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Python software to transform GPS SNR wave phases to volumetric water content / Angel Martín in GPS solutions, vol 26 n° 1 (January 2022)
[article]
Titre : Python software to transform GPS SNR wave phases to volumetric water content Type de document : Article/Communication Auteurs : Angel Martín, Auteur ; Ana Belén Anquela, Auteur ; Sara Ibáñez, Auteur ; et al., Auteur Année de publication : 2022 Article en page(s) : n° 7 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] humidité du sol
[Termes IGN] phase
[Termes IGN] Python (langage de programmation)
[Termes IGN] rapport signal sur bruit
[Termes IGN] réflectométrie par GNSS
[Termes IGN] signal GPS
[Termes IGN] teneur en vapeur d'eauRésumé : (auteur) The global navigation satellite system interferometric reflectometry is often used to extract information about the environment surrounding the antenna. One of the most important applications is soil moisture monitoring. This manuscript presents the main ideas and implementation decisions needed to write the Python code to transform the derived phase of the interferometric GPS waves, obtained from signal-to-noise ratio data continuously observed during a period of several weeks (or months), to volumetric water content. The main goal of the manuscript is to share the software with the scientific community to help users in the GPS-IR computation. Numéro de notice : A2022-004 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s10291-021-01190-3 Date de publication en ligne : 27/10/2021 En ligne : https://doi.org/10.1007/s10291-021-01190-3 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=98919
in GPS solutions > vol 26 n° 1 (January 2022) . - n° 7[article]Robust GNSS carrier phase-based position and attitude estimation theory and applications / Daniel Arias Medina (2022)
Titre : Robust GNSS carrier phase-based position and attitude estimation theory and applications Type de document : Thèse/HDR Auteurs : Daniel Arias Medina, Auteur Editeur : Madrid [Espagne] : Universidad Carlos III Année de publication : 2022 Importance : 249 p. Format : 21 x 30 cm Note générale : bibliographie
A dissertation submitted by in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Computer Science and Technology, Universidad Carlos III de MadridLangues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] classification du maximum a posteriori
[Termes IGN] constellation GNSS
[Termes IGN] estimation de pose
[Termes IGN] filtrage du bruit
[Termes IGN] méthode du maximum de vraisemblance (estimation)
[Termes IGN] phase GNSS
[Termes IGN] positionnement cinématique en temps réel
[Termes IGN] résolution d'ambiguïté
[Termes IGN] signal GNSSIndex. décimale : THESE Thèses et HDR Résumé : (auteur) Navigation information is an essential element for the functioning of robotic platforms and intelligent transportation systems. Among the existing technologies, Global Navigation Satellite Systems (GNSS) have established as the cornerstone for outdoor navigation, allowing for all-weather, all-time positioning and timing at a worldwide scale. GNSS is the generic term for referring to a constellation of satellites which transmit radio signals used primarily for ranging information. Therefore, the successful operation and deployment of prospective autonomous systems is subject to our capabilities to support GNSS in the provision of robust and precise navigational estimates. GNSS signals enable two types of ranging observations: –code pseudorange, which is a measure of the time difference between the signal’s emission and reception at the satellite and receiver, respectively, scaled by the speed of light; –carrier phase pseudorange, which measures the beat of the carrier signal and the number of accumulated full carrier cycles. While code pseudoranges provides an unambiguous measure of the distance between satellites and receiver, with a dm-level precision when disregarding atmospheric delays and clock offsets, carrier phase measurements present a much higher precision, at the cost of being ambiguous by an unknown number of integer cycles, commonly denoted as ambiguities. Thus, the maximum potential of GNSS, in terms of navigational precision, can be reach by the use of carrier phase observations which, in turn, lead to complicated estimation problems. This thesis deals with the estimation theory behind the provision of carrier phase-based precise navigation for vehicles traversing scenarios with harsh signal propagation conditions. Contributions to such a broad topic are made in three directions. First, the ultimate positioning performance is addressed, by proposing lower bounds on the signal processing realized at the receiver level and for the mixed real- and integer-valued problem related to carrier phase-based positioning. Second, multi-antenna configurations are considered for the computation of a vehicle’s orientation, introducing a new model for the joint position and attitude estimation problems and proposing new deterministic and recursive estimators based on Lie Theory. Finally, the framework of robust statistics is explored to propose new solutions to code- and carrier phase-based navigation, able to deal with outlying impulsive noises. Note de contenu : Introduction
I- A signal processing approach to satellite-based navigation
II- On the position and attitude estimation in multi-antenna GNSS
III- Robust estimation for navigation in harsh environments
