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Reliability of direct georeferencing: An overview of the current approaches and possibilities / Jan Skaloud (2006)
Titre : Reliability of direct georeferencing: An overview of the current approaches and possibilities : Final report on phase 1 Type de document : Rapport Auteurs : Jan Skaloud, Auteur Editeur : Dublin : European Spatial Data Research EuroSDR Année de publication : 2006 Collection : EuroSDR official publication, ISSN 0257-0505 num. 51 Importance : pp 143 - 148 Format : 21 x 30 cm Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Photogrammétrie numérique
[Termes IGN] capteur spatial
[Termes IGN] centrale inertielle
[Termes IGN] contrôle qualité
[Termes IGN] données GNSS
[Termes IGN] étalonnage de capteur (imagerie)
[Termes IGN] filtre de Kalman
[Termes IGN] géoréférencement direct
[Termes IGN] GPS-INS
[Termes IGN] orientation du capteur intégrée
[Termes IGN] Receiver Autonomous Integrity MonitoringRésumé : (auteur) After some initial hesitations, the direct georeferencing (DG) of airborne sensors by GPS/INS is now a widely accepted approach in the airborne mapping industry. Implementing DG not only speeds up the mapping process and thus increases the productivity, but also opens the door to new monitoring applications. Although the system manufactures tend to claim that DG is a well established technique and no longer a research topic, the technology users often encounter pitfalls due to undetected sensor behavior, varying data quality and consistency. One could almost claim that the reliability of DG is the Achilles’ heel of this otherwise revolutionary approach in civil airborne mapping. EuroSDR has recognized this problem and would like to address it in several phases. First phase of this effort are some preliminary investigations, charting the current situation and making suggestions for further research. The investigations are divided into the following technology fields: GNSS, inertial sensors and estimation methods, integrity and communication, calibration and integrated sensor orientation. Each field describes the current situation with respect to DG and discusses additional existing possibilities. These do not claim to be complete or exhaustive; however, they claim to address the essential features, methods and processes, the combination of which could increase the reliability of DG substantially without setting large side penalties. Numéro de notice : H2006-002 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Chapître / contribution En ligne : http://www.eurosdr.net/publications/official-publication-no-51-2006 Format de la ressource électronique : URL bulletin Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=93668 Documents numériques
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Titre : The Swiss trolley : a modular system for track surveying Type de document : Rapport Auteurs : Ralph Glaus, Auteur Editeur : Zurich : Schweizerischen Geodatischen Kommission / Commission Géodésique Suisse Année de publication : 2006 Collection : Geodätisch-Geophysikalische Arbeiten in der Schweiz, ISSN 0257-1722 num. 70 Importance : 184 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-908440-13-0 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement
[Termes IGN] capteur imageur
[Termes IGN] capteur non-imageur
[Termes IGN] données localisées
[Termes IGN] filtre de Kalman
[Termes IGN] fonction spline
[Termes IGN] fusion de données
[Termes IGN] GPS en mode cinématique
[Termes IGN] GPS en mode différentiel
[Termes IGN] GPS-INS
[Termes IGN] lissage de données
[Termes IGN] navigation à l'estime
[Termes IGN] odomètre
[Termes IGN] positionnement absolu
[Termes IGN] précision millimétrique
[Termes IGN] prise de vue terrestre
[Termes IGN] réseau ferroviaire
[Termes IGN] surveillance d'ouvrage
[Termes IGN] tachéomètre électronique
[Termes IGN] transport ferroviaireIndex. décimale : 30.70 Navigation et positionnement Résumé : (Auteur) Modern railway infrastructure requires accurate, absolute referenced spatial data for project planning, construction and maintenance. On the one hand, passenger safety and travel comfort depend to a large extent on accurate tracks. On the other hand, absolute referenced coordinates of railway assets facilitate data exchange between railway operators and third parties. In addition, time slots for maintenance are short, due to the high volumes of traffic on major railway lines. Thus, flexible surveying systems are required yielding accurate data within a short time. The multi-sensor platform Swiss Trolley, which offers such a flexible system, copes with absolute referenced spatial data. The platform is mounted on a track vehicle. This allows for a complete description of the track environment in kinematic mode with a minimum of interference time with regular traffic.
The Swiss Trolley features a modular design. A basic module for assessing track key parameters such as chainage, cant, twist, gradients and track gauge covers monitoring tasks on construction sites. A positioning module integrating GPS or total stations allows for the determination of the track axis. A further scan module can be used to generate absolute referenced point clouds in the track environment.
