Results 61 to 70 of about 164,653 (221)

Method and apparatus for autonomous, in-receiver prediction of GNSS ephemerides [PDF]

open access: yes, 2012
Methods and apparatus for autonomous in-receiver prediction of orbit and clock states of Global Navigation Satellite Systems (GNSS) are described. Only the GNSS broadcast message is used, without need for periodic externally-communicated information ...
Bar-Sever, Yoaz E., Bertiger, William I.
core   +1 more source

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

Galileo and EGNOS as an asset for UTM safety and security [PDF]

open access: yes, 2019
GAUSS (Galileo-EGNOS as an Asset for UTM Safety and Security) is a H2020 project1 that aims at designing and developing high performance positioning systems for drones within the U-Space framework focusing on UAS (Unmanned Aircraft System) VLL (Very Low ...
Andrade-Cetto, Juan   +7 more
core  

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

Impacts of Satellite Orbit and Clock on Real-Time GPS Point and Relative Positioning

open access: yesSensors, 2017
Satellite orbit and clock corrections are always treated as known quantities in GPS positioning models. Therefore, any error in the satellite orbit and clock products will probably cause significant consequences for GPS positioning, especially for real ...
Junbo Shi   +3 more
doaj   +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

Izračun položaja GPS-satelita iz podatkov oddanih efemerid : GPS-Orbit Computation from Broadcast Ephemeris Data [PDF]

open access: yesGeodetski Vestnik, 2004
The article describes the theoretical point of view of the GPS-broadcast ephemerides application. Beside the raw GPS observations, any kind of GPS ephemerides represents indispensable data in the GPS processing engine.
Bojan Stopar   +1 more
doaj  

Accurate and Rapid Broadcast Ephemerides for Beidou-Maneuvered Satellites

open access: yesRemote Sensing, 2019
The geostationary earth orbit (GEO) and inclined geosynchronous orbit (IGSO) satellites of the Beidou navigation satellite system are maneuvered frequently. The broadcast ephemeris can be interrupted for several hours after the maneuver.
Jing Qiao   +3 more
doaj   +1 more source

Long term frequency stability analysis of the GPS NAVSTAR 6 Cesium clock [PDF]

open access: yes, 1982
Time domain measurements, taken between the NAVSTAR 6 Spacecraft Vehicle (SV) and the Vandenberg Global Positioning System (GPS) Monitor Site, by a pseudo random noise receiver, were collected over an extended period of time and analyzed to estimate the ...
Buisson, J.   +3 more
core   +1 more source

Attitude Determination from Single-Antenna Carrier-Phase Measurements

open access: yes, 2002
A model of carrier phase measurement (as carried out by a satellite navigation receiver) is formulated based on electromagnetic theory. The model shows that the phase of the open-circuit voltage induced in the receiver antenna with respect to a local ...
Bohnert J. I.   +7 more
core   +1 more source

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