Results 51 to 60 of about 361 (154)

Impact of Ionospheric Scintillations on GNSS Availability and Precise Positioning

Space Weather, Volume 23, Issue 2, February 2025.
Abstract For many applications where accuracy, availability, and integrity are essential, such as geodetic positioning and civil aviation, Global Navigation Satellite Systems (GNSS) are indispensable. However, GNSS signal dependability is severely hampered by ionospheric disturbances, especially equatorial plasma bubbles (EPBs), particularly in ...
C. R. Aguiar, J. F. G. Monico, A. O. Moraes   +2 more
wiley   +1 more source

A Station-Specific Ionospheric Modeling Method for the Estimation and Analysis of BeiDou-3 Differential Code Bias Parameters

Navigation, 2022
A modified generalized trigonometric series (GTS) function is presented for the joint estimation of local ionospheric activities and differential code biases (DCBs) of the third-generation BeiDou navigation satellite system (BeiDou-3).
Ningbo Wang, Zishen Li, Andrzej Krankowski, Xingliang Huo   +3 more
doaj   +1 more source

A Gaussian Variogram‐Based Model of Total Electron Content in the Regional Ionosphere of China

Space Weather, Volume 22, Issue 11, November 2024.
Abstract This study utilizes ionospheric total electron contents (TECs) data from China and its surrounding areas to compute the regional ionospheric semi‐variance using the Gaussian variogram. The regional ionospheric model is then constructed by introducing an additional stochastic term, named adjusted Spherical Harmonics Adding KrigING method ...
Ang Liu, Zishen Li, Ningbo Wang, Ang Li, Zhouyu Zhang, Yunlong Zhang   +5 more
wiley   +1 more source

Revealing Inconsistencies in ROTI Index Using Multi‐GNSS Constellation Measurements: Impact of Sampling Rates and Time Window

Radio Science, Volume 59, Issue 10, October 2024.
Abstract Understanding ionospheric irregularities and their dynamics is crucial, with the rate of change of the total electron content index (ROTI) serving as a significant metric for this purpose. However, inconsistencies in ROTI magnitudes have been noted when sampled at one‐second interval across various Global Navigation Satellite System (GNSS ...
Yi Sui, Zhe Yang, Weijia Zhan
wiley   +1 more source

Modelling and Assessment of Single-Frequency PPP Time Transfer with BDS-3 B1I and B1C Observations

Remote Sensing, 2022
BDS-3 is now providing global positioning, navigation and timing (PNT) services. BDS-3 has new B1C, B2a and B2b signals compared to BDS-2. This work presents two single-frequency (SF) PPP time transfer models using BDS-3, B1C and B1I observations, and ...
Shengli Wang, Yulong Ge, Xiaolin Meng, Pengli Shen, Kaidi Wang, Fuyang Ke   +5 more
doaj   +1 more source

Modeling and Assessment of GPS/BDS Combined Precise Point Positioning

Sensors, 2016
Precise Point Positioning (PPP) technique enables stand-alone receivers to obtain cm-level positioning accuracy. Observations from multi-GNSS systems can augment users with improved positioning accuracy, reliability and availability.
Junping Chen, Jungang Wang, Yize Zhang, Sainan Yang, Qian Chen, Xiuqiang Gong   +5 more
doaj   +1 more source

Assessment of Calcium Nitrate Fertilizer as a Suitable Nitrogen Source for Cacao (Theobroma cacao L.) Cultivation in Ghana

International Journal of Agronomy, Volume 2024, Issue 1, 2024.
Urea or sulphate of ammonia fertilizer application on cacao (Theobroma cacao L.) in Ghana has either caused no changes or a decrease in cacao yields. In Ghana, soil diagnosis has shown low soil N in cacao‐growing areas, which could be limiting cacao production.
Jerome A. Dogbatse, Godfred K. Awudzi, Alfred Arthur, Frank Owusu-Ansah, Ishmael Amoako-Attah, Amos K. Quaye, Sampson Konlan, Fredrick Amon-Armah, Andrews A. Amaning, Othmane Merah   +9 more
wiley   +1 more source

Ionosphere Total Electron Content Modeling and Multi-Type Differential Code Bias Estimation Using Multi-Mode and Multi-Frequency Global Navigation Satellite System Observations

Remote Sensing, 2023
With the rapid development of multi-mode and multi-frequency GNSSs (including GPS, GLONASS, BDS, Galileo, and QZSS), more observations for research on ionosphere can be provided.
Qisheng Wang, Jiaru Zhu, Feng Hu
doaj   +1 more source

The contribution of Multi-GNSS Experiment (MGEX) to precise point positioning

Advances in Space Research, 2017
Abstract In response to the changing world of GNSS, the International GNSS Service (IGS) has initiated the Multi-GNSS Experiment (MGEX). As part of the MGEX project, initial precise orbit and clock products have been released for public use, which are the key prerequisites for multi-GNSS precise point positioning (PPP).
Guo, F., Li, X., Zhang, X., Wang, J.
openaire   +4 more sources

GPS and Galileo Precise Point Positioning Performance with Tropospheric Estimation Using Different Products: BRDM, RTS, HAS, and MGEX

Remote Sensing
The performance of Precise Point Positioning (PPP) using different Global Navigation Satellite System (GNSS) product sets, including broadcast ephemerides, International GNSS Service Real-Time Service (IGS-RTS) corrections, Galileo High Accuracy Service (
Damian Kiliszek
doaj   +1 more source