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Wavelet-like denoising of GNSS data through machine learning. Application to the time series of the Campi Flegrei volcanic area (Southern Italy) / Rolando Carbonari in Geomatics, Natural Hazards and Risk, vol 14 n° 1 (2023)  

Public [article]  inGeomatics, Natural Hazards and Risk > vol 14 n° 1 (2023) . - n° 2187271 Titre : Wavelet-like denoising of GNSS data through machine learning. Application to the time series of the Campi Flegrei volcanic area (Southern Italy) Type de document : Article/Communication Auteurs : Rolando Carbonari, Auteur ; Umberto Riccardi, Auteur ; Prospero De Martino, Auteur ; et al., Auteur Année de publication : 2023 Article en page(s) : n° 2187271 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] caldeira [Termes IGN] classification par réseau neuronal convolutif [Termes IGN] déformation de la croute terrestre [Termes IGN] données GNSS [Termes IGN] filtrage du bruit [Termes IGN] Naples [Termes IGN] relief volcanique [Termes IGN] risque naturel [Termes IGN] série temporelle [Termes IGN] surveillance géologique [Termes IGN] transformation en ondelettes Résumé : (auteur) The great potential of the Global Navigation Satellite System (GNSS) in monitoring ground deformation is widely recognized. As with other geophysical data, GNSS time series can be significantly noisy, hiding elusive ground deformation signals. Several denoising techniques have been proposed to improve the signal-to-noise ratio over the years. One of the most effective denoising techniques has been proved to be multi-resolution decomposition through the discrete wavelet transform. However, wavelet analysis requires long data sets to be effective, as well as long computation times, that hinder its use as a real or near real-time monitoring tool. We propose training by a Convolutional Neural Network (CNN) to perform the equivalent of wavelet analysis to overcome these limitations. Once trained, the CNN model provides answers within seconds, making it feasible as a real-time data analysis tool. Our Machine Learning algorithm is tested on daily GNSS time series collected in the Campi Flegrei caldera (Southern Italy), which is a highly volcanic risk area. Without significant gaps, the retrieved RMSE and R2 values vary in the ranges 0.65–0.98 and 0.06–0.52 cm, respectively. These results are encouraging, as they hint at the possibility of applying this methodology in more effective real-time monitoring solutions for active volcanoes. Numéro de notice : A2023-180 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1080/19475705.2023.2187271 Date de publication en ligne : 10/03/2023 En ligne : https://doi.org/10.1080/19475705.2023.2187271 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=102949 [article]

Radial interpolation of GPS and leveling data of ground deformation in a resurgent caldera: application to Campi Flegrei (Italy) / Andrea Bevilacqua in Journal of geodesy, vol 94 n°2 (February 2020)  

Public [article]  inJournal of geodesy > vol 94 n°2 (February 2020) Titre : Radial interpolation of GPS and leveling data of ground deformation in a resurgent caldera: application to Campi Flegrei (Italy) Type de document : Article/Communication Auteurs : Andrea Bevilacqua, Auteur ; Augusto Neri, Auteur ; Prospero De Martino, Auteur ; et al., Auteur Année de publication : 2020 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications [Termes IGN] analyse diachronique [Termes IGN] caldeira [Termes IGN] Campanie (Italie) [Termes IGN] déformation horizontale de la croute terrestre [Termes IGN] déformation verticale de la croute terrestre [Termes IGN] données géodésiques [Termes IGN] données GPS [Termes IGN] fonction de base radiale [Termes IGN] image radar moirée [Termes IGN] interféromètrie par radar à antenne synthétique [Termes IGN] interpolation [Termes IGN] modèle de déformation tectonique [Termes IGN] régression linéaire [Termes IGN] réseau de nivellement [Termes IGN] surveillance géologique [Termes IGN] volcan Résumé : (auteur) This study presents a new method, called the Radial Interpolation Method, to interpolate data characterized by an approximately radial pattern around a relatively constrained central zone, such as the ground deformation patterns shown in many active volcanic areas. The method enables the fast production of short-term deformation maps on the base of spatially sparse ground deformation measurements and can provide uncertainty quantification on the interpolated values, fundamental for hazard assessment purposes and deformation source reconstruction. The presented approach is not dependent on a priori assumptions about the geometry, location and physical properties of the source, except for the requirement of a locally radial pattern, i.e., allowing multiple centers of symmetry. We test the new method on a synthetic point source example, and then, we apply the method to selected time intervals of real geodetic data collected at the Campi Flegrei caldera during the last 39 years, including examples of leveling, Geodetic Precise Traversing measurements and Global Positioning System. The maps of horizontal displacement, calculated inland, show maximum values lying along a semicircular annular region with a radius of about 2–3 km in size. This semi-annular area is marked by mesoscale structures such as faults, sand dikes and fractures. The maps of vertical displacement describe a linear relation between the maximum vertical uplift measured and the volume variation. The multiplicative factor in the linear relation is about 0.3 × 106 m3/cm if we estimate the proportion of the ΔV that is captured by the GPS network onland and we use this to estimate the full ΔV. In this case, the 95% confidence interval on K because of linear regression is ± 5%. Finally, we briefly discuss how the new method could be used for the production of short-term vent opening maps on the base of real-time geodetic measurements of the horizontal and vertical displacements. Numéro de notice : A2020-152 Affiliation des auteurs : non IGN Thématique : IMAGERIE/POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-020-01355-x Date de publication en ligne : 05/02/2020 En ligne : https://doi.org/10.1007/s00190-020-01355-x Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=94785 [article]

