Results 31 to 40 of about 169 (129)
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 +2 more
wiley +1 more source
Izračun položaja GPS-satelita iz podatkov preciznih efimerid : GPS-orbit computation from precise ephemeris data [PDF]
The article describes the theoretical point of view of the GPS precise ephemerides application that should be used in most precise GPS processing. Regarding broadcast, precise ephemerides allow us to achieve a much better accuracy of the final GPS ...
Bojan Stopar +1 more
doaj
SMTC Configuration and Window Adjustment Strategies for Beam Hopping in NR‐NTN
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
Empirical Assessment of Storm‐Time Thermospheric Density Inversion Methods From LEO POD Data
Abstract Thermospheric mass density is one of the largest sources of operational uncertainty for spacecraft in low Earth orbit, particularly during geomagnetic storms. The growing population of Global Navigation Satellite System‐equipped satellites presents a data set of opportunity: precise orbit determination (POD) data streams can be used to ...
Charles Constant +4 more
wiley +1 more source
High‐Latitude GPS Position Error During Substorms
Abstract Substorms produce rapid fluctuations in Global Navigation Satellite System (GNSS) signals, leading to degraded positioning performance at high latitudes. This study investigates the correlation of auroral structures on Global Positioning System (GPS) Precise Point Positioning (PPP) error during three substorm events with different strengths ...
Weixuan Liao +6 more
wiley +1 more source
Abstract Information on river velocities enhances understanding flood hazards, evaluating habitat conditions, and predicting the transport of floating materials. In this follow‐up study, we used data from two new sites, one with a more complex morphology and the other with a lower suspended sediment concentration, to provide further evidence that ...
Carl J. Legleiter +3 more
wiley +1 more source
LEO (Low Earth Orbit)-based PNT (Positioning, Navigation and Timing) has become a research topic of much interest and a focus of development. As LEO satellites for PNT are expected to independently provide space-time references in the future, similar to ...
Zhao Xi, Yu Baoguo, Luo Bin
doaj +1 more source
A Robust Autonomous Timekeeping Scheme For Navigation Constellations Using Inter‐Satellite Links
This letter proposes a robust autonomous timekeeping scheme for navigation constellations that utilises inter‐satellite link measurements to mitigate on‐orbit clock anomalies. By cross‐evaluating clock stability between two independent ensemble groups and dynamically optimising their weights via particle swarm optimisation, the method effectively ...
Lihao Yin +3 more
wiley +1 more source
Enhancing Security and Transparency in Satellite Data Transactions Using Ethereum‐Based Blockchain
This study presents an Ethereum‐based framework for securing satellite data transactions using ERC1155 tokenization, Proof of Authority consensus, and Threshold Cryptography. The system achieves low latency, high throughput, and significantly reduced gas costs while providing strong resistance against MITM, Sybil, and reentrancy attacks.
Saha Reno +3 more
wiley +1 more source
The Impact of the 2024 Mother's Day Storm on Aircraft Surveillance Across Europe
Abstract The Mother's day storm from 10–13 May 2024 is one of the most extreme space weather events recorded in recent decades and triggered a strong ionospheric response with various impacts on communication and navigation systems. In this study the impact on the aviation sector, and more specifically air traffic management, is investigated with ...
Erik Schmölter, Jens Berdermann
wiley +1 more source

