Results 71 to 80 of about 78,703 (214)
Analysis of GNSS Interference Events Based on TRITON GNSS-R Measurements
NavigationAlthough the issue of global navigation satellite system (GNSS) interference has been addressed in the community of satellite navigation, the extent of GNSS interference in the past couple of years has raised serious concerns for air and marine ...
Jyh-Ching Juang, Yung-Fu Tsai
doaj +1 more source
A Modified Hierarchical Vision Transformer for Soil Moisture Retrieval From CYGNSS Data
Water Resources Research, Volume 62, Issue 1, January 2026.Abstract This research introduces a new deep learning (DL) framework, multi‐head self‐attention‐aided vision Transformer (MSA‐ViT), for soil moisture (SM) retrieval using Cyclone Global Navigation Satellite System (CYGNSS) data. We first assess the sensitivity of CYGNSS reflectivity (Γ) $({\Gamma })$ to SM, demonstrating a strong physical linkage ...
Qingyun Yan +4 more
wiley +1 more source
GNSS signal acquisition in the presence of sign transitions [PDF]
, 2009 The next generation of Global Navigation Satellite Systems (GNSS), such as Galileo [1] and GPS modernization [2], will use signals with equal code and bit periods, which will introduce a potential sign transition in each segment of the signal processed ...
Kewen Sun +3 more
core
Considerations for Coherent Integration in Spaceborne GNSS-Reflectometry
IEEE Geoscience and Remote Sensing LettersThe fundamental observable in Global Navigation Satellite System Reflectometry (GNSS-R) is the so-called DelayDoppler Map (DDM), which is derived from the cross-correlation of the reflected signal with either the direct signal or a locally generated replica of the transmitted signal as implemented in our algorithm.
Yasir M. O. Abbas +4 more
openaire +2 more sources
Recent progress on forward scattering modeling for GNSS reflectometry [PDF]
2014 IEEE Geoscience and Remote Sensing Symposium, 2014 A geometric optics limit of the Kirchhoff approximation is widely used for modeling the bistatic radar cross section of the ocean surface. The question of practically acceptable accuracy of this approximation for GNSS-R applications remains open. In this paper we use more accurate approximation, the small slope approximation to assess the validity of ...
Valery U. Zavorotny +1 more
openaire +3 more sources
Advances in Astronomy, Volume 2026, Issue 1, 2026.Low Earth orbit (LEO) constellations are increasingly deployed to provide integrated services such as communication, navigation augmentation, and remote sensing. However, traditional constellation designs—such as Walker, streets‐of‐coverage (SoC), and Flower constellations—rely on distinct parameter sets, making unified optimization of hybrid ...
Lin Pan +7 more
wiley +1 more source
What's Next for Snow: Insights From the NASA Terrestrial Hydrology Program Community Snow Meeting
Earth's Future, Volume 13, Issue 12, December 2025.Abstract Earth's snow cover strongly influences the climate system and represents an important resource for agricultural, industrial, and domestic water use. The last decade of snow‐focused research has improved our understanding of snow across scales. These efforts have culminated in new snow measurement instruments and methods, operational models for
Kate Hale +9 more
wiley +1 more source
GNSS reflectometry for land remote sensing applications
, 2023 Soil moisture and vegetation biomass are two essential parameters from a scienti c and economical point of view. On one hand, they are key for the understanding of the hydrological and carbon cycle. On the other hand, soil moisture is essential for agricultural applications and water management, and vegetation biomass is crucial for regional ...
openaire +4 more sources
Geophysical Research Letters, Volume 52, Issue 20, 28 October 2025.Abstract Flooding events are a major contributor to natural disasters across the global tropics. However, reliable flood data are sparse, which limits our ability to understand flood dynamics across spatial and temporal scales. Here, data from the CYGNSS SmallSat constellation are utilized to identify small‐ to regional‐scale flooding events in Sumatra.
Zofia Baldysz +4 more
wiley +1 more source
Agrosystems, Geosciences &Environment, Volume 8, Issue 3, September 2025.Abstract High‐resolution geospatial soil moisture measurements are needed to inform hydrological modeling and to guide water management in agriculture, especially in highly heterogeneous systems such as micro‐irrigated orchards. In this research, we used a Portable L‐band Radiometer (PoLRa) to map very high‐resolution (<2 m) soil surface moisture in ...
Elia Scudiero +7 more
wiley +1 more source