rate in the pre-correlation stages, only real-time and go-through detectors (i.e. no iterative processing) can be implemented. In this paper, a realtime and adaptive detection scheme is described. An ongoing case study has been set up with the Electronic Multi-Beam Radio Astronomy Concept (EMBRACE) radio telescope facility at Nancay Observatory. The objective is to evaluate the performances of this concept in term of hardware complexity, detection efficiency and additional RFI metadata rate cost. The UniBoard implementation scheme is described

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Characterization of a dense aperture array for radio astronomy

Cited by 13 publications

References 22 publications

Design, operation and performance of the PAON4 prototype transit interferometer

Design, operation and performance of the PAON4 prototype transit interferometer

All-sky radio SETI

Multi-Level Pre-Correlation RFI Flagging for Real-Time Implementation on UniBoard

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