Conclusions and future researchNuméro de notice : 15279 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse étrangère Note de thèse : PhD Thesis : Computer Science and Technology : Carlos III Madrid : 2022 Organisme de stage : German Aerospace Center DOI : sans En ligne : https://e-archivo.uc3m.es/handle/10016/35375#preview Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=101116
Titre : Robust GNSS phase tracking using variational bayesian inference Titre original : Méthodes de poursuite robuste de phase pour signaux GNSS basées sur l’inférence bayésienne variationnelle Type de document : Thèse/HDR Auteurs : Fabio Fabozzi, Auteur ; Stéphanie Bidon, Auteur Editeur : Toulouse : Université de Toulouse Année de publication : 2022 Importance : 173 p. Format : 21 x 30 cm Note générale : bibliographie
Thèse en vue de l'obtention du Doctorat de l'Université de Toulouse, délivré par l'Institut Supérieur de l’Aéronautique et de l’Espace, Spécialité Signal, Image, acoustique et optimisationLangues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement du signal
[Termes IGN] données GNSS
[Termes IGN] filtrage bayésien
[Termes IGN] filtre de Kalman
[Termes IGN] glissement de cycle
[Termes IGN] inférence statistique
[Termes IGN] méthode robuste
[Termes IGN] phase
[Termes IGN] rapport signal sur bruit
[Termes IGN] récepteur GNSS
[Termes IGN] signal GNSSIndex. décimale : THESE Thèses et HDR Résumé : (auteur) In this Ph.D. thesis, we are interested in robust carrier-phase estimation by using Variational Bayesian filtering. Carrier-phase measurement has become a fundamental task in many various engineering applications such as precise point positioning in GNSS (Global Navigation Satellite System). Unfortunately, phase measurements obtained by traditional phase tracking techniques may be strongly affected by the presence of ambiguous phase jumps, known as cycle slips. The latter may strongly impact the performance of the considered phase tracking algorithm leading to, in the worst case, a permanent loss of lock (drop-lock) of the signal. A re-acquistion process is then necessary which afflicts the tracking performance. Therefore, to address this problem, we propose a robust nonlinear filter for carrier-phase tracking based on Restricted Variational Bayes inference. This methodology gives us a closed-form and easy-to-implement expression of the estimator. First, the algorithm is developed only for slow phase dynamics (i.e., first-order loop), then, its order is augmented by estimating a state vector formed by the carrier-phase and its derivatives. The performance of the proposed algorithm is compared with that of conventional techniques such as DPLL (Digital Phase Lock Loop) and KF (Kalman Filter)-based DPLL in terms of precision of estimation (root-mean-square error) and cycle slipping occurrence (mean-time-to-first-slip and cycle slip rate). The comparison is firstly conducted using synthetic data, and then, real GNSS data into a GNSS software-defined-radio receiver. Results show that the proposed method outperforms the conventional linear filters, when the signal-to-noise ratio is low. Note de contenu : Introduction
1- Introduction to GNSS
2- DPLL and robust phase tracking techniques
3- RVB algorithm in case of slow dynamics
4- RVB algorithm in case of high-order dynamics
5- RVB algorithm using real GNSS data
ConclusionNuméro de notice : 15268 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse française Note de thèse : thèse de Doctorat : Signal, Image, acoustique et optimisation : Toulouse : 2022 Organisme de stage : ISAE-ONERA SCANR DOI : sans En ligne : https://depozit.isae.fr/theses/2022/2022_Fabozzi_Fabio.pdf Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=100684 Shipborne GNSS acquisition of sea surface heights in the Baltic Sea / Aive Lilibusk in Journal of geodetic science, vol 12 n° 1 (January 2022)
[article]
Titre : Shipborne GNSS acquisition of sea surface heights in the Baltic Sea Type de document : Article/Communication Auteurs : Aive Lilibusk, Auteur ; Sander Varbla, Auteur ; Artu Ellmann, Auteur ; et al., Auteur Année de publication : 2022 Article en page(s) : pp 1 - 21 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] Baltique, mer
[Termes IGN] Continuously Operating Reference Station network
[Termes IGN] hauteurs de mer
[Termes IGN] instrument embarqué
[Termes IGN] navire
[Termes IGN] positionnement cinématique
[Termes IGN] positionnement par GNSS
[Termes IGN] positionnement ponctuel précis
[Termes IGN] surface de la mer
[Vedettes matières IGN] AltimétrieRésumé : (auteur) For determining precise sea surface heights, six marine GNSS (global navigation satellite system) survey campaigns were performed in the eastern Baltic Sea in 2021. Four GNSS antennas were installed on the vessel, the coordinates of which were computed relative to GNSS–CORS (continuously operating reference stations). The GNSS–CORS results are compared to the PPP (precise point positioning)-based results. Better accuracy is associated with the GNSS–CORS postprocessed points; however, the PPP approach provided more accurate results for longer than 40 km baselines. For instance, the a priori vertical accuracy of the PPP solution is, on average, 0.050 ± 0.006 m and more stable along the entire vessel’s survey route. Conversely, the accuracy of CORS-based solutions decreases significantly when the distances from the GNSS–CORS exceed 40 km, whereas the standard deviation between the CORS and PPP-based solutions is up to 0.075 m in these sections. Note that in the harbor (about 4 km from the nearest GNSS–CORS), the standard deviation of vertical differences between the two solutions remains between 0.013 and 0.024 m. In addition, the GNSS antennas situated in different positions on the vessel indicated different measurement accuracies. It is suggested for further studies that at least one GNSS antenna should be mounted above the mass center of the vessel to reduce the effects of the dominating pitch motion during the surveys. Numéro de notice : A2022-530 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1515/jogs-2022-0131 Date de publication en ligne : 23/06/2022 En ligne : https://doi.org/10.1515/jogs-2022-0131 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=101076
