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Examining the influence of changing laser pulse repetition frequencies on conifer forest canopy returns / Laura Chasmer in Photogrammetric Engineering & Remote Sensing, PERS, vol 72 n° 12 (December 2006)
[article]
Titre : Examining the influence of changing laser pulse repetition frequencies on conifer forest canopy returns Type de document : Article/Communication Auteurs : Laura Chasmer, Auteur ; Christopher Hopkinson, Auteur ; et al., Auteur Année de publication : 2006 Article en page(s) : pp 1359 - 1367 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie
[Termes IGN] ALTM
[Termes IGN] canopée
[Termes IGN] données lidar
[Termes IGN] données multitemporelles
[Termes IGN] forêt boréale
[Termes IGN] fréquence
[Termes IGN] impulsion laser
[Termes IGN] lasergrammétrie
[Termes IGN] onde radioélectrique
[Termes IGN] Pinophyta
[Termes IGN] surface du sol
[Termes IGN] télémétrie laser aéroporté
[Termes IGN] vibrationRésumé : (Auteur) The distribution of laser pulses within conifer forest trees and canopies are examined by varying the rate of laser pulse emission and the inherent laser pulse properties (laser pulse energy, pulse width, pulse length, and roll-over or trigger time). In this study, an Optech, Inc. ALTM 3100 airborne lidar is used, emitting pulses at 50 kHz and 100 kHz, allowing for changes in laser pulse characteristics while also keeping all other survey parameters equal. We found that:
1. Pulses and associated characteristics emitted at 50 kHz penetrated further into the canopy than 100 kHz for a significant number of individual trees.
2. At tall tree plots with no understory, pulses emitted at 50 kHz penetrated further into the canopy than 100 kHz for a significant number of plots.
3. For plots with significant understory and shorter trees, pulses emitted at 100 kHz penetrated further into the canopy than 50 kHz. We suspect that this may be due, in part, to canopy openness.
Laser pulse energy and character differences associated with different laser pulse emission frequencies are likely a contributing factor in laser pulse penetration through the canopy to the ground surface. Efforts to understand laser pulse character influences on canopy returns are important as biomass and vegetation structure models derived from lidar are increasingly adopted. Copyright ASPRSNuméro de notice : A2006-544 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article DOI : 10.14358/PERS.72.12.1359 En ligne : https://doi.org/10.14358/PERS.72.12.1359 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28267
in Photogrammetric Engineering & Remote Sensing, PERS > vol 72 n° 12 (December 2006) . - pp 1359 - 1367[article]Evaluation of hyperspectral data for geological mapping / Muneendra Kumar in Geoinformatics, vol 9 n° 6 (01/09/2006)
[article]
Titre : Evaluation of hyperspectral data for geological mapping Type de document : Article/Communication Auteurs : Muneendra Kumar, Auteur ; T.N. Singh, Auteur Année de publication : 2006 Article en page(s) : pp 26 - 31 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] bande spectrale
[Termes IGN] carte géologique
[Termes IGN] cartographie géologique
[Termes IGN] fréquence
[Termes IGN] identification automatique
[Termes IGN] image hyperspectrale
[Termes IGN] minéralogie
[Termes IGN] réflectance spectrale
[Termes IGN] spectromètre imageur
[Termes IGN] surveillance géologiqueRésumé : (Auteur) Hyperspectral remote sensing, the measurements of the Earth's surface in up to hundreds of spectral images, provides a unique means of remotely mapping mineralogy. A wide variety of hyperspectral data are now available along with operational methods for quantitatively analysing the data and producing mineral maps. This paper is meant to illustrate the potential of these data and how it can be used as a tool to aid detailed geologic mapping and exploration. Copyright GEOinformatics Numéro de notice : A2006-386 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28110
in Geoinformatics > vol 9 n° 6 (01/09/2006) . - pp 26 - 31[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 262-06061 SL Revue Centre de documentation Revues en salle Disponible GNSS update: positive and negative developments / Huibert-Jan Lekkerkerk in Geoinformatics, vol 9 n° 5 (01/07/2006)
[article]
Titre : GNSS update: positive and negative developments Type de document : Article/Communication Auteurs : Huibert-Jan Lekkerkerk, Auteur Année de publication : 2006 Article en page(s) : pp 24 - 25 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] European Geostationary Navigation Overlay Service
[Termes IGN] fréquence
[Termes IGN] Galileo
[Termes IGN] Global Navigation Satellite System
[Termes IGN] Global Positioning System
[Termes IGN] GPS en mode différentiel
[Termes IGN] système de positionnement par satellites
