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A phase-altimetric simulator : studying the sensitivity of Earth-reflected GNSS signals to ocean topography / Aaron Maximilian Semmling in IEEE Transactions on geoscience and remote sensing, vol 54 n° 11 (November 2016)
[article]
Titre : A phase-altimetric simulator : studying the sensitivity of Earth-reflected GNSS signals to ocean topography Type de document : Article/Communication Auteurs : Aaron Maximilian Semmling, Auteur ; Vera Leister, Auteur ; Jan Saynisch, Auteur ; et al., Auteur Année de publication : 2016 Article en page(s) : pp 6791 - 6802 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] altimétrie
[Termes IGN] analyse de sensibilité
[Termes IGN] océanographie spatiale
[Termes IGN] positionnement par GNSS
[Termes IGN] réflectométrie par GNSS
[Termes IGN] signal GNSS
[Termes IGN] surface de la merRésumé : (Auteur) This paper presents a simulation study on Global Navigation Satellite System (GNSS) reflections focusing on a phase altimetric method for ocean topography retrieval. It examines carrier phase residuals of Earth-reflected GNSS signals in preparation for the GNSS Reflectometry Radio Occultation and Scatterometry experiment aboard the International Space Station (GEROS-ISS). The residuals' sensitivity to ocean topography (maximum of 2-m amplitude variation of global sea level) is shown. A trigonometric approach to determine the specular reflection point is proposed. Reflection events are simulated assuming different low Earth orbit receivers and GNSS-type transmitters. Suitable events for phase altimetry are assumed between 5° and 30° elevation lasting between 10 and 15 min with ground tracks length of > 3000 km. Typical along-track footprints (1 s integration time) have a length of about 5 km. Within the assumed elevation range the coherent footprint ellipse has a major axis between 1 and 6 km. A Master-Slave sampling is proposed to approximate large-scale delay and Doppler variations of the reflected signal (Slave channel) relative to the direct signal (Master channel). Slave residuals of an example event are simulated to retrieve a small-scale phase delay for ocean topography inversion. The signal-to-noise ratio restricts the quality of the topography results. Height precision on sub-decimeter level for 30-dB SNR is degraded up to a meter level for 20-dB SNR. Ionosphere-free linear combination allows keeping the precision level. Troposphere refraction degrades precision particularly at the low elevation limit. Precision improves toward higher elevations. The tolerance to ocean roughness decreases in the same way. Numéro de notice : A2016-918 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2016.2591065 En ligne : http://dx.doi.org/10.1109/TGRS.2016.2591065 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=83147
in IEEE Transactions on geoscience and remote sensing > vol 54 n° 11 (November 2016) . - pp 6791 - 6802[article]The weight matrix determination of systematic bias calibration for a laser altimeter / Ma Yue in Photogrammetric Engineering & Remote Sensing, PERS, vol 82 n° 11 (November 2016)
[article]
Titre : The weight matrix determination of systematic bias calibration for a laser altimeter Type de document : Article/Communication Auteurs : Ma Yue, Auteur ; Li Song, Auteur ; Lu Xiushan, Auteur ; et al., Auteur Année de publication : 2016 Article en page(s) : pp 847 - 852 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie
[Termes IGN] données ICEsat
[Termes IGN] erreur de mesure
[Termes IGN] étalonnage
[Termes IGN] géolocalisation
[Termes IGN] incertitude de mesurage
[Termes IGN] matrice
[Termes IGN] matrice d'erreurRésumé : (Auteur) The geolocation accuracy of satellite laser altimeters is significantly influenced by on-orbit misalignment and ranging biases. Few researchers have investigated the weight matrix determination method, which plays a critical role in bias estimation. In this article, a systematic misalignment and ranging bias model was deduced. Based on the least squares criterion, a bias calibration method was designed for use with solid natural surfaces; and the weight matrix was defined according to the ranging uncertainty theory. Referring to the Geoscience Laser Altimeter System (glas) parameters, the established model and method were verified using programming simulations, which indicated with a misalignment of tens of arc-seconds in the pitch and roll directions and a ranging bias of several centimeters, by using the weight matrix, the estimation accuracies of the misalignment and ranging bias increased by 0.22 and 2 cm, respectively. Consequently, the geolocation accuracy increased by approximately 0.64 m horizontally and 3 cm vertically for a 1° sloping surface. Numéro de notice : A2016-944 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.14358/PERS.82.11.847 En ligne : http://dx.doi.org/10.14358/PERS.82.11.847 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=83436
