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Development of a dispersometer for the implementation into geodetic high-accuracy direction measurement systems / Burkhard Böckem (2001)
Titre : Development of a dispersometer for the implementation into geodetic high-accuracy direction measurement systems Type de document : Thèse/HDR Auteurs : Burkhard Böckem, Auteur Editeur : Zurich : Institut für Geodäsie und Photogrammetrie IGP - ETH Année de publication : 2001 Collection : IGP Mitteilungen, ISSN 0252-9335 num. 73 Importance : 140 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-906467-33-7 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie
[Termes IGN] effet atmosphérique
[Termes IGN] émetteur
[Termes IGN] impulsion laser
[Termes IGN] mesurage électronique d'angles
[Termes IGN] mesurage électronique de distances
[Termes IGN] propagation du signal
[Termes IGN] rayonnement électromagnétique
[Termes IGN] récepteur bifréquence
[Termes IGN] réfraction atmosphérique
[Termes IGN] téléscopeIndex. décimale : 30.03 Instruments de géodésie Résumé : (Auteur) In the course of the progressive developments of sophisticated geodetic systems which offer a very high accuracy potential strategies for correcting atmosphere-related effects will become increasingly important. These atmosphere-related effects arise in a large span of time scales: systematic deviations caused by a quasi-stationary refractive index gradient environment, generally referred to as refraction in geodetic context, slowly transfer to stochastic deviations resulting from optical turbulence. Refraction corrected optical direction and angle measurements are required in numerous high-accuracy measurement applications. These applications include surveying tasks in connection with civil engineering projects, the alignment of particle accelerator facilities, surveying tasks in context within assembling processes in industrial environments, e.g. aircraft industry, tasks wherein surveying instruments provide the spatial guidance of large machines, etc. A dispersometer, based on the dual-wavelength method by utilizing atmospheric dispersion, constitutes a metrological solution to atmosphere-related effects. Another decisive advantage of a dispersometer is that the envisaged correction of atmosphere-related effects works integrally and is available in real time. The aim of this thesis was to develop this dispersometer to overcome atmospherically induced limitations in very high-accuracy direction and angle measurements. The dispersometer consists of two modules: the dual-wavelength transmitter and the detection system being composed of the dispersion telescope and a position sensitive detector. By applying the dual-wavelength method, the major .challenges in instrumental realization are the generation of coaxial single-mode emission at two spectrally optimized wavelengths and the achievement of optical position sensing accuracy in the order of a few nanometers. The development of the dispersometer is principally made possible by focussing on three key technologies: dual-wavelength generation by frequency conversion, optical fiber technology, and gap- technology. Within this work detailed studies of these three key technologies are performed. In this work it is demonstrated that a dual-wavelength laser by frequency conversion is clearly suited for the implementation in the dual-wavelength transmitter. Furthermore, a novel technique for achieving coaxial single-mode propagation at two spectrally wide-separated wavelengths by one single-mode fiber is established within this thesis. Due to the application of optical fiber technology it is now possible to couple both beams into one optical channel of a modem geodetic total station. In order to achieve optical position sensing with the accuracy of a few nanometers by using a short-focal-length receiving telescope, gap-technology by utilizing special segmented position sensitive detectors is applied. This thesis contains a complete treatment addressed to this technology. Within the course of dispersometer performance tests, difference position sensing accuracy of ó = 7.3 nm was achieved. Additionally, the existence of the position sensitive detector inherent dispersion was demonstrated. In combination with the dispersion of the receiving optics, the position sensitive detector inherent dispersion has to be considered for the measurement of the atmospheric dispersion induced displacement between both beams of different wavelengths. As a solution a self-calibration procedure which corrects the dispersion of the complete detection system is described. This self-calibration procedure which utilizes the impact of optical turbulence possesses the decisive advantages that it obviates the need of additional measurements and the dispersion correction can be computed and applied in real time. A substantial part of this thesis is devoted to dispersometer measurements. Two basic atmospheric conditions which are typical for industrial measurement tasks indoors were simulated. Additionally, a detailed study of the influence of the aperture diameter on the dispersometer measurements was performed. The optimal aperture diameter for the present instrumental layout and for the prevailing ambient conditions was 30 mm. For theodolite-like and smaller apertures it is confirmed that the accuracy of the refraction angle improves with the square root of the integration time. Due to dispersometer performance by using theodolite-like and possibly smaller apertures in combination with the self-calibration procedure, the implementation of a standard theodolite-telescope is proposed. In a moderately turbulent atmosphere the accuracy of the refraction angle for single- face telescope observation was found to be 0.2 µrad (0.01 mgon) after an integration time of 12 sand a sight length of 17 m. Summarizing the theoretical investigations, the key technologies involved in the instrumental development, and the experimental results, presented in this dissertation, it can be concluded that the realized dispersometer in combination with a theodolite is capable of the refraction corrected angular measurements, the influences of optical turbulence notwithstanding. The application of optical fiber technology and the envisaged implementation of a standard theodolite-telescope confirm the presumption that the realized dispersometer can be implemented