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Auteur T. Ohlhof |
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Lokale, regionale und globale Punktbestimmung mit Dreizeilenbilddaten und Bahninformation der Mars 96-Mission / T. Ohlhof (1996)
Titre : Lokale, regionale und globale Punktbestimmung mit Dreizeilenbilddaten und Bahninformation der Mars 96-Mission Titre original : [Le positionnement local, régional et global de points avec des données 3D et l'information de trajectoire de la mission 1996 de Mars] Type de document : Thèse/HDR Auteurs : T. Ohlhof, Auteur Editeur : Munich : Bayerische Akademie der Wissenschaften Année de publication : 1996 Collection : DGK - C Sous-collection : Dissertationen num. 445 Importance : 136 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-7696-9488-8 Note générale : Bibliographie Langues : Allemand (ger) Descripteur : [Vedettes matières IGN] Photogrammétrie numérique
[Termes IGN] compensation par bloc
[Termes IGN] compensation par faisceaux
[Termes IGN] image numérique
[Termes IGN] Mars (planète)
[Termes IGN] mission spatiale
[Termes IGN] simulation
[Termes IGN] trajectoire (véhicule non spatial)Index. décimale : 33.30 Photogrammétrie numérique Résumé : (Auteur) For the forthcoming Mars96 mission a procedure for high precision point determination based on an extended, physically consistent bundle block adjustment has been developed and verified using simulated and practical data. The procedure serves to reconstruct the exterior orientation of the two stereo cameras HRSC (High Resolution Stereo Camera) and WAOSS (Wide-Angle Optoelectronic Stereo Scanner), to improve the existing Mars control network in accuracy and density, and to determine non-photogrammetric model parameters, e.g. the Mars rotation parameters, more accurately.
The Russian Mars96 spacecraft is scheduled for launch in October 1996. The German stereo cameras HRSC and WAOSS are some of the most important instruments of the spacecraft. They will be operated in a highly elliptic Mars orbit to image the planetary surface at local, regional and global scale. From the recorded imagery the terrain surface will be reconstructed 3-dimensionally by photogrammetric means.
The photogrammetric evaluation of the HRSC/WAOSS data starts with the precise reconstruction of the exterior orientation of the images and the determination of ground points on Mars within the scope of a bundle block adjustment. Besides image information represented by a large amount of conjugate points which are measured automatically, control information is required for point determination. Due to the lack of accurate ground control points and navigation systems like GPS or INS, orbit and attitude determination of the Mars96 spacecraft are of high importance.
The mathematical model of bundle block adjustment is based on the collinearity equations. Due to the dynamical mode of image acquisition, each image line has its own exterior orientation with 6 unknown orientation parameters. Since the existing image and control information is not sufficient to estimate all unknowns, the 6 orientation parameters are treated as unknowns only for so-called orientation points, which are introduced at certain time intervals, e.g. once for every 100th or 1000th readout cycle. In between, the orientation parameters of each image line are expressed as polynomials of the parameters of the neighbouring orientation points.
While this approach reduces the number of unknown orientation parameters to a reasonable amount, it has several disadvantages:
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Any physical relation between the exterior orientation at subsequent orientation points is neglected
entirely, since the positions are modeled by piecewise polynomials and not by orbital constraints.
The statistical properties of the position data derived from orbit determination are improperly considered in the bundle adjustment.
The positional exterior orientation parameters estimated in the bundle adjustment do not permit an interpretation in terms of physical parameters.
In order to avoid these disadvantages, a new appraoch has been developed, which guarantees that all exposure stations of the cameras are lying on a physically consistent trajectory. To this end, the position parameters, which have been estimated so far at arbitrary orientation points, are now replaced by the 6 parameters of the epoch state vector and additional orbit model parameters. In addition, epoch state vector and orbit model para-meters are introduced into the bundle adjustment as direct observations with their full covariance information. Statistically, the resulting estimation procedure is equivalent to a combined orbit determination and bundle adjustment from radio tracking data and 3-line image data.
Computer simulations on point determination have been performed to obtain a survey of the attainable accuracy at local, regional and global levels. Since WAOSS will image the entire planet, a closed block covering the entire Martian surface may be processed under ideal circumstances. Because of the extraordinary strength of the closed block and based on the complete image, orbit, attitude and ground control information, 70 m accuracy in X, Y and Z can be achieved. Moreover, the Mars rotation parameters can be improved by factor 2-4. It can be stated that the synergy effect of image and orbit information is most effective, if many orbital arcs are processed simultaneously in a block of high geometric strength.
The new approach was tested also with practical data. Image data of the multi-line camera MOMS-02 and TDRSS tracking data, both acquired during the German D2 mission, were evaluated together. An empirical accuracy of 12m (0.9 pixel) in X, Y and Z was obtained with only 4 groups of ground control points. Thus the efficiency of the rigorous bundle adjustment approach integrating orbital constraints has been proved with practical data. For that reason, it will be routinely used for the MOMS-2P/PRIRODA mission to be launched in spring 1996.Numéro de notice : 28044 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Thèse étrangère Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=63391 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 28044-01 33.30 Livre Centre de documentation Photogrammétrie - Lasergrammétrie Disponible 28044-02 33.30 Livre Centre de documentation Photogrammétrie - Lasergrammétrie Disponible