Results 51 to 60 of about 6,726 (227)

Low‐Complexity Hybrid Beamforming for LEO Satellites: Beam Update Rate Analysis and Advanced Adaptive Precoding

International Journal of Satellite Communications and Networking, EarlyView.
ABSTRACT Low Earth Orbit (LEO) satellite constellations offer unprecedented opportunities for global broadband connectivity but pose significant beamforming challenges due to rapid platform motion and stringent onboard hardware constraints. Fully digital architectures, while optimal in theory, remain impractical for satellite payloads, motivating ...
Mohammad Momani, Thomas Delamotte, Andreas Knopp   +2 more
wiley   +1 more source

Joint analysis of JUICE and Europa Clipper tracking data to study the Jovian system ephemerides and dissipative parameters

Astronomy & Astrophysics
Jupiter and its moons form a complex dynamical system that includes several coupling dynamics at different frequencies. In particular, the Laplace resonance is fundamental to maintaining the energy dissipation that sustain Io’s volcanic activity and ...
A. Magnanini, M. Zannoni, Luis Gomez Casajus, P. Tortora, V. Lainey, Erwan Mazarico, R. Park, L. Iess   +7 more
semanticscholar   +1 more source

SMTC Configuration and Window Adjustment Strategies for Beam Hopping in NR‐NTN

International Journal of Satellite Communications and Networking, EarlyView.
ABSTRACT Beam hopping is an effective transmission strategy for nonterrestrial networks (NTNs), enabling satellites to allocate limited power and spectrum resources across different geographical regions over time. However, in NR‐based NTN systems, beam hopping complicates synchronization monitoring because synchronization signal block (SSB) arrivals ...
Hee Wook Kim, Kyungrak Lee, Joon Gyu Ryu
wiley   +1 more source

GNSS Real-Time ZTD/PWV Retrieval Based on PPP with Broadcast Ephemerides

Atmosphere
GNSS precise point positioning (PPP) plays an important role in retrieving atmospheric water vapor values and performing numerical weather prediction. However, traditional PPP relies on real-time orbits and clocks, which require continuous internet or ...
Zongqiu Xu, Shuhao Liu, Yantian Xu, Longjiang Tang, Nannan Yang, Gen Zhang   +5 more
semanticscholar   +1 more source

Orbital Period Refinement of CoRoT Planets with TESS Observations

Frontiers in Astronomy and Space Sciences, 2021
CoRoT was the first space mission dedicated to exoplanet detection. Operational between 2007 and 2012, this mission discovered 37 transiting planets, including CoRoT-7b, the first terrestrial exoplanet with a measured size. The precision of the published
Peter Klagyivik , Peter Klagyivik , Peter Klagyivik , Hans J. Deeg , Hans J. Deeg , Szilárd Csizmadia , Juan Cabrera , Grzegorz Nowak , Grzegorz Nowak    +8 more
doaj   +1 more source

Altered photoperiod affects behaviour in a key fish grazer, the thinlip grey mullet, Chelon ramada

Journal of Fish Biology, EarlyView.
Abstract The aim of this study is to address experimentally the immediate impacts of an alteration of the photoperiod, simulating an extreme artificial light pollution, on the behaviour and stress of a key grazer fish common in temperate coastal ecosystems in Europe, the thinlip grey mullet, Chelon ramada.
Caroline Roux, Alex Bois, Patrick Chèvre, Fabrice Vétillard, Philippe Jatteau, Marie‐Laure Bégout, Soizic Morin, Laure Carassou   +7 more
wiley   +1 more source

The Influence of Different Solar System Planetary Ephemerides on Pulsar Timing

Research in Astronomy and Astrophysics
Pulsar timing offers a comprehensive avenue for exploring diverse topics in physics and astrophysics. High-precision solar system planetary ephemeris is crucial for pulsar timing as it provides the positions and velocities of solar system planets ...
J. Dai, W. Han, Na Wang
semanticscholar   +1 more source

Securing the Legacy of TESS through the Care and Maintenance of TESS Planet Ephemerides [PDF]

Astronomical Journal, 2019
Much of the science from the exoplanets detected by the Transiting Exoplanet Survey Satellite (TESS) mission relies on precisely predicted transit times that are needed for many follow-up characterization studies.
D. Dragomir, M. Harris, J. Pepper, T. Barclay, S. Villanueva, G. Ricker, R. Vanderspek, D. Latham, S. Seager, J. Winn, J. Jenkins, D. Ciardi, G. Fűrész, Christopher E. Henze, I. Mireles, E. Morgan, E. Quintana, E. Ting, D. Yahalomi   +18 more
semanticscholar   +1 more source

City of God and the Duty of Just Memory

Modern Theology, EarlyView.
Abstract In a recent essay, Richard Miller claims that Augustine presumes a duty to remember justly in his City of God. However, Miller's brief reference to a presumed duty of “just memory” does not fully explain how Augustine conceptualizes this duty or how it relates to his theological concerns.
Zachary J. Taylor
wiley   +1 more source

A Natural History of ‘Annoyances’: Knowing Weeds and Weeding Knowledge in the Early Royal Society and its ‘Georgicall Committee’

Renaissance Studies, EarlyView.
ABSTRACT Seventeenth‐century virtuosi often figured themselves as epistemic weeders, grubbing up rank thickets of accumulated error. In this article, I argue that these metaphors were unnerved by the shifting status of weeds—ostensibly unwanted plants from the margins of cultivated space, unploughed land or the disturbed soils between growing crops—in ...
Francis Taylor
wiley   +1 more source