A new method for specular and diffuse pseudorange multipath error extraction using wavelet analysis / Giovanni Pugliano in GPS solutions, vol 20 n° 3 (July 2016)  

Public [article]  inGPS solutions > vol 20 n° 3 (July 2016) . - pp 499 - 508 Titre : A new method for specular and diffuse pseudorange multipath error extraction using wavelet analysis Type de document : Article/Communication Auteurs : Giovanni Pugliano, Auteur ; Umberto Robustelli, Auteur ; Fabio Rossi, Auteur ; Raffaele Santamaria, Auteur Année de publication : 2016 Article en page(s) : pp 499 - 508 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] Campanie (Italie) [Termes IGN] correction du trajet multiple [Termes IGN] mesurage de pseudo-distance [Termes IGN] onde porteuse [Termes IGN] réflexion spéculaire [Termes IGN] transformation en ondelettes [Vedettes matières IGN] Traitement de données GNSS Résumé : (Auteur) Multipath remains one of the major challenges in Global Navigation Satellite System (GNSS) positioning because it is considered the dominant source of ranging errors, which can be classified into specular and diffuse types. We present a new method using wavelets to extract the pseudorange multipath in the time domain and breaking it down into the two components. The main idea is an analysis-reconstruction approach based on application of both continuous wavelet transform (CWT) and discrete wavelet transform (DWT). The proposed procedure involves the use of L1 code-minus-carrier (CMC) observable where higher-frequency terms are isolated as residuals. CMC residuals are analyzed by applying the CWT, and we propose the scalogram as a technique for discerning time–frequency variations of the multipath signal. Unlike Fourier transform, the potential of the CWT scalogram for examining the non-stationary and multifrequency nature of the multipath is confirmed as it simultaneously allows fine detection and time localization of the most representative frequencies of the signal. This interpretation of the CWT scalogram is relevant when choosing the levels of reconstruction with DWT, allowing accurate time domain extraction of both the specular and diffuse multipath. The performance and robustness of the method and its boundary applicability are assessed. The experiment was carried out using a receiver of Campania GNSS Network. The results are given in which specular multipath error is achieved using DWT level 7 approximation component and diffuse multipath error is achieved using DWT level 6 denoised detail component. Numéro de notice : A2016-634 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1007/s10291-015-0458-0 En ligne : http://dx.doi.org/10.1007/s10291-015-0458-0 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81838 [article]

From previous C-Band to new X-band SAR systems : Assessment of the DInSAR mapping improvement for deformation time-series retrieval in urban areas / Manuela Bonano in IEEE Transactions on geoscience and remote sensing, vol 51 n° 4 Tome 1 (April 2013)  