in Journal of geodetic science > vol 12 n° 1 (January 2022) . - pp 1 - 21[article]Spatiotemporal analysis of precipitable water vapor using ANFIS and comparison against voxel-based tomography and radiosonde / Mir Reza Ghaffari Razin in GPS solutions, vol 26 n° 1 (January 2022)
[article]
Titre : Spatiotemporal analysis of precipitable water vapor using ANFIS and comparison against voxel-based tomography and radiosonde Type de document : Article/Communication Auteurs : Mir Reza Ghaffari Razin, Auteur ; Samed Inyurt, Auteur Année de publication : 2022 Article en page(s) : n° 1 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] Inférence floue
[Termes IGN] modélisation spatio-temporelle
[Termes IGN] positionnement ponctuel précis
[Termes IGN] précipitation
[Termes IGN] radiosondage
[Termes IGN] retard troposphérique zénithal
[Termes IGN] station GPS
[Termes IGN] vapeur d'eau
[Termes IGN] voxelRésumé : (auteur) Water vapor (WV) is one of the most important parameters in meteorological studies. Using an adaptive neuro-fuzzy inference system (ANFIS), a new method has been proposed for spatiotemporal modeling of precipitable WV (PWV). In a first step, the tropospheric zenith wet delay (ZWD) is calculated using the observations of 23 GPS stations in the northwest of Iran. Out of these 23 stations, 21 stations for training and 2 stations for testing and validating were selected. The observations are for 15 days, ranging from day of year (DOY) 300 to 314 in 2011. The reason for choosing this area and time interval is the availability of a complete set of data. Then, the values of ZWD are converted to PWV. The PWV values obtained from this step are considered as the output of the ANFIS. Also, the latitude and longitude values of the GPS stations, the DOY, observational time (min), temperature (T), pressure (P), and relative humidity (RH) are considered input to ANFIS. The ANFIS network is trained using the back-propagation algorithm. After the training step, the PWV values are evaluated at 2 test stations, KLBR and GGSH, and at Tabriz radiosonde station (38.08° N, 46.28°E). For a more accurate evaluation, all the results of the new method are compared with the voxel-based tomography model. The evaluation of the results is performed using the relative error, standard deviation, correlation coefficient, and root-mean-square error (RMSE). Also, precise point positioning (PPP) is used to better evaluate the proposed model at test stations. The value of the correlation coefficient at the radiosonde station for the ANFIS and voxel is 0.90 and 0.87, respectively. Also, the minimum RMSE calculated for the ANFIS and voxel are 1.02 and 1.06 mm, respectively. In the PPP analysis, an improvement of about 4 mm is observed in the coordinates of the test stations using ANFIS. The results confirm the capability and high accuracy of the proposed model in determining the temporal and spatial variations of PWV. Numéro de notice : A2022-003 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s10291-021-01184-1 Date de publication en ligne : 19/10/2021 En ligne : https://doi.org/10.1007/s10291-021-01184-1 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=98828
in GPS solutions > vol 26 n° 1 (January 2022) . - n° 1[article]Baseline-dependent clock offsets in VLBI data analysis / Hana Krásná in Journal of geodesy, vol 95 n° 12 (December 2021)PermalinkIonospheric corrections tailored to the Galileo High Accuracy Service / Adria Rovira-Garcia in Journal of geodesy, vol 95 n° 12 (December 2021)PermalinkMetamorphic transformation rate over large spatial and temporal scales constrained by geophysical data and coupled modelling / Gyorgy Hetényl in Journal of metamorphic geology, vol 39 n° 9 (December 2021)PermalinkLe Mont-Blanc mesuré au LiDAR héliporté / Mathieu Peyréga in XYZ, n° 169 (décembre 2021)PermalinkThe method of detection and localization of configuration defects in geodetic networks by means of Tikhonov regularization / Roman Kadaj in Reports on geodesy and geoinformatics, vol 112 n° 1 (December 2021)PermalinkWhat is the impact of tectonic plate movement on country size? A long-term forecast / Kamil Maciuk in Remote sensing, vol 13 n° 23 (December-1 2021)PermalinkAccurate mapping method for UAV photogrammetry without ground control points in the map projection frame / Jianchen Liu in IEEE Transactions on geoscience and remote sensing, vol 59 n° 11 (November 2021)PermalinkEvaluation of global ocean tide models based on tidal gravity observations in China / Hongbo Tan in Geodesy and Geodynamics, vol 12 n° 6 (November 2021)PermalinkGeoid determination through the combined least-squares adjustment of GNSS/levelling/gravity networks – a case study in Linyi, China / Dongmei Guo in Survey review, Vol 53 n° 381 (November 2021)PermalinkMode N, an alternative positioning, navigation and timing system for aviation / Brandon Weaver in GPS world, vol 32 n° 11 (November 2021)Permalink