Results 61 to 70 of about 467 (182)

Radar and Visual Odometry Integrated System Aided Navigation for UAVS in GNSS Denied Environment

Sensors, 2018
Drones are becoming increasingly significant for vast applications, such as firefighting, and rescue. While flying in challenging environments, reliable Global Navigation Satellite System (GNSS) measurements cannot be guaranteed all the time, and the ...
Mostafa Mostafa, Shady Zahran, Adel Moussa, Naser El-Sheimy, Abu Sesay   +4 more
doaj   +1 more source

Assessment of Commercial GNSS Radio Occultation Performance from PlanetiQ Mission

Remote Sensing
Global Navigation Satellite System (GNSS) radio occultation (RO) provides valuable 3-D atmospheric profiles with all-weather, all the time and high accuracy. However, GNSS RO mission data are still limited for global coverage.
Mohamed Zhran, Ashraf Mousa, Yu Wang, Fahdah Falah Ben Hasher, Shuanggen Jin   +4 more
doaj   +1 more source

Seeking Optimal GNSS Radio Occultation Constellations Using Evolutionary Algorithms

Remote Sensing, 2019
Given the great achievements of the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) mission in providing huge amount of GPS radio occultation (RO) data for weather forecasting, climate research, and ionosphere monitoring,
Xiaohua Xu, Yi Han, Jia Luo, Jens Wickert, Milad Asgarimehr   +4 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

GNSS Signal Jamming as Observed From Radio Occultation

IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
The jamming is found to increase significantly in recent years, and its impact is evident in Global Navigation Satellite System (GNSS) radio occultation (RO) measurements, such as those from COSMIC-2.
Dong L. Wu
doaj   +1 more source

GNSS-RO Residual Ionospheric Error (RIE): A New Method and Assessment

Atmospheric Measurement Techniques
Abstract. GNSS radio occultation (RO) observations play an increasingly important role in monitoring climate changes and numerical weather forecasts in the upper troposphere and stratosphere. The magnitudes of the RO bending angle are small at these altitudes, and therefore residual ionospheric error (RIE) is critical to retrieve vertical profiles of ...
Dong L. Wu, Valery A. Yudin, Kyu-Myong Kim, Mohar Chattopadhyay, Lawrence Coy, Ruth S. Lieberman, C. C. Jude H. Salinas, Jae N. Lee, Jie Gong, Guiping Liu   +9 more
openaire   +4 more sources

Unconstrained GNSS Water Vapor Tomography With Real Data and LEO Augmentation

Geophysical Research Letters, Volume 53, Issue 10, 28 May 2026.
Abstract The availability of four complete GNSS constellations (GPS, GLONASS, BeiDou and Galileo) offers, for the first time, the possibility of performing water vapor tomographic inversions that do not rely on external data. A tomographic model that includes no external constraints and requires no first guess and no virtual observations is described ...
P. M. A. Miranda, G. A. Hajj, J. Teixeira, P. Mateus   +3 more
wiley   +1 more source

GNSS-RO LEO satellite orbit optimization for Egypt and the Middle East region

Alexandria Engineering Journal, 2020
The “Radio Occultation (RO)” method is one from the simple, accurate and high resolution methods that produces a complete atmosphere model. Each region/country optimizes a “Low Earth Orbiter (LEO)” satellite orbit that covers its climate requirements by processing the “Global Navigation Satellite System (GNSS)” received signal.
Ibrahim Fouad Ghoniem, Ashraf El-Kutb Mousa, Gamal El-Fiky   +2 more
openaire   +2 more sources

Attributing Upper‐Tropospheric Warm Biases in CMIP6 Models to Ice Cloud‐Radiation Interaction Deficiencies Over Tropical Oceans

Geophysical Research Letters, Volume 53, Issue 9, 16 May 2026.
Abstract We assess the impact of hydrometeor radiative effects on tropical and subtropical Pacific air temperature anomalies (TAA) using Coupled Model Intercomparison Project Phase 6 (CMIP6) model simulations and satellite data. CMIP6 models are grouped by their treatment of frozen hydrometeors: SON2 (explicit cloud and falling ice), SON1 (simplified),
J.‐L. F. Li, Wei‐Liang Lee, Kuan‐Man Xu, J. H. Jiang, Yi‐Hui Wang, Yu‐Cian Tsai, S‐P. Ho, Qing Yue, Graeme Stephens, Jia‐Yuh Yu, Huiwen Chuang   +10 more
wiley   +1 more source

Artificial Intelligence in Autonomous Mobile Robot Navigation: From Classical Approaches to Intelligent Adaptation

Advanced Intelligent Systems, Volume 8, Issue 5, May 2026.
Artificial intelligence (AI) is reshaping autonomous mobile robot navigation beyond classical pipelines. This review analyzes how AI techniques are integrated into core navigation tasks, including path planning and control, localization and mapping, perception, and context‐aware decision‐making. Learning‐based, probabilistic, and soft‐computing methods
Giovanna Guaragnella, Angelo Cardellicchio, Cosimo Patruno, Massimiliano Nitti, Nicola Pedrocchi, Vito Renò   +5 more
wiley   +1 more source