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Extending terrestrial networks into low-altitude airspace is a practical way to support aerial services, and accurate low-altitude radio maps are essential for characterizing terrestrial base station (BS) coverage and guiding system design.…

Signal Processing · Electrical Eng. & Systems 2026-05-25 Bowen Li , Haotian Zhang , Mu Jia , Junting Chen , Nikolaos Pappas

This manual is intended to help ALMA and other interferometer users improve images by recognising limitations and how to overcome them and deciding when and how to use self-calibration. The images provided by the ALMA Science Archive are…

Instrumentation and Methods for Astrophysics · Physics 2022-07-13 A. M. S. Richards , E. Moravec , S. Etoka , E. B. Fomalont , A. F. Pérez-Sánchez , M. C. Toribio , R. A. Laing

The ambitious scientific goals of the SKA require a matching capability for calibration of atmospheric propagation errors, which contaminate the observed signals. We demonstrate a scheme for correcting the direction-dependent ionospheric…

Instrumentation and Methods for Astrophysics · Physics 2018-07-18 Maria Rioja , Richard Dodson , Thomas Franzen

Precise frequency and phase synchronization are among the important aspects in a coherent distributed phased array antenna system, and are among the most challenging to achieve for microwave frequencies and above. We propose a high accuracy…

Systems and Control · Electrical Eng. & Systems 2023-06-09 Mohammed Rashid , Jeffrey A. Nanzer

Radio-frequency interference (RFI) is becoming an increasingly significant problem for most radio telescopes. Working with Green Bank Telescope data from PSR J1730+0747 in the form of complex-valued channelized voltages and their respective…

Instrumentation and Methods for Astrophysics · Physics 2024-08-14 Zhicheng Cao , Natalia A. Schmid , Kevin Bandura , Duncan R. Lorimer , Morgan Dameron , Katelyn Crockett , Clayton Grubick , Andreas Schmid , Shaonan Zheng

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

Contemporary real-time RFI mitigation is carried out at different stages primarily using regulatory and technical approaches. Regulatory approaches include spectrum management, radio quiet zones, and ensuring protection from self-generated…

Instrumentation and Methods for Astrophysics · Physics 2025-01-08 Kaushal D. Buch , Ruta Kale , Kishor D. Naik , Ajithkumar B. , Thushara Gunaratne , N. Habana , Gregory Hellbourg , Jane Kaczmarek , L. Petrov , Cedric Viou , Benjamin Winkel

Phased array feeds (PAFs) for reflector antennas offer the potential for increased reflector field of view and faster survey speeds. To address some of the development challenges that remain for scientifically useful PAFs, including…

Instrumentation and Methods for Astrophysics · Physics 2015-05-14 Jonathan Landon , Michael Elmer , Jacob Waldron , David Jones , Alan Stemmons , Brian D. Jeffs , Karl F. Warnick , J. Richard Fisher , Roger D. Norrod

We introduce a new pipeline for analyzing and mitigating radio frequency interference (RFI), which we call Sky-Subtracted Incoherent Noise Spectra (SSINS). SSINS is designed to identify and remove faint RFI below the single baseline thermal…

Instrumentation and Methods for Astrophysics · Physics 2019-10-10 Michael J. Wilensky , Miguel F. Morales , Bryna J. Hazelton , Nichole Barry , Ruby Byrne , Sumit Roy

Calibration of instrumental polarization is critical for measuring polarized radio emissions from astrophysical sources to extract the magnetic field information in astrophysical, heliospheric, and terrestrial plasmas. At meter wavelengths,…

Instrumentation and Methods for Astrophysics · Physics 2025-05-08 Devojyoti Kansabanik , Angelos Vourlidas , Soham Dey , Surajit Mondal , Divya Oberoi

The radio astronomy community is currently building a number of phased array telescopes. The calibration of these telescopes is hampered by the fact that covariances of signals from closely spaced antennas are sensitive to noise coupling…

Instrumentation and Methods for Astrophysics · Physics 2010-03-15 Stefan J. Wijnholds , Alle-Jan van der Veen

Calibration is a key step in the signal processing pipeline of any radio astronomical instrument. The required sky, ionospheric and instrumental models for this step can suffer from various kinds of incompleteness. In this paper we analyze…

Instrumentation and Methods for Astrophysics · Physics 2019-02-08 A. Mouri Sardarabadi , L. V. E. Koopmans

Radio Frequency Interference (RFI) is unwanted noise that swamps the desired astronomical signal. Radio astronomers have always had to deal with RFI detection and excision around telescope sites, but little has been done to understand the…

Instrumentation and Methods for Astrophysics · Physics 2022-11-17 Isaac Sihlangu , Nadeem Oozeer , Bruce Bassett

Radio interferometers observe the Fourier space of the sky, at locations determined by the array geometry. Before a real space image is constructed by a Fourier transform, the data is weighted to improve the quality of reconstruction. Two…

Instrumentation and Methods for Astrophysics · Physics 2015-06-22 Sarod Yatawatta

Calibrating out per-antenna signal chain effects is an essential step in analyzing radio interferometric data. For drift-scanning arrays, robustly calibrating the data is especially challenging due to the lack of the ability to track a…

Instrumentation and Methods for Astrophysics · Physics 2026-02-09 Robert Pascua , Jonathan Sievers , Adrian Liu

In recent works, sparse models and convex optimization techniques have been applied to radio-interferometric (RI) imaging showing the potential to outperform state-of-the-art imaging algorithms in the field. In this talk, I will review our…

Instrumentation and Methods for Astrophysics · Physics 2015-02-19 Rafael E. Carrillo , Jason D. McEwen , Yves Wiaux

Impulsive radio-frequency signals from astronomical sources are dispersed by the frequency dependent index of refraction of the interstellar media and so appear as chirped signals when they reach earth. Searches for dispersed impulses have…

Instrumentation and Methods for Astrophysics · Physics 2015-06-03 John Hogden , Scott Vander Wiel , Geoffrey C. Bower , Sarah Michalak , Andrew Siemion , Daniel Werthimer

Studying the universe through radio telescope observation is crucial. However, radio telescopes capture not only signals from the universe but also various interfering signals, known as Radio Frequency Interference (RFI). The presence of…

Instrumentation and Methods for Astrophysics · Physics 2024-04-02 Fei Gu , Longfei Hao , Bo Liang , Song Feng , Shoulin Wei , Wei Dai , Yonghua Xu , Zhixuan Li , Yihang Dao

Next-generation radio interferometers, such as the Square Kilometre Array (SKA), will revolutionise our understanding of the universe through their unprecedented sensitivity and resolution. However, standard methods in radio interferometry…

Instrumentation and Methods for Astrophysics · Physics 2017-02-23 Luke Pratley , Jason D. McEwen , Mayeul d'Avezac , Rafael E. Carrillo , Alexandru Onose , Yves Wiaux

Radio interferometers consisting of identical antennas arranged on a regular lattice permit fast Fourier transform beamforming, which reduces the correlation cost from $\mathcal{O}(n^2)$ in the number of antennas to $\mathcal{O}(n\log n)$.…

Instrumentation and Methods for Astrophysics · Physics 2019-05-20 Kiyoshi W. Masui , J. Richard Shaw , Cherry Ng , Kendrick M. Smith , Keith Vanderlinde , Adiv Paradise
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