in Photogrammetric Engineering & Remote Sensing, PERS > vol 82 n° 11 (November 2016) . - pp 847 - 852[article]Aboveground biomass mapping in French Guiana by combining remote sensing, forest inventories and environmental data / Ibrahim Fayad in International journal of applied Earth observation and geoinformation, vol 52 (October 2016)
[article]
Titre : Aboveground biomass mapping in French Guiana by combining remote sensing, forest inventories and environmental data Type de document : Article/Communication Auteurs : Ibrahim Fayad, Auteur ; Nicolas Baghdadi, Auteur ; Stéphane Guitet , Auteur ; Jean-Stéphane Bailly, Auteur ; Bruno Hérault, Auteur ; Valéry Gond, Auteur ; Mahmoud El-Hajj, Auteur ; Ho Tong Minh Dinh, Auteur Année de publication : 2016 Article en page(s) : pp 502 - 514 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] biomasse aérienne
[Termes IGN] données environnementales
[Termes IGN] données ICEsat
[Termes IGN] forêt tropicale
[Termes IGN] Guyane (département français)
[Termes IGN] inventaire forestier national (données France)
[Termes IGN] régressionRésumé : (auteur) Mapping forest aboveground biomass (AGB) has become an important task, particularly for the reporting of carbon stocks and changes. AGB can be mapped using synthetic aperture radar data (SAR) or passive optical data. However, these data are insensitive to high AGB levels (>150 Mg/ha, and >300 Mg/ha for P-band), which are commonly found in tropical forests. Studies have mapped the rough variations in AGB by combining optical and environmental data at regional and global scales. Nevertheless, these maps cannot represent local variations in AGB in tropical forests. In this paper, we hypothesize that the problem of misrepresenting local variations in AGB and AGB estimation with good precision occurs because of both methodological limits (signal saturation or dilution bias) and a lack of adequate calibration data in this range of AGB values. We test this hypothesis by developing a calibrated regression model to predict variations in high AGB values (mean >300 Mg/ha) in French Guiana by a methodological approach for spatial extrapolation with data from the optical geoscience laser altimeter system (GLAS), forest inventories, radar, optics, and environmental variables for spatial inter- and extrapolation. Given their higher point count, GLAS data allow a wider coverage of AGB values. We find that the metrics from GLAS footprints are correlated with field AGB estimations (R2 = 0.54, RMSE = 48.3 Mg/ha) with no bias for high values. First, predictive models, including remote-sensing, environmental variables and spatial correlation functions, allow us to obtain “wall-to-wall” AGB maps over French Guiana with an RMSE for the in situ AGB estimates of ∼50 Mg/ha and R2 = 0.66 at a 1-km grid size. We conclude that a calibrated regression model based on GLAS with dependent environmental data can produce good AGB predictions even for high AGB values if the calibration data fit the AGB range. We also demonstrate that small temporal and spatial mismatches between field data and GLAS footprints are not a problem for regional and global calibrated regression models because field data aim to predict large and deep tendencies in AGB variations from environmental gradients and do not aim to represent high but stochastic and temporally limited variations from forest dynamics. Thus, we advocate including a greater variety of data, even if less precise and shifted, to better represent high AGB values in global models and to improve the fitting of these models for high values. Numéro de notice : A2016--202 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article DOI : 10.1016/j.jag.2016.07.015 Date de publication en ligne : 01/08/2016 En ligne : https://doi.org/10.1016/j.jag.2016.07.015 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96037
in International journal of applied Earth observation and geoinformation > vol 52 (October 2016) . - pp 502 - 514[article]Multi-technique combination of space geodesy observations: Impact of the Jason-2 satellite on the GPS satellite orbits estimation / Myriam Zoulida in Advances in space research, vol 58 n° 7 (October 2016)
[article]
Titre : Multi-technique combination of space geodesy observations: Impact of the Jason-2 satellite on the GPS satellite orbits estimation Type de document : Article/Communication Auteurs : Myriam Zoulida , Auteur ; Arnaud Pollet , Auteur ; David Coulot , Auteur ; Félix Perosanz, Auteur ; Sylvain Loyer, Auteur ; Richard Biancale, Auteur ; Paul Rebischung , Auteur Année de publication : 2016 Article en page(s) : pp 1376 - 1389 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] données Jason
[Termes IGN] orbitographie
[Termes IGN] satellite GPS
