Results 71 to 80 of about 3,469 (207)

An Ionospheric Disturbed Index Based on ROTI

open access: yesSpace Weather, Volume 23, Issue 6, June 2025.
Abstract The ionosphere has significant impacts on wireless communication, satellite navigation, and space weather. Based on hundreds of global GNSS observation stations, we calculate the rate of TEC index (ROTI). Through the analysis of ROTI, we establish a global ionospheric disturbed index (IDI) to directly characterize ionospheric disturbances ...
Cheng Wang, Xiaoxue Min, Hong Hu
wiley   +1 more source

Transit satellite system timing capabilities [PDF]

open access: yes, 1978
Current time transfer capabilities of the Transit Satellite System are reviewed. Potential improvements in the changes in equipment and operational procedures using operational satellites are ...
Finsod, T. D.
core   +1 more source

Assessing 1‐Second ROTI for Ionospheric Perturbation Monitoring Using Real‐Time Multi‐GNSS Data in China

open access: yesSpace Weather, Volume 23, Issue 2, February 2025.
Abstract With the onset of solar activities of the 25th solar cycle, ionospheric perturbations have become increasingly frequent, posing significant challenges to various applications of Global Navigation Satellite Systems (GNSS). The Rate of Total Electron Content (TEC) Index (Rate of TEC Index (ROTI)), commonly derived from GNSS data sampled at 30‐s ...
Zhouyu Zhang   +6 more
wiley   +1 more source

Enhancing System Capacity Through Joint Space‐Ground Multi‐Beam Coordination for LEO Satellite Systems

open access: yesEngineering Reports, Volume 7, Issue 1, January 2025.
ABSTRACT Due to the long transmission distance of the constellation network represented by the low‐orbit satellite system, the satellite‐to‐ground link is subject to large path loss and limited communication performance. This paper uses multi‐satellite and multi‐beam joint transmission technology to form a virtual multiplex network with ground multi ...
Yuyang Liu, Tong Shi, Hua Wang
wiley   +1 more source

Physical layer security in satellite communication: State‐of‐the‐art and open problems

open access: yesIET Communications, Volume 19, Issue 1, January/December 2025.
This paper first classifies contemporary satellite communication networks into five domains and then analyse the use of PLS in each domain; these domains are hybrid satellite‐terrestrial networks, satellite‐based IoT, navigation satellite systems, FSO‐based satellites, and inter‐satellite communications.
Nora Abdelsalam   +2 more
wiley   +1 more source

Investigation on the Impact of Tropospheric Delay on GPS Height Variation near the Equator

open access: yes, 2009
One of the major problems currently facing satellite-based positioning is the atmospheric refraction of the GPS signal caused by the troposphere. The tropospheric effect is much more pronounced at the equatorial region due to its hot and wet conditions ...
Dodo, Joseph D   +2 more
core   +1 more source

Design and Reception Method of Code Shift Keying Signals With Power‐of‐Two Phase Intervals

open access: yesIET Radar, Sonar &Navigation, Volume 19, Issue 1, January/December 2025.
A novel approach for the design and reception of CSK signals with a phase interval mapping of power‐of‐two chips is proposed. This method is capable of significantly reducing the demodulation complexity while mitigating the intersymbol interference. ABSTRACT Precise point positioning (PPP) technology has garnered extensive attention for its ability to ...
Nengjie Yu   +4 more
wiley   +1 more source

Representations of Time Coordinates in FITS

open access: yes, 2014
In a series of three previous papers, formulation and specifics of the representation of World Coordinate Transformations in FITS data have been presented. This fourth paper deals with encoding time.
Allen, Steven L.   +5 more
core   +1 more source

Feedback Node Aided Distributed Spoofing System for Global Navigation Satellite System Time Synchronisation Attack

open access: yesIET Radar, Sonar &Navigation, Volume 19, Issue 1, January/December 2025.
This article proposes a feedback node aided distributed spoofing (FNA‐DS) system, enabling flexible implementation of distributed spoofing. Field experiments using a self‐developed distributed spoofing prototype validate the FNA‐DS system's effectiveness and expose limitations in existing direction of arrival based anti‐spoofing techniques.
Minghan Zhong   +3 more
wiley   +1 more source

Mass-Market Receiver for Static Positioning: Tests and Statistical Analyses [PDF]

open access: yes, 2011
Nowadays, there are several low cost GPS receivers able to provide both pseudorange and carrier phase measurements in the L1band, that allow to have good realtime performances in outdoor condition.
Cina, Alberto, Marucco, G., Piras, Marco
core  

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