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In radio astronomy, accurate calibration is of crucial importance for the new generation of radio interferometers. More specifically, because of the potential presence of outliers which affect the measured data, robustness needs to be…

Instrumentation and Methods for Astrophysics · Physics 2018-08-01 Virginie Ollier , Mohammed Nabil El Korso , André Ferrari , Rémy Boyer , Pascal Larzabal

A new technique is presented for producing images from interferometric data. The method, ``smear fitting'', makes the constraints necessary for interferometric imaging double as a model, with uncertainties, of the sky brightness…

Astrophysics · Physics 2009-11-11 Robert I. Reid

Techniques like speckle holography and shearography are rarely applied due to the complexity of instrument setup and lack of automated result analysis, despite their potential. By simulating speckle interferometric outcomes, we seek to…

Optics · Physics 2025-11-25 Jessica Plassmann , Michael Schuth , Georg von Freymann

We investigate synthesis of a large effective aperture using a sparse array of subarrays. We employ a multi-objective optimization framework for placement of subarrays within a prescribed area dictated by form factor constraints, trading…

Signal Processing · Electrical Eng. & Systems 2019-12-17 Anant Gupta , Upamanyu Madhow , Amin Arbabian , Ali Sadri

The short-spacing problem describes the inherent inability of radio-interferometric arrays to measure the integrated flux and structure of diffuse emission associated with extended sources. New interferometric arrays, such as SKA, require…

Instrumentation and Methods for Astrophysics · Physics 2018-07-18 S. Faridani , F. Bigiel , L. Floeer , J. Kerp , S. Stanimirovic

Phased arrays, commonly used in IEEE 802.11ad and 5G radios, are capable of focusing radio frequency signals in a specific direction or a spatial region. Beamforming achieves such directional or spatial concentration of signals and enables…

Signal Processing · Electrical Eng. & Systems 2024-10-30 Nitin Jonathan Myers , Robert W. Heath

Large-area gratings play a crucial role in various engineering fields. However, traditional interference lithography is limited by the size of optical component apertures, making large-area fabrication a challenging task. Here, a method for…

Optics · Physics 2024-11-05 Xiang Gao , Jingwen Li , Zijian Zhong , Xinghui Li

An adaptive parametric reduced-order modeling method based on interpolating poles of reduced-order models is proposed in this paper. To guarantee correct interpolation, a pole-matching process is conducted to determine which poles of two…

Numerical Analysis · Mathematics 2019-08-05 Yao Yue , Lihong Feng , Peter Benner

In near-field beam focusing for finite-sized arrays, focal shift is a non-negligible issue. The actual focal point often appears closer to the array than the predefined focal distance, significantly degrading the focusing performance of…

Signal Processing · Electrical Eng. & Systems 2025-05-13 Jiawang Li , Yingjie Xu , Hanieh Aliakbari

Object detection in astronomical images, generically referred to as source finding, is often performed before the object characterisation stage in astrophysical processing work flows. In radio astronomy, source finding has historically been…

Instrumentation and Methods for Astrophysics · Physics 2019-01-16 Luis Lucas , Tim Staley , Anna Scaife

The diffraction contrast modalities accessible by X-ray grating interferometers are not imaged directly but have to be inferred from sine like signal variations occurring in a series of images acquired at varying relative positions of the…

Instrumentation and Detectors · Physics 2021-02-01 Jonas Dittmann , Andreas Balles , Simon Zabler

The motivation to build spaceborne interferometric arrays for low-frequency radio astronomy is widely recognised because frequencies below the ionospheric cutoff are inaccessible for ground-based radio telescopes. We discuss the theoretical…

Astrophysics · Physics 2007-05-23 P. Janhunen , A. Olsson , R. Karlsson , J. -M. Griessmeier

Interferometry can measure the shape or the material density of a system that could not be measured otherwise by recording the difference between the phase change of a signal and a reference phase. This difference is always between $-\pi$…

Plasma Physics · Physics 2022-10-20 Pierre-Alexandre Gourdain , Aidan Bachmann

Interferometric phase linking (IPL) has become a prominent technique for processing images of areas containing distributed scaterrers in SAR interferometry. Traditionally, IPL consists in estimating consistent phase differences between all…

Applications · Statistics 2024-03-14 Phan Viet Hoa Vu , Arnaud Breloy , Frédéric Brigui , Yajing Yan , Guillaume Ginolhac

The present work describes a website designed for remote teaching of optical measurements using lasers. It enables senior undergraduate and postgraduate students to learn theoretical aspects of the subject and also have a means to perform…

Physics Education · Physics 2018-03-02 Veena Singh , Richa Dubey , P. K. Panigrahi , K. Muralidhar

Interferometry is a powerful technique for making sensitive, high-fidelity images of the sky, but is limited in its ability to measure extended or diffuse emission. Better images of extended astronomical objects can be obtained by…

Instrumentation and Methods for Astrophysics · Physics 2020-06-12 Brian S. Mason

The problem of multi-area interchange scheduling under system uncertainty is considered. A new scheduling technique is proposed for a multi-proxy bus system based on stochastic optimization that captures uncertainty in renewable generation…

Optimization and Control · Mathematics 2016-11-16 Yuting Ji , Lang Tong

The paper addresses the design of adaptive radar detectors having desired behavior, in Gaussian disturbance with unknown statistics. Specifically, given detection probability specifications for chosen signal-to-noise ratios and steering…

Signal Processing · Electrical Eng. & Systems 2022-11-23 Angelo Coluccia , Alessio Fascista , Giuseppe Ricci

Instruments for radio astronomical observations have come a long way. While the first telescopes were based on very large dishes and 2-antenna interferometers, current instruments consist of dozens of steerable dishes, whereas future…

Instrumentation and Methods for Astrophysics · Physics 2015-03-13 Stefan J. Wijnholds , Sebastiaan van der Tol , Ronald Nijboer , Alle-Jan van der Veen

A crucial challenge to the scaling up of linear optical interferometers is the presence of defective optical components resulting from inevitable imperfections in fabrication and packaging. This work presents a method for circumventing such…

Quantum Physics · Physics 2019-12-19 Ish Dhand