This work compiles the development steps of the Swiss Trolley. Relevant side conditions re-garding track surveying, coming from track geometry and the railway operators are summarised and state-of-the-art systems are reviewed. Based on these premises, a niche for Swiss Trolley applications is defined. Sensors providing geometric data in the track environment are evaluated in regard to their suitability and error behaviour.
The key problem of the trolley positioning consists in determining the six degrees of freedom of the multi-sensor platform at any point in time. The chosen kinematic approach asks for a careful treatment of time constraints. Each data string coming from a specific sensor must own an accurate time tag. Kinematic surveys at walking speed with subcentimetric accuracy require time tags with millisecond accuracy.
The incorporated sensors were investigated regarding their error behaviour. Calibration issues are addressed and approaches for the bias determination are presented. Models for correcting collimation errors and nuisance accelearations are given for the pendulum inclination sensors used. Moreover, emphasis was placed on biases emerging at kinematic surveys for the particular optical total station used. Reduction models for the laser scanner data are proposed and calibration procedures providing intrinsic orientation and latency parameters are given.
A kinematic model for Swiss Trolley surveys based on the Frenet base system and its canonical representation was developed. Explicit formulae are given for runs on geometric elements dominating in the railway track environment. For the mutual data processing, a loosely coupled filter concept is proposed consisting of data pre-processing, synchronisation and filtering steps. The core of data processing is a Kalman filter, estimating vehicle and track states in an absolute or a relative reference frame. By means of the filter approach, the observations of the involved sensors can be integrated in a spatial model. Individual filter runs can be assembled by an additional merge step. Merged runs in up and down direction allow for a quality assessment and also allow for the monitoring of eventually remaining biases such as a boresight misalignment or inclination sensor zero point offsets.
Positioning accuracies for the static and kinematic case were assessed on the one hand by the comparison of up and down runs. On the other hand, comparisons were carried out with independently measured reference data. The static error behaviour of the Swiss Trolley could be evaluated by using a slab track alignment. Submillimetric positioning accuracies were obtained in combination with high-precision total stations. Kinematic positioning accuracy mainly depends on the positioning sensor used. Optical total stations providing synchronised angle and distance data allow for subcentimetric positioning. High-precision DGPS position-ing yields subcentimetric accuracy for the horizontal component. The typical vertical accuracy is better than two centimetres. The integrated longitudinally mounted inclination sensor slightly augments the mere GPS solution. The attitude determination of the platform is a result of the combined data treatment. For GPS surveys, the typical pitch angle accuracy is two mrad. Yaw angles essentially correspond to the derivation of the trajectory with respect to the covered path and are determined with one mrad accuracy. Roll angle accuracy is dominated by the inclination sensor measurements across the track. The typical accuracy is 0.3 mrad. For the scan module, laser dots in the absolute reference frame are degraded by the uncertainty of the trajectory and the platform attitude amplified by a geometry-depending lever. The absolute accuracy of such a dot is three centimetres using a time-of-flight laser scanner. Relative accuracy between two adjacent dots amounts to five millimetres.
