Science topic

Global Navigation Satellite System - Science topic

A satellite navigation or SAT NAV system is a system of satellites that provide autonomous geo-spatial positioning with global coverage. A satellite navigation system with global coverage may be termed a global navigation satellite system or GNSS. Global coverage for each system is generally achieved by a satellite constellation of 20–30 medium Earth orbit (MEO) satellites spread between several orbital planes. The actual systems vary, but use orbit inclinations of >50° and orbital periods of roughly twelve hours (at an altitude of about 20,000 kilometres (12,000 mi)).
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Publications related to Global Navigation Satellite System (10,000)
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Article
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Precipitable water vapour (PWV) plays an important role in rain prediction; up to now, lots of different measuring methods and devices are developed to observe PWV. In this paper, radiosonde techniques are used to compute PWV’s spatial and temporal variations and GNSS (Global Navigation Satellite Systems) using in spatial only. GNSS data (GPS and G...
Article
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GNSS İnterferometrik Reflektometri (GNSS-IR) yöntemi, GNSS verilerinin analizi ile anten etrafındaki çevresel özelliklerin kestirimine olanak sağlamaktadır. Deniz kıyısındaki GNSS antenlerinin, deniz yüzeyinden yansıma alabilecek kadar yeterli açık görüş açısına sahip olması durumunda, GNSS-IR yöntemine dayalı olarak deniz seviyesi değişimleri beli...
Article
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Precipitable water vapor (PWV) is a meteorological variable that impacts the major atmospheric processes. It is a non-homogeneous variable that differs spatially and temporally. The spatial and temporal variability of the PWV in Egypt is investigated in this study using Global Navigation Satellite Systems (GNSS) Radio Occultation (RO) from 2006 to...
Article
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Within the framework of differential augmentation, this paper introduces the basic technical framework and performance of the BeiDou Global Navigation Satellite System (BDS-3) Satellite-Based Augmentation System (BDSBAS), including orbit products, satellite clock offset products, ionosphere and its integrity performance. The basic principle of BDS-...
Article
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Background Accurate mapping of forest canopy heights at a fine spatial resolution over large geographical areas is challenging. It is essential for the estimation of forest aboveground biomass and the evaluation of forest ecosystems. Yet current regional to national scale forest height maps were mainly produced at coarse-scale. Such maps lack spati...
Article
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Real-Time Kinematic Precise Point Positioning (PPP–RTK) is inextricably linked to external ionospheric information. The PPP–RTK performances vary much with the accuracy of ionospheric information, which is derived from different network scales, given different prior variances, and obtained under different disturbed ionospheric conditions. This stud...
Article
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Abstract Postseismic deformations continue to occur for a long period after major earthquakes. Temporal changes in postseismic deformations can be approximated using simple functions. Since the 2011 Tohoku-Oki earthquake, operating global navigation satellite system stations have been continuously accumulating a remarkable amount of relevant data....
Article
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Monitoring of crustal deformation provides essential information for seismology and volcanology. For such earth science fields and other purposes, various Global Navigation Satellite System (GNSS) networks have been constructed at the national and regional levels. In Japan, the continuous nationwide GNSS network, the GNSS Earth Observation Network...
Thesis
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Water vapor in the troposphere represents a mere fraction of the total atmospheric volume, but is strongly associated with climate change, atmospheric radiation, weather pattern, and hydrologic cycle. Accurate information on water vapor distribution not only leads to a better understanding of the various atmospheric processes, but also to enhanced...
Article
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As effective backups for global navigation satellite systems (GNSS), ground-based navigation systems can provide positioning, navigation, and timing services in situations in which the GNSS signal is degraded or denied, such as city canyons, underground, and tunnels. To handle the issue of the poor performance of small cycle slip detection in singl...
Article
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In urban areas, global navigation satellite system (GNSS) measurements are susceptible to multipath and non-line-of-sight (NLOS) effects, significantly degrading GNSS performance. Nowadays, multipath/NLOS effects have become the main cause of GNSS measurement fault in an urban environment. Our work mainly focuses on improving GNSS performance in ur...