Public [article]  inIEEE Transactions on geoscience and remote sensing > vol 51 n° 4 Tome 1 (April 2013) . - pp 1973 - 1984 Titre : From previous C-Band to new X-band SAR systems : Assessment of the DInSAR mapping improvement for deformation time-series retrieval in urban areas Type de document : Article/Communication Auteurs : Manuela Bonano, Auteur ; Michele Manunta, Auteur ; et al., Auteur Année de publication : 2013 Article en page(s) : pp 1973 - 1984 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications [Termes IGN] analyse comparative [Termes IGN] bande C [Termes IGN] bande X [Termes IGN] déformation d'édifice [Termes IGN] image Cosmo-Skymed [Termes IGN] image Envisat [Termes IGN] image radar moirée [Termes IGN] image Radarsat [Termes IGN] interferométrie différentielle [Termes IGN] interféromètrie par radar à antenne synthétique [Termes IGN] Naples [Termes IGN] série temporelle [Termes IGN] zone urbaine Résumé : (Auteur) We investigate the capability improvement of the advanced differential interferometric synthetic aperture radar (DInSAR) techniques to map deformation phenomena affecting urban areas by exploiting multitemporal SAR data acquired by the new X-band sensors with respect to those of the previous C-band systems. In particular, we perform a comparative analysis of the deformation time-series retrieved by applying the full-resolution Small BAseline Subset DInSAR technique to selected sequences of SAR data acquired by the ENVISAT and RADARSAT-1 sensors (both operating at C-band) and by the X-band radar systems onboard the SAR sensors of the COSMO-SkyMed (CSK) constellation. This study, focused on the city of Napoli (Italy), allows us to quantify the dramatic increase of the DInSAR coherent pixel density achieved by exploiting the high-resolution X-band CSK SAR images (a few meters), resulting in an improvement factor of about 320% and 550%, with respect to the RADARSAT-1 and ENVISAT products, respectively. This improvement permits us to analyze nearly all the structures located within the investigated urbanized area and, in many cases, also portions of the same building. The improved coherent pixel spatial densities, combined with the reduced revisit times of the new X-band SAR missions, allow us to significantly increase the effectiveness of the advanced DInSAR methodologies, further extending the role of those Earth Observation data in the development of monitoring scenarios. Numéro de notice : A2013-212 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2012.2215332 En ligne : https://doi.org/10.1109/TGRS.2012.2215332 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32350 [article]

The first terrestrial laser scanner application over Vesuvius: High resolution model of a volcano crater / Arianna Pesci in International Journal of Remote Sensing IJRS, vol 28 n° 1-2 (January 2007)  

Public [article]  inInternational Journal of Remote Sensing IJRS > vol 28 n° 1-2 (January 2007) . - pp 203 - 219 Titre : The first terrestrial laser scanner application over Vesuvius: High resolution model of a volcano crater Type de document : Article/Communication Auteurs : Arianna Pesci, Auteur ; F. Loddo, Auteur ; D. Conforti, Auteur Année de publication : 2007 Article en page(s) : pp 203 - 219 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image [Termes IGN] cratère [Termes IGN] modèle numérique de surface [Termes IGN] Naples [Termes IGN] réflectance [Termes IGN] réflectance spectrale [Termes IGN] surveillance géologique [Termes IGN] télémétrie laser terrestre [Termes IGN] Vésuve (volcan) [Termes IGN] volcan Résumé : (Auteur) This paper deals with terrestrial long-range laser scanner applications, gives an overview of topics related to this methodology, provides real and tested information about laser scanners, and analyses the reflectance of different materials. After positive results obtained during an experimental test executed in Bologna (Italy) on March 2005, the INGV (Bologna, Italy) and CODEVINTEC srl (Milan, Italy) planned a mission over the Mount Vesuvius volcano (Naples, Italy). For the first time, a wide crater area composed of low reflectivity materials was completely surveyed, creating a very accurate digital surface model. In this work, a long-range laser scanner was used to create high-precision surveys that demonstrated very low residual values in scan comparisons. The results lead to the conclusion that this methodology is suitable for surface monitoring proposals. Copyright Taylor & Francis Numéro de notice : A2007-035 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/01431160500534473 En ligne : https://doi.org/10.1080/01431160500534473 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28401 [article]

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Les politiques de déplacement urbain en quête d'innovations / B. Jouve (2002)

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Détection des cadastres antiques par filtrage optique : Gaule et Campanile / François Favory in Mélanges de l'école française de Rome - Antiquité MEFRA, vol 1980 n° 1 Tome 92 (01/01/1980)

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