[Vedettes matières IGN] Traitement de données GNSSRésumé : (auteur) In order to improve the Precise Orbit Determination (POD) of the GPS constellation and the Jason-2 Low Earth Orbiter (LEO), we carry out a simultaneous estimation of GPS satellite orbits along with Jason-2 orbits, using GINS software. Along with GPS station observations, we use Jason-2 GPS, SLR and DORIS observations, over a data span of 6 months (28/05/2011–03/12/2011). We use the Geophysical Data Records-D (GDR-D) orbit estimation standards for the Jason-2 satellite. A GPS-only solution is computed as well, where only the GPS station observations are used. It appears that adding the LEO GPS observations results in an increase of about 0.7% of ambiguities fixed, with respect to the GPS-only solution. The resulting GPS orbits from both solutions are of equivalent quality, agreeing with each other at about 7 mm on Root Mean Square (RMS). Comparisons of the resulting GPS orbits to the International GNSS Service (IGS) final orbits show the same level of agreement for both the GPS-only orbits, at 1.38 cm in RMS, and the GPS + Jason2 orbits at 1.33 cm in RMS. We also compare the resulting Jason-2 orbits with the 3-technique Segment Sol multi-missions d’ALTimétrie, d’orbitographie et de localisation précise (SSALTO) POD products. The orbits show good agreement, with 2.02 cm of orbit differences global RMS, and 0.98 cm of orbit differences RMS on the radial component. Numéro de notice : A2016-963 Affiliation des auteurs : LASTIG LAREG+Ext (2012-mi2018) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.asr.2016.06.019 Date de publication en ligne : 22/06/2016 En ligne : http://dx.doi.org/10.1016/j.asr.2016.06.019 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=83580
in Advances in space research > vol 58 n° 7 (October 2016) . - pp 1376 - 1389[article]The influence of elliptical Gaussian laser beam on inversion of terrain information for satellite laser altimeter / Zhou Hui in Photogrammetric Engineering & Remote Sensing, PERS, vol 82 n° 10 (October 2016)
[article]
Titre : The influence of elliptical Gaussian laser beam on inversion of terrain information for satellite laser altimeter Type de document : Article/Communication Auteurs : Zhou Hui, Auteur ; Li Song, Auteur ; Yang Chi, Auteur Année de publication : 2016 Article en page(s) : pp 767 - 773 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] données ICEsat
[Termes IGN] erreur de positionnement
[Termes IGN] fonction inverse
[Termes IGN] modèle mathématique
[Termes IGN] récepteur radar
[Termes IGN] signalRésumé : (Auteur) The transmitted laser mode of Geosciences Laser Altimeter System (GLAS) is a significant factor in determining the received pulse waveforms, which are used for inversing target information. The inversion algorithms in the scientific literature are based on the assumption that the transmitted laser is circular Gaussian. The practical laser pattern of GLAS is not circularly symmetric, but elliptical Gaussian. The received pulse shape will contain a bias, which would cause an error in the inversion information. In this paper, we describe new theoretical models about received pulse signal and inversion errors of range, surface slope and roughness. We present the results of waveforms shape and inversion errors for three representative terrains with different surface slope and roughness. The results show that the maximal inversion errors of range, surface slope, and roughness will reach 24.25 cm, 8.82° and 4.58 m, respectively, which cannot be negligible. Therefore, the inversion information should be reevaluated and amended depending on the type of terrain. Numéro de notice : A2016-933 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.14358/PERS.82.10.767 En ligne : http://dx.doi.org/10.14358/PERS.82.10.767 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=83347
in Photogrammetric Engineering & Remote Sensing, PERS > vol 82 n° 10 (October 2016) . - pp 767 - 773[article]GNSS interferometric radio occultation / Manuel Martín-Neira in IEEE Transactions on geoscience and remote sensing, vol 54 n° 9 (September 2016)PermalinkIndispensables encrages de l'altimétrie / Michel Kasser in Géomètre, n° 2139 (septembre 2016)PermalinkLa mission Topex-Poséidon d'altimétrie spatiale / Anonyme in Géomètre, n° 2139 (septembre 2016)PermalinkL’évolution du niveau de la mer / Alain Coulomb in Naturellement, n° 122 (Juin 2016)PermalinkGeneration of highly accurate digital elevation models with unmanned aerial vehicles / Yuriy Reshetyuk in Photogrammetric record, vol 31 n° 154 (June - August 2016)PermalinkEvaluating the use of GPS heights in water conservation applications / Ahmed F. Elaksher in Survey review, vol 48 n° 348 (May 2016)PermalinkICESat/GLAS canopy height sensitivity inferred from Airborne Lidar / Craig Mahoney in Photogrammetric Engineering & Remote Sensing, PERS, vol 82 n° 5 (May 2016)PermalinkForest above ground biomass inversion by fusing GLAS with optical remote sensing data / Xiaohuan Xi in ISPRS International journal of geo-information, vol 5 n° 4 (April 2016)PermalinkSonel surveille la mer / Marielle Mayo in Géomètre, n° 2135 (avril 2016)PermalinkRegional scale rain-forest height mapping using regression-kriging of spaceborne and airborne Lidar data: application on French Guiana / Ibrahim Fayad in Remote sensing, vol 8 n° 3 (March 2016)Permalink