Article
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The High Accuracy Service (HAS) is an upcoming addition to the Galileo service portfolio that offers free correction data for precise point positioning in real-time. Beyond terrestrial and aeronautical applications, precise orbit determination (POD) of satellites in low Earth orbit (LEO) has been proposed as a potential use case for HAS corrections...
Article
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Global Navigation Satellite Systems allow the users to synchronize their clock on the international time reference, the Coordinated Universal Time (UTC). To that aim, they broadcast in their navigation messages a prediction of the offset between the system reference time scale GNSST and a prediction of UTC. Due to the regular update of the navigati...
Article
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We study the impact of the severe equatorial earthquakes on the ionospheric Equatorial Ionization Anomaly (EIA) to check the variations in the shape of electron concentrations along the earthquake longitudes as the possible precursors to the earthquakes by considering a case study of a strong Mw 7.3 seismic event from Honduras occurred in 2009. We...
Article
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Earth rotation parameters (ERPs) are susceptible to absorbing the spurious effects from global navigation satellite system constellation characteristics and orbit modeling deficiencies, especially the deficiencies in the solar radiation pressure (SRP) models. This study investigates the impact of SRP modeling on the ERP estimation derived from BeiD...
Article
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In an urbanized environment, a superior baseband algorithm fundamentally enhances global navigation satellite system (GNSS) receivers by resisting interferences such as reflection leading to multipath signals and abnormal dynamics caused by user’s motion or non-line-of-sight (NLOS) signals. A carrier aiding algorithm is frequently adopted to remove...
Article
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GNSS-IR enables the extraction of environmental parameters such as snow depth by analyzing signal-to-noise ratio, indicating the strength of the GNSS signal. We propose a machine learning (ML) classification approach for snow depth retrieval using the GNSS-IR technique. ML classifier algorithms were studied to classify the strong and weak ground re...
Article
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During the evolution of global navigation satellite systems (GNSS), many new GNSS signals have been proposed to meet the demand of various applications for high-precision positioning. The single-sideband complex subcarrier (SCBOC) modulated signals, which are contained in China's third-generation BeiDou Navigation Satellite System (BDS-3) B1 wideba...
Article
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Accurate and reliable carrier phase ambiguity resolution (AR) is the key to global navigation satellite system (GNSS) high-precision navigation and positioning applications. The integer least squares (ILS) estimation and the best integer equivariant (BIE) estimation are two widely used AR method, with the former considered to have the highest succe...
Article
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Accurate secular trend estimates and their uncertainties of GNSS coordinate time series is imperative for its geophysical applications. However, trend estimates would be severely biased by complex periodicities, outliers and undetected offsets. We propose a modified robust trend estimator for GNSS time series named Median Inter-Periodic Difference...
Article
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Since the release of the phase center calibrations for both the receivers and the satellites, the BeiDou Navigation Satellite System (BDS) became a new potential contributor to the realization of the terrestrial reference frame (TRF) scale of future International Terrestrial Reference Frame releases. This study focuses on the evaluation of the pote...
Article
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Direction Lock Loop (DiLL) utilizes the direction of arrival (DOA) error obtained from the spatial correlation characteristics of the array antenna beamforming and dynamically adjusts the estimated DOA value through a closed-angle tracking loop. DiLL is a representative DOA tracking method for a direct sequence code division multiple access (DS-CDM...
Article
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Low earth orbit satellites (LEOs) play an important role in communications, Earth observation and other applications. The real-time precise orbit determination (RTPOD) of LEOs plays an important role. However, the quality of carrier observations must be strictly controlled for the RTPOD of LEO satellites. Nevertheless, the ionospheric residual (IR)...
Article
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Satellite laser ranging (SLR) retroreflectors along with GNSS receivers are installed onboard numerous active low earth orbiters (LEOs) for the independent validation of GNSS-based precise orbit determination (POD) products. SLR validation results still contain many systematic errors that require special handling of various biases. For this purpose...
