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Entwicklung und Erprobung eines abbildenden Laseraltimeters für den Flugeinsatz unter Verwendung des Mehrfrequenz- Phasenvergleichsverfahrens / C. Hug (1996)
Titre : Entwicklung und Erprobung eines abbildenden Laseraltimeters für den Flugeinsatz unter Verwendung des Mehrfrequenz- Phasenvergleichsverfahrens Titre original : [Élaboration et expérimentation d'un altimètre laser pour l'intervention en vol en utilisant des procédés multifréquence-phases différentes] Type de document : Thèse/HDR Auteurs : C. Hug, Auteur Editeur : Munich : Bayerische Akademie der Wissenschaften Année de publication : 1996 Collection : DGK - C Sous-collection : Dissertationen num. 457 Importance : 122 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-7696-9500-7 Note générale : Bibliographie Langues : Allemand (ger) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s)
[Termes IGN] altimètre laser
[Termes IGN] faisceau laser
[Termes IGN] lasergrammétrie
[Termes IGN] phase
[Termes IGN] télémètre laser aéroporté
[Termes IGN] télémétrie laser aéroportéIndex. décimale : 35.10 Acquisition d'images Résumé : (Auteur)This paper investigates the usefulness of the principle of multi-frequency sidetone ranging for three-dimensional airborne terrain survey. The potential and the limits for scanning laser altimeters using this ranging scheme are discussed. An experimental setup is described, which was realised to study the behaviour of the ranging principle under real-world conditions. The results of laboratory and flight tests are presented and evaluated.
In sidetone ranging, the distance between the sensor and a target is determined by measuring the phases shift of sinus-oidal signals (sidetones) modulating a continuous laser beam, after having been reflected by a remote surface. Range measurements with a very high resolution can readily be realised this way at high measurement rates. Multiple frequen-cies are used to provide a large unambiguous range.
Due to the high resolution and accuracy potential, of this ranging method, it seemed a promising idea to implement it into an airborne sensor for 3-D terrain survey. A highly collimated monoscopic ranging beam combined with the high sampling rates and the high range resolutions allow 3-D surface mapping in great detail. Additionally, surface reflectance can easily be derived from the sidetone amplitudes in the return signal, which are independent of foreign illumination.
An experimental scanning laser altimeter setup suitable for airborne tests was realised. Its key components are a laser diode, which is amplitude modulated by two sidetone frequencies, and a rotating mirror which deflects the ranging beam conically at 10 Hz. Range and reflectance are sampled at 7.5 kHz. At an altitude of 500 m above ground, the surface is sampled within a swath of 170 m with a sample point diameter of 0.5 m, and distances between neighbouring samples are 0.8 m across the direction of flight and at most 6 m along track. The maximum range was found to be 570 m with a range resolution between 0.03 m and 0.17 m . These values correspond well to values predicted by model calcu-lations.
The characteristic behaviour of the ranging scheme under real-world conditions was studied by comparing the data col-lected by the laser altimeter during a test flight, with a reference digital elevation model (DEM) generated from stcreophotogrammetrically evaluated aerial photos. The mean altitude difference between both data sets is 0.23 m with a standard deviation of 0.5 m. Significant altitude differences can only be observed at the edges of buildings and above vegetation. A detailed analysis reveals that the majority of deviations results from shadows in the aerial photos, causing no-data areas in the reference DEM. and occasional sensor misbehaviour at surface discontinuities.
The multi-frequency sidetone ranging scheme performed especially well in detecting continuous surface modulation with high accuracy. Also, the shapes and sizes of natural and artificial surface objects were captured precisely. Surprisingly, even in forested areas, ground and canopy points were discriminated well. The tests, however, also showed, that ranging to water surfaces is not possible. The combination of reflectance and elevation data turned out be useful to automatically distinguish between artificial and natural surface objects (e.g. houses and trees).