[Termes IGN] Wide Area Augmentation SystemRésumé : (Auteur) In the past few months a lot has happened regarding the implementation and testing of new GNSS frequencies. Not all results are positive however, especially with GPS there are some items that warrant attention in the long(er) run. Furthermore critics of the Galileo program seem to be proven partially right when looking at the more recent developments of the program. But not all is amiss in the world of navigation. The EGNOS signal is scheduled to become operational soon and WAAS has been put to use on a new aviation level in the United States. Copyright Geoinformatics. Numéro de notice : A2006-315 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28039
in Geoinformatics > vol 9 n° 5 (01/07/2006) . - pp 24 - 25[article]Practical satellite navigation: part 5 system selection and applications / Huibert-Jan Lekkerkerk in Geoinformatics, vol 9 n° 5 (01/07/2006)
[article]
Titre : Practical satellite navigation: part 5 system selection and applications Type de document : Article/Communication Auteurs : Huibert-Jan Lekkerkerk, Auteur Année de publication : 2006 Article en page(s) : pp 54 - 57 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] fiabilité des données
[Termes IGN] fréquence
[Termes IGN] GPS en mode différentiel
[Termes IGN] interface utilisateur
[Termes IGN] récepteur GNSS
[Termes IGN] récepteur GPSRésumé : (Auteur) In the previous articles the (im)possibilities of satellite navigation systems were discussed. Some readers might have wondered why it is important to have this knowledge. In this article, I will try to discuss the selection of receivers based on a number of possible applications. Global knowledge of items discussed in the previous articles is necessary to fully appreciate this article. Copyright Geoinformatics. Numéro de notice : A2006-318 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28042
in Geoinformatics > vol 9 n° 5 (01/07/2006) . - pp 54 - 57[article]GPS + modernized GPS + Galileo signal timing biases / C. Hegarty in GPS world, vol 17 n° 3 (March 2006)
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Titre : GPS + modernized GPS + Galileo signal timing biases Type de document : Article/Communication Auteurs : C. Hegarty, Auteur ; E. Powers, Auteur ; B. Fonville, Auteur Année de publication : 2006 Article en page(s) : pp 49 - 54 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] analyse comparative
[Termes IGN] erreur systématique
[Termes IGN] fréquence
[Termes IGN] mesurage de pseudo-distance
[Termes IGN] polarisation
[Termes IGN] récepteur GPS
[Termes IGN] signal Galileo
[Termes IGN] signal GPS
[Termes IGN] système de positionnement par satellitesRésumé : (Editeur) GPS timing and navigation user solutions are based on pseudo-range measurements made by correlating user-receiver - generated replica signals broadcast by the GPS satellites. Any bias resulting from this correlation process within a user receiver tends to be common across all receiver channels when the signal characteristics - code type, modulation type and band-with - are identical. Such common biases will cancel out in the user navigation solution and appear as a fixed bias for timing solutions and some atmospheric signal analyses. New GPS signals and the future Galileo signals are somewhat different than the legacy signals broadcast by GPS satellites today, so new ways of accounting for biases will be needed. In this month's column, Chris Hegarty, Ed powers and Blair Fonville discuss this problem and quantify the timing biases of the different legacy and modernized GPS and Galileo signals broadcast on the L1 frequency and their dependencies on factors such as user-receiver filter band-with, filter transfer function and delay-locked loop correlator spacing. Numéro de notice : A2006-083 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=27810
in GPS world > vol 17 n° 3 (March 2006) . - pp 49 - 54[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 067-06031 RAB Revue Centre de documentation En réserve L003 Disponible Naviguer dans le monde sans fil : un aperçu de l'influence exercée par la technologie sans fil sur les topographes / N. Pugh in XYZ, n° 104 (septembre - novembre 2005)PermalinkGalileo frequency and signal design / Günter W. Hein in GPS world, vol 14 n° 6 (June 2003)PermalinkPermalinkNew IGS clock products: a global time transfer assessment / Jim Ray in GPS world, vol 13 n° 11 (November 2002)PermalinkLand cover classification models using Shuttle Imaging Radar (SIR-C) data: a case study in New Hampshire, USA / R. Narayanan in Geocarto international, vol 17 n° 3 (September - November 2002)PermalinkVariation in point positioning accuracies for single frequency GPS users during solar maximum / S. Skone in Geomatica, vol 56 n° 2 (June 2002)PermalinkAirborne gravity mesasurements using a LaCoste & Romberg air-sea gravity meter / Alain Geiger (2002)PermalinkEtudes des matrices de Butler (note technique du comité de compétence technique "électromagnétisme" n°1) / I. Albert (2002)PermalinkGalileo defined: proposed architecture and services for the new European satellite positioning system / L. Tytgat in GPS world, vol 12 n° 9 (September 2001)PermalinkRapport de la 22ème session (septembre 2000) / Comité consultatif d'électricité et magnétisme (2001)Permalink