into modem geodetic total stations. Improvements with respect to field-operativeness are expected by an industrial realization of the dispersometer and by implementing the dispersometer into modem geodetic total stations. The integration of blue laser diodes, when meeting the standards of nowadays infrared laser diodes, would significantly enhance efficiency and reduce overall costs. Due to the technologies presented within this thesis such an integration is clearly feasible. Numéro de notice : 14740 Affiliation des auteurs : non IGN Autre URL associée : http://dx.doi.org/10.3929/ethz-a-004176211 Thématique : POSITIONNEMENT Nature : Thèse étrangère DOI : 10.3929/ethz-a-004176211 En ligne : http://e-collection.library.ethz.ch/eserv/eth:24109/eth-24109-02.pdf Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=62684 Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 14740-01 30.03 Livre Centre de documentation En réserve M-103 Disponible Lasermessungen nach Erdsatelliten auf zwei Wellenlängen unter Verwendung einer Streak-Kamera / S. Riepl (1998)
Titre : Lasermessungen nach Erdsatelliten auf zwei Wellenlängen unter Verwendung einer Streak-Kamera Titre original : [Mesures laser sur satellites terrestres sur deux longueurs d'ondes en utilisant une caméra Streak] Type de document : Monographie Auteurs : S. Riepl, Auteur Editeur : Munich : Bayerische Akademie der Wissenschaften Année de publication : 1998 Collection : DGK - C Sous-collection : Dissertationen num. 495 Importance : 70 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-88648-056-2 Note générale : Bibliographie
Affil-ensgt :
Org-stage :Langues : Allemand (ger) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] impulsion laser
[Termes IGN] laser
[Termes IGN] propagation du signal
[Termes IGN] réfraction atmosphérique
[Termes IGN] scintillation
[Termes IGN] télémétrie laser sur satelliteIndex. décimale : 30.63 Télémétrie laser sur satellite, Télémétrie laser sur lune, VLBI Numéro de notice : 58066 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Monographie Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=60331 Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 58066-01 30.63 Livre Centre de documentation Géodésie 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 Exemplaires(2)
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 Satellitengeodätische Positionierung in der relativistischen Raum-Zeit / V. Schwarze (1995)
Titre : Satellitengeodätische Positionierung in der relativistischen Raum-Zeit Titre original : [Positionnement géodésique par satellites dans l'espace temps relatif] Type de document : Thèse/HDR Auteurs : V. Schwarze, Auteur Editeur : Munich : Bayerische Akademie der Wissenschaften Année de publication : 1995 Collection : DGK - C Sous-collection : Dissertationen num. 449 Importance : 125 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-7696-9492-5 Note générale : Bibliographie Langues : Allemand (ger) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] correction du signal
[Termes IGN] espace-temps
[Termes IGN] ligne géodésique
[Termes IGN] mesurage de phase
[Termes IGN] propagation du signal
[Termes IGN] signal GPS
[Termes IGN] théorie de la relativitéIndex. décimale : 30.61 Systèmes de Positionnement par Satellites du GNSS Résumé : (Auteur) Satellite based positioning in curved space-time
Within this thesis we reformulate the observation equations for all commonly applied satellite based positioning systems within the framework of general relativity. Let us start with the representation of the space-time metric with respect to a geocentric, Earth-fixed chart. The definition of geodetic observables on a curved space-time manifold follows. For this purpose one introduces the so called observation frames which can be tied to coordinate induced frames by the matrix of integrating factors. An explicit form of the matrix of integrating factors is given.
Since each measurement process consists of transmitting and receiving of electromagnetic signals which are influenced by the presence of the gravitational field and of a refractive-dispersive medium we reformulate the relation between signal travel time and the spatial coordinate distance. It can be shown that the equation of motion of an electromagnetic wave leads to the differential equation of a geodesic line.
On the basis of the improved physical model described above we have to derive observation equations leading to the well known form spatial coordinate distance plus additional model quantities for all commonly applied observation techniques like the time-difference technique, the phase-difference technique and the integrated Doppler-count. We investigate the quantitative influence of the relativistic model terms. Numerical calculations concerning the signal propagation in a refractive and disperive medium as well as the adjustment of a GPS data-set conclude this thesis.Numéro de notice : 28040 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse étrangère Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=63387 Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 28040-01 30.61 Livre Centre de documentation Géodésie Disponible Multipath and GPS / C. Bosloper (1990)
Titre : Multipath and GPS : short periodic components of the time variation of the differential dispersive delay Type de document : Monographie Auteurs : C. Bosloper, Auteur Editeur : Kensington [Australie] : University of New South Wales Année de publication : 1990 Collection : Unisurv Report num. S-39 Importance : 204 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-0-85839-057-7 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] GPS en mode différentiel
[Termes IGN] propagation du signal
[Termes IGN] signal GPS
[Termes IGN] trajet multipleIndex. décimale : 30.61 Systèmes de Positionnement par Satellites du GNSS Numéro de notice : 63990 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Monographie Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=61248 Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 63990-01 30.61 Livre Centre de documentation Géodésie Disponible Radarmétéorologie / H. Sauvageot (1982)PermalinkLa mesure des grandes longueurs, les stadimètres électroniques et leur emploi en topométrie / Michel Kasser (1980)PermalinkPrecise modelling aspects of lunar laser measurements and their use for the improvement of geodetic parameters / A. Stolz (1979)Permalink