Results 21 to 30 of about 251 (164)

Precise Onboard Time Synchronization for LEO Satellites

Navigation, 2022
Onboard time synchronization is an important requirement for a wide range of low Earth orbit (LEO) missions such as altimetry or communication services, and extends to future position, navigation, and timing (PNT) services in LEO.
Florian Kunzi, Oliver Montenbruck
doaj   +1 more source

LEO Enhanced Global Navigation Satellite System (LeGNSS): progress, opportunities, and challenges

Geo-spatial Information Science, 2021
With the completion of Chinese BeiDou Navigation Satellite System (BDS), the world has begun to enjoy the Positioning, Navigation, and Timing (PNT) services of four Global Navigation Satellite Systems (GNSS).
Haibo Ge, Bofeng Li, Song Jia, Liangwei Nie, Tianhao Wu, Zhe Yang, Jingzhe Shang, Yanning Zheng, Maorong Ge   +8 more
doaj   +1 more source

Exploring the Contribution of PNT LEO Satellites to Precise Positioning Applications

Engineering Proceedings, 2023
Positioning services based on GNSS (Global Navigation Satellite Systems) have been using MEO satellites designed to guarantee Earth global coverage for decades.
Jorge Durán, Damián Socías, Enrique Carbonell, Ana González, David Calle, Irma Rodríguez   +5 more
doaj   +1 more source

Empowering the Tracking Performance of LEO PNT by Means of Meta-Signals

2020 IEEE International Conference on Wireless for Space and Extreme Environments (WiSEE), 2020
Global Navigation Satellite Systems (GNSSs) are by far the most widespread technology for Position Navigation and Timing (PNT). They have been traditionally deployed exploiting Medium Earth Orbit (MEO) or Geostationary Earth Orbit (GEO) satellite constellations. To meet future demands and overcome MEO and GEO limitations, GNSSs based on Low Earth Orbit
Nardin, Andrea, Dovis, Fabio, Fraire, Juan A.   +2 more
openaire   +2 more sources

Impact of Attitude Model, Phase Wind-Up and Phase Center Variation on Precise Orbit and Clock Offset Determination of GRACE-FO and CentiSpace-1

Remote Sensing, 2021
Currently, low Earth orbit (LEO) satellites are attracting great attention in the navigation enhancement field because of their stronger navigation signal and faster elevation variation than medium Earth orbit (MEO) satellites.
Junjun Yuan, Shanshi Zhou, Xiaogong Hu, Long Yang, Jianfeng Cao, Kai Li, Min Liao   +6 more
doaj   +1 more source

Impact of empiric potassium supplementation on mortality, sudden cardiac arrest and stroke in furosemide initiators

British Journal of Clinical Pharmacology, Volume 92, Issue 8, Page 2924-2936, August 2026.
Aim A prior non‐randomized study suggests that potassium supplementation may improve survival among furosemide initiators, and a randomized trial suggests that salt substitutes containing potassium might lower stroke risk. We conducted a retrospective cohort study using health‐care data to confirm or refute these associations among new users of ...
Thanh Phuong Pham Nguyen, Sean Hennessy, Colleen M. Brensinger, Warren B. Bilker, Laura M. Dember, Todd A. Miano, Tat‐Thang Vo, Allison W. Willis, Charles E. Leonard   +8 more
wiley   +1 more source

Demand and key technology for a LEO constellation as augmentation of satellite navigation systems

Satellite Navigation
A Low Earth Orbit (LEO) constellation augmenting satellite navigation is important in the future development of Global Navigation Satellite System (GNSS).
Yuanxi Yang, Yue Mao, Xia Ren, Xiaolin Jia, Bijiao Sun   +4 more
doaj   +1 more source

Design of CubeSat-Based Multi-Regional Positioning Navigation and Timing System in Low Earth Orbit

Aerospace
The Global Navigation Satellite System (GNSS) provides critical positioning, navigation, and timing (PNT) services worldwide, enabling a wide range of applications from everyday use to advanced scientific and military operations.
Georgios Tzanoulinos, Nori Ait-Mohammed, Vaios Lappas   +2 more
doaj   +1 more source

A Unified Vector Electromagnetic Framework for Ionospheric Scintillation and Polarization Effects in GNSS

Radio Science, Volume 61, Issue 6, June 2026.
Abstract The ionosphere imposes coupled amplitude, phase, and polarization distortions on trans‐ionospheric Global Navigation Satellite System (GNSS) signals, reflecting the structure and dynamics of electron‐density irregularities. Classical weak‐scatter theory provides a mature framework for interpreting amplitude and phase scintillation, but these ...
T. Durgonics, S. S. Beeck
wiley   +1 more source

Immunoassay and Immunohistochemistry of TDP‐43 and the association with annual rate of hippocampal atrophy in Alzheimer's disease

Alzheimer's &Dementia, Volume 20, Issue S2, December 2024.
Abstract Background Transactive response DNA‐binding protein of 43 kDa (TDP‐43) is implicated in numerous neurodegenerative diseases, including Alzheimer’s disease (AD). Immunohistochemically stained TDP‐43 is linked to faster rates of hippocampal atrophy (HA) in AD.
Hossam Youssef, Rodolfo G. Gatto, Nha Trang Thu Pham, Ronald C. Petersen, Dennis W. Dickson, Leonard Petrucelli, Jennifer L. Whitwell, Mercedes Prudencio, Keith A. Josephs   +8 more
wiley   +2 more sources