Détail de l'auteur
Auteur Q. Chen |
Documents disponibles écrits par cet auteur (3)
Ajouter le résultat dans votre panier
Visionner les documents numériques
Affiner la recherche Interroger des sources externes
Singular spectrum analysis for modeling seasonal signals from GPS time series / Q. Chen in Journal of geodynamics, vol 72 (December 2013)
[article]
Titre : Singular spectrum analysis for modeling seasonal signals from GPS time series Type de document : Article/Communication Auteurs : Q. Chen, Auteur ; Tonie M. van Dam, Auteur ; Nico Sneeuw, Auteur ; Xavier Collilieux , Auteur ; M. Weigelt, Auteur ; Paul Rebischung , Auteur Année de publication : 2013 Article en page(s) : pp 25 - 35 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] analyse spectrale
[Termes IGN] compensation par moindres carrés
[Termes IGN] filtre de Kalman
[Termes IGN] matrice de covariance
[Termes IGN] série temporelle
[Termes IGN] signal GPS
[Termes IGN] variation saisonnière
[Vedettes matières IGN] Traitement de données GNSSRésumé : (auteur) Seasonal signals in GPS time series are of great importance for understanding the evolution of regional mass fluctuations, i.e., ice, hydrology, and ocean mass. Conventionally these signals (quasi-annual and semi-annual signals) are modeled by least-squares fitting harmonic terms with a constant amplitude and phase. In reality, however, such seasonal signals are modulated, i.e., they will have a time-variable amplitude and phase. Recently, Davis et al. (2012) proposed a Kalman filter based approach to capture the stochastic seasonal behavior of geodetic time series. Singular Spectrum Analysis (SSA) is a non-parametric method, which uses time domain data to extract information from short and noisy time series without a priori knowledge of the dynamics affecting the time series. A prominent benefit is that trends obtained in this way are not necessarily linear. Further, true oscillations can be amplitude and phase modulated. In this work, we will assess the value of SSA for extracting time-variable seasonal signals from GPS time series. We compare our SSA-based results to those obtained using (1) least-squares analysis and (2) Kalman filtering. Our results demonstrate that SSA is a viable and complementary tool for extracting modulated oscillations from GPS time series. Numéro de notice : A2013-512 Affiliation des auteurs : LASTIG LAREG+Ext (2012-mi2018) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.jog.2013.05.005 Date de publication en ligne : 28/06/2013 En ligne : http://dx.doi.org/10.1016/j.jog.2013.05.005 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=80232
in Journal of geodynamics > vol 72 (December 2013) . - pp 25 - 35[article]Combined use of Quickbird and lidar data for mapping a urban environment / N.B. Da Luz in Revue Française de Photogrammétrie et de Télédétection, n° 198 - 199 (Septembre 2012)
[article]
Titre : Combined use of Quickbird and lidar data for mapping a urban environment Type de document : Article/Communication Auteurs : N.B. Da Luz, Auteur ; D.J. Dos Santos, Auteur ; A.L. De Mendonça, Auteur ; A.F. Buffara Antunes, Auteur ; H. Araki, Auteur ; Q. Chen, Auteur Année de publication : 2012 Article en page(s) : pp 78 - 87 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications photogrammétriques
[Termes IGN] carte d'occupation du sol
[Termes IGN] cartographie urbaine
[Termes IGN] classification par arbre de décision
[Termes IGN] données lidar
[Termes IGN] données localisées 3D
[Termes IGN] image Quickbird
[Termes IGN] milieu urbain
[Termes IGN] modèle numérique de surface
[Termes IGN] Parana (Brésil)
[Termes IGN] segmentation d'image
[Termes IGN] semis de pointsRésumé : (Auteur) High resolution satellite imagery and airborne Lidar data can characterize the earth surface with unprecedented details in spatial and structure information, respectively. However, most studies have used them separately instead of in combination for land surface mapping. Considering their highly complementary nature, it is critical to investigate whether and how the integration of both can improve the accuracy of land cover and land use (LCLU) mapping. This study explored the use of Quickbird imagery and airborne Lidar data for mapping a complex urban environment in the City of Curitiba, Parana State, Southern Brazil, which is composed of secondary shrub vegetation, grass and climax primary Araucaria forests combined with urban objects such as roads and buildings. Airborne Lidar data were processed to generate DEM, DSM (Digital Surface Model), and DHM (Digital Height Model). The DSM generated from Lidar data were used to orthorectify Quickbird image with photogrammetric skills. A large number of metrics are generated from Lidar DHM, Lidar point cloud, Lidar intensity, and Quickbird imagery using object oriented segmentation approaches. Due to their power in handling non-parametric data, decision-tree based approaches were chosen to select the most relevant metrics and build rules for classification. It was found that the fusion of both types of data with decision trees increased the accuracy by 5 to 15% and resulted in an overall accuracy over 90%. Taking into account the increasing accessibility of Quickbird and airborne Lidar data, it is expected the methodology developed in this study has profound impacts in shifting our current paradigm in LCLU mapping. Numéro de notice : A2012-427 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31873
in Revue Française de Photogrammétrie et de Télédétection > n° 198 - 199 (Septembre 2012) . - pp 78 - 87[article]Assessment of terrain elevation derived from satellite laser altimetry over mountainous forest areas using airborne lidar data / Q. Chen in ISPRS Journal of photogrammetry and remote sensing, vol 65 n° 1 (January - February 2010)
[article]
Titre : Assessment of terrain elevation derived from satellite laser altimetry over mountainous forest areas using airborne lidar data Type de document : Article/Communication Auteurs : Q. Chen, Auteur Année de publication : 2010 Article en page(s) : pp 111 - 122 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie
[Termes IGN] décomposition de Gauss
[Termes IGN] données altimétriques
[Termes IGN] données ICEsat
[Termes IGN] données lidar
[Termes IGN] forêt
[Termes IGN] modèle numérique de surface
[Termes IGN] montagneRésumé : (Auteur) Gaussian decomposition has been used to extract terrain elevation from waveforms of the satellite lidar GLAS (Geoscience Laser Altimeter System), on board ICESat (Ice, Cloud, and land Elevation Satellite). The common assumption is that one of the extracted Gaussian peaks, especially the lowest one, corresponds to the ground. However, Gaussian decomposition is usually complicated due to the broadened signals from both terrain and objects above over sloped areas. It is a critical and pressing research issue to quantify and understand the correspondence between Gaussian peaks and ground elevation. This study uses not, vert, similar2000 km2 airborne lidar data to assess the lowest two GLAS Gaussian peaks for terrain elevation estimation over mountainous forest areas in North Carolina. Airborne lidar data were used to extract not only ground elevation, but also terrain and canopy features such as slope and canopy height. Based on the analysis of a total of not, vert, similar500 GLAS shots, it was found that (1) the lowest peak tends to underestimate ground elevation; terrain steepness (slope) and canopy height have the highest correlation with the underestimation, (2) the second to the lowest peak is, on average, closer to the ground elevation over mountainous forest areas, and (3) the stronger peak among the lowest two is closest to the ground for both open terrain and mountainous forest areas. It is expected that this assessment will shed light on future algorithm improvements and/or better use of the GLAS products for terrain elevation estimation. Numéro de notice : A2010-234 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2009.09.004 En ligne : https://doi.org/10.1016/j.isprsjprs.2009.09.004 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30428
in ISPRS Journal of photogrammetry and remote sensing > vol 65 n° 1 (January - February 2010) . - pp 111 - 122[article]Réservation
Réserver ce documentExemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 081-2010011 SL Revue Centre de documentation Revues en salle Disponible