In conclusion, multi-frequency sidetone ranging can be considered well suited as a powerful ranging scheme for high-resolution scanning laser altimeters. It was successfully implemented in a functional sensor which, although experimen-tal, already proved competitive with commercial laser rangers of the same class, which operate on the pulse-time-of-flight ranging principle. In addition, the realised scanning laser altimeter co-registers surface reflectance simultaneously to range, which opens the field for new methods of automatic surface object classification.Numéro de notice : 28022 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Thèse étrangère Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=63369 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 28022-01 35.10 Livre Centre de documentation En réserve M-103 Disponible 28022-02 35.10 Livre Centre de documentation En réserve M-103 Disponible Entwicklung eines Meßsystems zur Ermittlung von Turbulenzparametern der Atmosphäre für Anwendungen in der Geodäsie / Maria Hennes (1995)
Titre : Entwicklung eines Meßsystems zur Ermittlung von Turbulenzparametern der Atmosphäre für Anwendungen in der Geodäsie Titre original : [Conception d'un système de mesures pour enquêter sur les paramètres de perturbation de l'atmosphère pour un usage en géodésie] Type de document : Thèse/HDR Auteurs : Maria Hennes, Auteur Editeur : Munich : Bayerische Akademie der Wissenschaften Année de publication : 1995 Collection : DGK - C Sous-collection : Dissertationen num. 438 Importance : 133 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-7696-9481-9 Note générale : Bibliographie Langues : Allemand (ger) Descripteur : [Vedettes matières IGN] Géodésie
[Termes IGN] étalonnage d'instrument
[Termes IGN] mécomètre
[Termes IGN] propagation du signal
[Termes IGN] réfraction atmosphérique
[Termes IGN] signal laser
[Termes IGN] télémètre laser
[Termes IGN] thermomètreIndex. décimale : 30.03 Instruments de géodésie Résumé : (Auteur) With the development of distance measuring techniques in the last decades the problem of laser beam propagation through the atmosphere has gained importance. Small changes in the refractive index caused by turbulent motions in the atmosphere are primarily related to small temperature variations. These cause random phase distortions of the optical wave as well as intensity fluctuations (scintillations), from which parameters describing the turbulence, e.g. the structure constant and the inner scale length, can be derived. Using the dissipation technique a relationship between these quantities and the vertical refraction index gradient has been formulated.
The major topic is the development of a measuring system based on a surveying instrument, which is capable of providing fluctuation quantities simultaneously with the "geodetic" observation itself. With regard to the distance measurement the high-precision distancemeter Kern Mekometer ME 5000 (LEICA, Heerbrugg, Switzerland) was chosen and modified in a way that distance-(phase-) and intensity-fluctuations can be acquired simultaneously with a sufficient high data rate by analyzing the received light intensity signal (= photodetector output). The necessary transformation equations are developed by analyzing both the optical ray path and the electrical signal path in the instrument. Resolution and absolute accuracy of the instrument are improved by a special calibration routine and an optimization process. Distance variations can be measured with an accuracy of 20 jam and the resolution of intensity fluctuations is 0.6 percent.
The extended semi-empirical modelling of refraction effects based on fluctuation data will be improved and controlled by additional information, e.g. the vertical gradient of the refraction index, wind speed and (local) structure constants. Therefore the measuring system is expanded by some other compo--nents: A scintillometer provides the integral vertical refraction index gradient and a modified sonic anemometer/thermometer provides the wind velocity as well as the local structure constant of the temperature. Selected and calibrated analog temperature sensors are incorporated to measure local temperature gradients. Most of these instruments are connected with a common data acquisition unit, which is developed with respect to the requirements of different correlation processes. The combination of all these modules represents a system for determining turbulence effects on distance and angle measurements and should be suited for improving refraction models.Numéro de notice : 28051 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse étrangère Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=63398 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 28051-01 30.03 Livre Centre de documentation En réserve M-103 Disponible 28051-02 30.03 Livre Centre de documentation En réserve M-103 Disponible Journées de recherche 1995 LOEMI / Laboratoire d'opto-electronique et de micro-informatique (1985 - 2016) (1995)
Titre : Journées de recherche 1995 LOEMI Type de document : Actes de congrès Auteurs : Laboratoire d'opto-electronique et de micro-informatique (1985 - 2016), Auteur Editeur : Paris : Institut Géographique National - IGN (1940-2007) Année de publication : 1995 Conférence : Journées Recherche de l'IGN 1995 20/03/1990 21/03/1990 Saint-Mandé France Importance : 12 p. Format : 21 x 30 cm Note générale : Bibliographie Langues : Français (fre) Descripteur : [Vedettes matières IGN] Optique
