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The redshifted $21$\,cm signal of neutral hydrogen can be used as a direct probe of the intergalactic medium during Cosmic Dawn\,(CD) and Epoch of Reionization\,(EoR). However, detecting this inherently weak signal has numerous challenges.…

Cosmology and Nongalactic Astrophysics · Physics 2025-02-28 Samit Kumar Pal , Abhirup Datta , Aishrila Mazumder

Foregrounds with polarization states that are not smooth functions of frequency present a challenge to HI Epoch of Reionization (EoR) power spectrum measurements if they are not cleanly separated from the desired Stokes I signal. The…

Instrumentation and Methods for Astrophysics · Physics 2018-12-26 Zachary E. Martinot , James E. Aguirre , Saul A. Kohn , Immanuel Q. Washington

The HI 21cm global signal from the Cosmic Dawn and the Epoch of Reionization (EoR) offers critical insights into the evolution of our Universe. Yet, its detection presents significant challenges due to its extremely low…

Cosmology and Nongalactic Astrophysics · Physics 2024-04-09 Yue Wang , Xin Wang , Shijie Sun , Fengquan Wu , Shoudong Luo , Xuelei Chen

In radio astronomy, the correlator measures intensity in visibility space. In addition, the EoR power spectrum measured by an experiment such as the MWA is constructed in visibility space. Thus, correcting for the ionosphere in the uv-plane…

Instrumentation and Methods for Astrophysics · Physics 2009-11-23 Michael S. Matejek , Miguel F. Morales

The increasing volume of space objects in Earth's orbit presents a significant challenge for Space Situational Awareness (SSA). And in particular, accurate orbit prediction is crucial to anticipate the position and velocity of space…

Machine Learning · Computer Science 2024-09-24 Francisco Caldas , Cláudia Soares

gamma ray altitude control system is an important equipment for deep space exploration and sample return mission, its main purpose is a low altitude measurement of the spacecraft based on Compton Effect at the moment when it lands on…

Instrumentation and Methods for Astrophysics · Physics 2015-05-20 Jing-Lei Liu , Chao Shen , Shi-Tong Wu , Wei Huang

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

The turbulent ionosphere causes phase shifts to incoming radio waves on a broad range of temporal and spatial scales. When an interferometer is not sufficiently calibrated for the direction-dependent ionospheric effects, the time-varying…

Cosmology and Nongalactic Astrophysics · Physics 2024-08-02 S. A. Brackenhoff , M. Mevius , L. V. E. Koopmans , A. Offringa , E. Ceccotti , J. K. Chege , B. K. Gehlot , S. Ghosh , C. Höfer , F. G. Mertens , S. Munshi , S. Zaroubi

The investigation of the Earth ionosphere both in a quiet and a disturbed states is still desirable. Despite recent progress in its modeling and in estimating the electron concentration along the line of sight by GPS signals, the impact of…

Earth and Planetary Astrophysics · Physics 2018-03-14 O. M. Ulyanov , A. I. Shevtsova , D. V. Mukha , A. A. Seredkina

The intelligent reflecting surface (IRS) technology has recently attracted a lot of interest in wireless communications research. An IRS consists of passive reflective elements capable of tuning the phase, amplitude, frequency and…

Signal Processing · Electrical Eng. & Systems 2022-06-06 Zahra Esmaeilbeig , Kumar Vijay Mishra , Mojtaba Soltanalian

Low Earth orbit (LEO) satellites offer a promising alternative to global navigation satellite systems for precise positioning; however, their relatively low altitudes make them more susceptible to orbital perturbations, which in turn…

Signal Processing · Electrical Eng. & Systems 2025-11-11 Jie Ma , Pinjun Zheng , Xing Liu , Yuchen Zhang , Ali A. Nasir , Tareq Y. Al-Naffouri

Object localization in satellite imagery is particularly challenging due to the high variability of objects, low spatial resolution, and interference from noise and dominant features such as clouds and city lights. In this research, we…

Computer Vision and Pattern Recognition · Computer Science 2025-07-09 Seraj Al Mahmud Mostafa , Chenxi Wang , Jia Yue , Yuta Hozumi , Jianwu Wang

We estimate spatial gradients in the ionosphere using the Global Positioning System (GPS) and GLONASS (Russian global navigation system) observations, utilising data from multiple GPS stations in the vicinity of Murchison Radio-astronomy…

For a ground-based radio interferometer observing at low frequencies, the ionosphere causes propagation delays and refraction of cosmic radio waves which result in phase errors in the received signal. These phase errors can be corrected…

Instrumentation and Methods for Astrophysics · Physics 2016-04-14 Poppy L. Martin , Justin D. Bray , Anna M. M. Scaife

From the prevention of natural disasters such as landslide and avalanches, to the enhancement of energy efficiencies in chemical and civil engineering industries, understanding the collective dynamics of granular materials is a fundamental…

Applied Physics · Physics 2020-10-14 Felix Rech , Kai Huang

The ionosphere introduces chromatic distortions on low frequency radio waves, and thus poses a hurdle for 21-cm cosmology. In this paper we introduce time-varying chromatic ionospheric effects on simulated antenna temperature data of a…

Instrumentation and Methods for Astrophysics · Physics 2022-07-20 Emma Shen , Dominic Anstey , Eloy de Lera Acedo , Anastasia Fialkov

The growing density of satellites in low-Earth orbit (LEO) presents serious challenges to space sustainability, primarily due to the increased risk of in-orbit collisions. Traditional ground-based tracking systems are constrained by latency…

Image and Video Processing · Electrical Eng. & Systems 2025-08-04 Peng Hu , Wenxuan Zhang

Interplanetary links (IPL) serve as crucial enablers for space exploration, facilitating secure and adaptable space missions. An integrated IPL with inter-satellite communication (IP-ISL) establishes a unified deep space network, expanding…

Signal Processing · Electrical Eng. & Systems 2024-10-29 Eray Guven , Pablo Camacho , Elham Baladi , Gunes Karabulut Kurt

This paper aims to improve the performance and positioning accuracy of a robot by using the particle filter method. The laser range information is a wireless navigation system mainly used to measure, position, and control autonomous robots.…

Robotics · Computer Science 2021-10-29 Rashid Ali , Dil Nawaz Hakro , Yongping He , Wenpeng Fu , Zhiqiang Cao

The continuously growing number of objects orbiting around the Earth is expected to be accompanied by an increasing frequency of objects re-entering the Earth's atmosphere. Many of these re-entries will be uncontrolled, making their…

Machine Learning · Computer Science 2023-03-21 Francesco Salmaso , Mirko Trisolini , Camilla Colombo