Article
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The accuracy of navigation information is essential for modern transport systems. Such information includes position, velocity and attitude. Because of the physical characteristics of the operational environments, integration of GNSS with inertial measurement units (IMU) is commonly used. However, conventional integrated algorithms suffer from low-...
Article
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The BeiDou Navigation Satellite System (BDS) of China started to provide global services in 2020, which provides a new data source for snow depth sensing through the Global Navigation Satellite System Interferometric Reflectometry (GNSS-IR) technique. This study, taking advantage of two stations in the snow season of 2020, first evaluates the perfo...
Article
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The application of the global navigation satellite system (GNSS) in aviation effectively meets the requirements of aircraft location-based services. However, the GNSS application in airborne surveys mostly follows the land survey method, which ignores the particularity of the airborne flight operations, such as the rapid change of altitude differen...
Article
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A method for retrieving snow and sea ice thickness is developed and simulations are conducted to evaluate the feasibility of the proposed method. When using a defined envelope amplitude and phase, for the snow-free case, RMSEs of 0.24 and 0.34 m can be obtained; for the snow-covered case, the RMSEs of the retrieved sea ice thickness decrease to 0.4...
Article
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Multi-frequency precise point positioning (PPP) has drawn attention along with the modernization of the Global Navigation Satellite Systems. There are now nearly 90 satellites providing multi-frequency signals. This contribution aims to achieve fast convergence of a few seconds for BDS/Galileo/GPS/QZSS integrated triple-frequency PPP with integer a...
Article
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We present the modeling of annual and semiannual signals in position time series of GNSS stations. The employed method is the Complementary Ensemble Empirical Mode Decomposition (CEEMD), dedicated to analyzing nonstationary and nonlinear signals. The input data were daily time series of position residuals for 25 stations of the EUREF Permanent Netw...
Article
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Emerging applications like autonomous cars and unmanned aerial vehicles demand accurate, continuous and reliable positioning. The PPP-RTK technique, which could provide a rapid centimeter-accurate positioning service using a single GNSS receiver, has been recognized as a promising tool for mass-market and automotive applications. Nevertheless, the...
Conference Paper
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Crisis modes, following natural or human made disasters are unexpected and can take place anywhere and anytime, imposing crisis management to heavily rely on telecommunication and localisation infrastructure available during the crisis to support the execution of rescue operations. Very often in these situations, there are several challenges that n...
Conference Paper
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The safety and enforcement of preventive maintenance procedures specifically for equipment in large industrial infrastructures is a matter of major importance in particular, in the Oil and Gas industry. For example, a pump or extruder malfunction may cause disruption to the production line and thus, result in significant economic damage. An increas...
Article
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In this letter, a miniaturized high gain dual‐band circularly polarized antenna is proposed for the global satellite navigation system application. Centrosymmetric radiation structure with I‐shape branches helps improve the performance of the antenna in the low frequency within a limited area. The reflective phase modulation (RPM) surface with doub...
Article
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Global Navigation Satellite System (GNSS) has drawn the attention of scientists and users all over the world for its wide-ranging Earth observations and applications. Since the end of May 2022, more than 130 satellites are available for fully global operational satellite navigation systems, such as BeiDou Navigation Satellite System (BDS), Galileo,...
Cover Page
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The ionosphere reflects and modifies radio waves used for communication and the Global Navigation Satellite System (GNSS), highlighting the need for a comprehensive understanding of its variation. It contains day-to-day spatial/temporal variabilities and small-scale plasma disturbances. Hence, the development of high-accuracy ionospheric models rem...
Article
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The single-baseline solution (SBS) model has been widely adopted by the existing global navigation satellite system (GNSS) deformation monitoring systems due to its theoretical simplicity and ease of implementation. However, the SBS model neglects the mathematical correlation between baselines, and the accuracy and reliability can be degraded for b...
Article
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In the last decades, the increasing complexity of the fusion of proprioceptive and exteroceptive sensors with Global Navigation Satellite System (GNSS) has motivated the exploration of Artificial Intelligence related strategies for the implementation of the navigation filters. In order to meet the strict requirements of accuracy and precision for I...