[Termes IGN] astronomie
[Termes IGN] capteur aérien
[Termes IGN] chambre métrique
[Termes IGN] Laboratoire d'Optoélectronique et de Micro-informatique = Laboratoire d'Opto-électronique, de Métrologie et d'Instrumentation
[Termes IGN] télémètre laser aéroportéNuméro de notice : 53797 Affiliation des auteurs : IGN (1940-2011) Thématique : IMAGERIE Nature : Actes Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=35603 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 53797-01 CG.95 Livre Centre de documentation Congrès Disponible Earth oriented space research at Delft University of technology / B.A. Ambrosius (1994)
Titre : Earth oriented space research at Delft University of technology : 1990-1993 Type de document : Rapport Auteurs : B.A. Ambrosius, Éditeur scientifique ; R.H.N. Haagmans, Éditeur scientifique ; E. Vermaat, Éditeur scientifique Editeur : Delft : Delft University Press Année de publication : 1994 Importance : 136 p. Format : 16 x 24 cm ISBN/ISSN/EAN : 978-90-407-1021-6 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] altimétrie satellitaire par radar
[Termes IGN] champ de pesanteur terrestre
[Termes IGN] courant marin
[Termes IGN] croute terrestre
[Termes IGN] orbitographie
[Termes IGN] positionnement par GPS
[Termes IGN] positionnement par PRARE
[Termes IGN] Precise Range and Range Rate Equipment
[Termes IGN] rotation de la Terre
[Termes IGN] trajectographie par GPSIndex. décimale : 30.60 Géodésie spatiale Numéro de notice : 62406 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Rapport Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=44304 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 62406-02 30.60 Livre Centre de documentation Géodésie Disponible 62406-01 30.60 Livre Centre de documentation Géodésie Disponible 62406-03 30.60 Livre Centre de documentation Géodésie Disponible Proceedings of the first international airborne remote sensing, 1. Tome 1 / Environmental research institute of Michigan (1994)
Titre de série : Proceedings of the first international airborne remote sensing, 1 Titre : Tome 1 Type de document : Actes de congrès Auteurs : Environmental research institute of Michigan, Auteur Editeur : Ann Arbor (Michigan) : Environmental Research Institute of Michigan ERIM Année de publication : 1994 Conférence : ERIM 1994, 1st international airborne remote sensing 12/09/1994 15/09/1994 Strasbourg France Importance : 781 p. Format : 21 x 30 cm Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Télédétection
[Termes IGN] atmosphère terrestre
[Termes IGN] capteur (télédétection)
[Termes IGN] carte thématique
[Termes IGN] détecteur
[Termes IGN] détecteur à transfert de charge
[Termes IGN] données lidar
[Termes IGN] écologie
[Termes IGN] géologie
[Termes IGN] image optique
[Termes IGN] image radar
[Termes IGN] Lidar
[Termes IGN] milieu rural
[Termes IGN] milieu urbain
[Termes IGN] plateforme
[Termes IGN] pollution des eaux
[Termes IGN] radar
[Termes IGN] télédétection aérienne
[Termes IGN] véhicule aérienNuméro de notice : 66058A Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Actes Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=36927 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 66058-01A CG.94 Livre Centre de documentation Congrès Disponible Proceedings of the first international airborne remote sensing, 2. Tome 2 / Environmental research institute of Michigan (1994)PermalinkProceedings of the first international airborne remote sensing, 3. Tome 3 / Environmental research institute of Michigan (1994)PermalinkPermalinkLe positionnement extrême / Société des électriciens et des électroniciens (1992)PermalinkProceedings of the symposium refraction of transatmospheric signals in geodesy / J.C. DE Munck (1992)PermalinkL'atmosphère moyenne et les observations spatiales, école d'été internationale de physique spatiale, Marseille, août 1990 / Centre national d'études spatiales (1991)PermalinkEin relativistisches Modell für PRARE-Beobachtungen / M. Schmidt (1990)PermalinkRemote sensing and satellite navigation : complementary tools of space technology / P. Hartl in Photogrammetric record, vol 13 n° 74 (October 1989 - March 1990)Permalink6e colloque international sur l'instrumentation de la Télémétrie laser = Sixth International Workshop on laser ranging instrumentation organized jointly by CRGS, CERGA and IAG Special Study Group 2.51, 1. Volume 1 / Jean Gaignebet (1986)Permalink6e colloque international sur l'instrumentation de la Télémétrie laser = Sixth International Workshop on laser ranging instrumentation organized jointly by CRGS, CERGA and IAG Special Study Group 2.51, 2. Volume 2 / Jean Gaignebet (1986)PermalinkPRARE microwave tracking system: overview and present state of development / H. Wilmes (04/11/1985)PermalinkThe use of artificial satellites for geodesy and geodynamics, Proceedings of the second international symposium on the use of artificial satellites for geodesy and geodynamics, Athens, May 29 - June 2, 1978 / G. Veis (1979)PermalinkProgress report 1978 of the Zimmerwald satellite observation station / P. Kloeckler (1978)PermalinkThe DFVLR LIDAR system 5 / Christian Werner (1976)PermalinkThe use of artificial satellites for geodesy and geodynamics, Proceedings of the International Symposium on the use of artificial satellites for Geodesy and Geodynamics, Athens, May 14-21, 1973 / G. Veis (1974)PermalinkLa télémétrie Laser, participation de l'ONERA aux opérations de géodésie au moyen des satellites "Diadème" / R. Moreau (1969)Permalink