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Related papers: Calibration of Low-Frequency, Wide-Field Radio Int…

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This paper presents a method for reconstructing an acoustic source located in a two-layered medium from multi-frequency phased or phaseless far-field patterns measured on the upper hemisphere. The interface between the two media is assumed…

Numerical Analysis · Mathematics 2024-12-10 Yan Chang , Yukun Guo , Yue Zhao

With ever increasing data rates produced by modern radio telescopes like LOFAR and future telescopes like the SKA, many data processing steps are overwhelmed by the amount of data that needs to be handled using limited compute resources.…

Instrumentation and Methods for Astrophysics · Physics 2020-03-18 Sarod Yatawatta

We study the impact of sky-based calibration errors from source mismodeling on 21\,cm power spectrum measurements with an interferometer and propose a method for suppressing their effects. While emission from faint sources that are not…

Cosmology and Nongalactic Astrophysics · Physics 2017-07-26 Aaron Ewall-Wice , Joshua S. Dillon , Adrian Liu , Jacqueline Hewitt

Radio frequency interference (RFI) have been an enduring concern in radio astronomy, particularly for the observations of pulsars which require high timing precision and data sensitivity. In most works of the literature, RFI mitigation has…

Instrumentation and Methods for Astrophysics · Physics 2024-02-22 Xiao Zhang , Ismaël Cognard , Nicolas Dobigeon

Sub-sampling can acquire directly a passband within a broad radio frequency (RF) range, avoiding down-conversion and low-phase-noise tunable local oscillation (LO). However, sub-sampling suffers from band folding and self-image…

Instrumentation and Detectors · Physics 2017-07-29 Wenhui Hao , Yitang Dai , Feifei Yin , Yue Zhou , Jianqiang Li , Jian Dai , Wangzhe Li , Kun Xu

We introduce a new class of iterative image reconstruction algorithms for radio interferometry, at the interface of convex optimization and deep learning, inspired by plug-and-play methods. The approach consists in learning a prior image…

Image and Video Processing · Electrical Eng. & Systems 2022-09-28 Matthieu Terris , Arwa Dabbech , Chao Tang , Yves Wiaux

The sensitivity of radio astronomical stations is often limited by man-made radio frequency interference (RFI) due to a variety of terrestrial activities. An RFI mitigation subsystem (RFIMS) based on real-time digital signalprocessing is…

Instrumentation and Methods for Astrophysics · Physics 2015-05-20 P. A. Fridman , W. A. Baan , R. P. Millenaar

The desire for wide-field of view, large fractional bandwidth, high sensitivity, high spectral and temporal resolution has driven radio interferometry to the point of big data revolution where the data is represented in at least three…

Instrumentation and Methods for Astrophysics · Physics 2020-09-30 M. Atemkeng , O. Smirnov , C. Tasse , G. Foster , S. Makhathini

The recent demonstration of a real-time direct imaging radio interferometry correlator represents a new capability in radio astronomy. However wide field imaging with this method is challenging since wide-field effects and array…

Instrumentation and Methods for Astrophysics · Physics 2020-01-08 James Kent , Adam P. Beardsley , Landman Bester , Steve F. Gull , Bojan Nikolic , Jayce Dowell , Nithyanandan Thyagarajan , Greg B. Taylor , Judd Bowman

Radio Frequency Interference (RFI) greatly reduces sensitivity of radio observations to astrophysical signals and creates false positive candidates in searches for radio transients. Real signals are missed while considerable computational…

Instrumentation and Methods for Astrophysics · Physics 2025-10-06 Joseph W. Kania , Kevin Bandura , Duncan R. Lorimer , Richard Prestage

Modern radio astronomy instruments generate vast amounts of data, and the increasingly challenging radio frequency interference (RFI) environment necessitates ever-more sophisticated RFI rejection algorithms. The "needle in a haystack"…

Signal Processing · Electrical Eng. & Systems 2024-01-22 Peter Xiangyuan Ma , Steve Croft , Chris Lintott , Andrew P. V. Siemion

This paper reported a general noninterferometric high-accuracy quantitative phase imaging (QPI) method for arbitrary complex valued objects. Given by a typical 4f optical configuration as the imaging system, three frames of small-window…

Image and Video Processing · Electrical Eng. & Systems 2021-05-05 Jianhui Huang , An Pan , Huiliang Jin , Guoxiang Meng , Qian Ye

The search for extraterrestrial intelligence (SETI) commensal surveys aim to scan the sky to detect technosignatures from extraterrestrial life. A major challenge in SETI is the effective mitigation of radio frequency interference (RFI), a…

Instrumentation and Methods for Astrophysics · Physics 2026-01-21 Li-Li Zhao , Xiao-Hang Luan , Xin Chao , Yu-Chen Wang , Jian-Kang Li , Zhen-Zhao Tao , Tong-Jie Zhang , Hong-Feng Wang , Dan Werthimer

The sensitivity of radio telescopes is becoming increasingly limited by the presence of radio frequency interference (RFI), which will worsen as the radio spectrum becomes more crowded. One context where this poses a challenge is the field…

Radio interferometry calibration and Radio Frequency Interference (RFI) removal are usually done separately. Here we show that jointly modelling the antenna gains and RFI has significant benefits when the RFI follows precise trajectories,…

Instrumentation and Methods for Astrophysics · Physics 2025-02-19 Chris Finlay , Bruce A. Bassett , Martin Kunz , Nadeem Oozeer

Differential encoding and decoding can be employed to circumvent channel estimation in wireless relay networks. This article studies differential amplify-and-forward relaying using linear combining with arbitrary fixed combining weights in…

Information Theory · Computer Science 2016-11-18 M. R. Avendi , Ha H. Nguyen , Dac-Binh Ha

We propose a new stopping criterion for Krylov subspace iterative regularization of large-scale ill-posed inverse problems. Our stopping criterion accurately filters the data using a generalization of the Picard parameter that was…

Numerical Analysis · Mathematics 2017-07-14 Eitan Levin , Alexander Y. Meltzer

We describe a "spatio-spectral" deconvolution algorithm for wide-band imaging in radio interferometry. In contrast with the existing multi-frequency reconstruction algorithms, the proposed method does not rely on a model of the…

Instrumentation and Methods for Astrophysics · Physics 2016-03-01 André Ferrari , Jérémy Deguignet , Chiara Ferrari , David Mary , Antony Schutz , Oleg Smirnov

We present a new method, called "forced-spectrum fitting", for physically-based spectral modelling of radio sources during deconvolution. This improves upon current common deconvolution fitting methods, which often produce inaccurate…

Ultrasound imaging often suffers from image degradation stemming from phase aberration, which represents a significant contributing factor to the overall image degradation in ultrasound imaging. Frequency-space prediction filtering or FXPF…

Image and Video Processing · Electrical Eng. & Systems 2023-08-24 Mostafa Sharifzadeh , Habib Benali , Hassan Rivaz