Article
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Atmospheric drag provides an indirect approach for evaluating atmospheric mass density, which can be derived from the Precise Orbit Determination (POD) of Low Earth Orbit (LEO) satellites. A method was developed to estimate nongravitational acceleration, which includes the drag acceleration of the thermospheric density model and empirical force acc...
Article
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The deformation and stress fields due to a three-dimensional, pressurized magma chamber are computed using the Indirect Boundary Integral Method (IBIM) with a numerical scheme based on point, single-force distribution over the closed surface of the chamber, and Green’s function representation of the contribution of each single-force to the overall...
Article
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Ambiguity resolution at Continuously Operating Reference Station (CORS) network sites is the key step in the whole processing chain of Network Real Time Kinematic (NRTK). An appropriate ambiguity-resolution speed is important, and single-epoch ambiguity resolution has not been realized yet, especially for large-scale CORS. We attempt to realize sin...
Research
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Kalman-type filters are extremely useful in diverse real-world applications, including robotics, communication systems, GNSS, inertial navigation, chemical plant control, predicting the weather, multi-sensor data fusion, tracking of aircraft, satellites, ships, rockets, cars, people, cows, etc. Moreover, Kalman filters are relatively easy to design...
Article
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Snow plays an important role in the water cycle and global climate change, and the accurate monitoring of changes in snow depth is an important task. However, monitoring snow properties is still challenging and unclear, particularly in the Tibetan Plateau, which has rough land and uneven terrain. The traditional monitoring methods have some limitat...
Article
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Data fusion is an effective method to obtain high-precision and high-spatiotemporal-resolution precipitable water vapor (PWV) products, which play an important role in understanding climate change and meteorological monitoring. However, existing fusion methods have some shortcomings, such as ignoring the applicability of the model space or the high...
Article
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Mt. Ushba is a famous mountain in the Great Caucasus characterized by its iconical double peak. In addition, the surrounding Georgian region of Svaneti is known for its medieval defense towers, what makes the area a rising tourism destination. Climbers, hikers and visitors alike need maps for planning their tours, so there is a demand for a reliabl...
Article
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The weighted mean temperature (Tm) is crucial for converting zenith wet delay to precipitable water vapor in global navigation satellite system meteorology. Mainstream Tm models have the shortcomings of poor universality and severe local accuracy loss, and they cannot reflect the nonlinear relationship between Tm and meteorological/spatiotemporal f...
Article
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The currently available long-term snow depth data sets are either from point-scale ground measurements or from gridded satellite/modeled/reanalysis data with coarse spatial resolution, which limits the applications in climate models, hydrological models, and regional snow disaster monitoring. Benefitting from its unique advantages of cost-effective...
Article
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To support the rapid development of the Urban Air Mobility framework, safe navigation must be ensured to Vertical Take-Off and Landing aircraft, especially in the approach and landing phases. Visual sensors have the potential of providing accurate measurements with reduced budgets, although integrity issues, as well as performance degradation in lo...
Article
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With the increasingly widespread application of UAV intelligence, the need for autonomous navigation and positioning is becoming more and more important. To solve the problem that UAV cannot perform localization in complex scenes, a new multi-source fusion framework factor graph optimization algorithm is used for UAV localization state estimation i...
Article
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The accuracy of GNSS/Acoustic seafloor geodetic calibration is greatly influenced by the temporal variation of sound velocity, especially in the vertical direction. Aiming at correcting of the unknown parameters related to both the positions and the sound velocity, this paper proposes a step-by-step inversion scheme based on moving survey data. The...
Article
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Global Navigation Satellite System (GNSS) is an established atmospheric monitoring technique delivering water vapour data in near-real time with a latency of 90 min for operational Numerical Weather Prediction in Europe within the GNSS water vapour service (E-GVAP). The advancement of GNSS processing made the quality of real-time GNSS tropospheric...
Article
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With the availability of satellite carrier-phase delay corrections provided by a reference network or the International GNSS Service (IGS), the integer ambiguity resolution for a single receiver can be successfully achieved, which is the so-called PPP-RTK concept. Although PPP-RTK can significantly shorten the convergence time, it is still worthwhi...