The Swiss Trolley was successfully applied on numerous assignments. Adaptations for the multi-sensor platform exist for tunnel site locomotives and road-vehicles.Note de contenu : 1 Introduction
2 Track Geometry
2.1 Nominal Geometries
2.1.1 Introduction
2.1.2 Horizontal Layout
2.1.3 Vertical Layout
2.2 Rules and Standards of Different Countries
2.2.1 Horizontal Layout
2.2.2 Vertical Layout
2.2.3 Cant
2.3 Kinematic Model of Motion
2.3.1 Kinematics in the Frenet System
2.3.2 Canonical Representation of the Most Common Track Curves
2.4 Remarks on Track Accuracy
2.4.1 General Remarks
2.4.2 Relative and Absolute Accuracy of a Track
2.5 Methods for Track Surveying
2.5.1 Overview
2.5.2 Relative Track Surveying
2.5.3 Absolute Track Surveying
2.5.4 Selected Track-Surveying Systems
2.5.5 The Swiss Trolley - Finding the Niche
3 Potentials and Limitations of a Kinematic Track-Surveying System
3.1 Kinematic Surveying
3.2 Absolute Position Fixing
3.2.1 GNSS
3.2.2 Tracking Total Stations
3.3 Dead Reckoning
3.3.1 Inertial Navigation Systems (INS)
3.3.2 Yaw Rates by Chord Techniques
3.3.3 Odometers
3.3.4 Height Determination by an Inclination Sensor
3.4 Attitude Determination
3.5 Kinematic Surveys of the Railway Inventory
3.5.1 Track Gauge Measuring Systems
3.5.2 Laser Scanners
3.5.3 3D Cameras
3.5.4 Ground Penetration Radar (GPR)
3.6 Synchronisation
3.7 Modelling
3.8 Transformation
4 The Track-Surveying Trolley
4.1 Introduction
4.1.1 Development
4.1.2 Concept
4.2 Data Acquisition
4.2.1 Electronic Box
4.2.2 A/D Conversion
4.2.3 Data Synchronisation
4.3 Reconstruction
4.4 Inclination Sensors
4.4.1 Sensor Characteristics
4.4.2 Calibration of Characteristic Curve
4.4.3 Temperature Influences
4.4.4 Corrections for Non-Orthogonalities (Collimation Error)
4.4.5 Dynamic Behaviour of the Inclination Sensor
4.4.6 Transformation of the Inclination Angles into the Body-System
4.5 Track Gauge Measuring System
4.5.1 Characteristics and Measuring Principle of the Track Gauge Measuring System
4.5.2 Calibration
4.6 Odometers
4.6.1 Characteristics and Calibration
4.7 Integration of Tracking Total Stations
4.7.1 Characteristics
4.7.2 Common Total Station Biases
4.7.3 Deflections of the Vertical
4.7.4 Surveys in Canted Sections
4.7.5 Synchronisation of Distances and Angles
4.7.6 Internal Tacheometer and Radio Latencies
4.8 Integration of GPS
4.8.1 Characteristics
4.8.2 NMEA Data
4.9 Boresight Calibration of Prism and Antenna Phase Centre
4.10 Laser Scanners
4.10.1 Characteristics
4.10.2 Model
4.10.3 Yaw Angle Correction
4.10.4 Evaluation of the Laser Scanner Precision
4.10.5 Variance Propagation for a Given Scanner Arrangement
4.10.6 Kinematic Calibration of Rmb, xmb and the Latency
5 Data Processing
5.1 Introduction
5.2 Post-Processing Software Concept
5.3 Data Preprocessing
5.3.1 Blunder Labelling
5.3.2 Reduction, Model
5.3.3 Linear Filters
5.3.4 Synchronisation
5.3.5 Reduction to the Centre Line of the Track
5.4 Trajectory Smoothing by a Kalman Filter
5.4.1 Discrete Kalman Filter
5.4.2 Backward Filter and Smoother
5.4.3 Absolute Model
5.4.4 Relative Model
5.5 Smoothing Splines
5.5.1 Smoothing Splines with First Derivatives
5.5.2 Comparison between Kalman Filter and Smoothing Splines
5.6 Merging Trajectories
5.6.1 Strategies for Merging
5.6.2 Chaining the Pieces
5.6.3 Merging
5.6.4 Linking Scans to Merged Trajectories
6 Applications
6.1 Slab Track Alignment
6.2 Kinematic Track Axis Surveys
6.2.1 Comparison between Forward Filter, Backward Filter and Smoother
6.2.2 Filter Tuning
6.2.3 Comparison between Absolute and Relative Model
6.2.4 The Influence of Inclinometer Measurement on GPS Heights
6.2.5 The Smoother in Action - GPS Example
6.2.6 The Smoother in Action - Total Station Example
6.3 Kinematic Scanning
7 ConclusionsNuméro de notice : 15261 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Rapport de recherche En ligne : https://www.sgc.ethz.ch/sgc-volumes/sgk-70.pdf Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=55115 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 15261-01 30.70 Livre Centre de documentation Géodésie Disponible 15261-02 30.70 Livre Centre de documentation Géodésie Disponible A detail-preserving scale-driven approach to change detection in multitemporal SAR images / F. Bolovo in IEEE Transactions on geoscience and remote sensing, vol 43 n° 12 (December 2005)
[article]
Titre : A detail-preserving scale-driven approach to change detection in multitemporal SAR images Type de document : Article/Communication Auteurs : F. Bolovo, Auteur ; Lorenzo Bruzzone, Auteur Année de publication : 2005 Article en page(s) : pp 2963 - 2972 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image
[Termes IGN] détection de changement
[Termes IGN] filtre de déchatoiement
[Termes IGN] fusion d'images
[Termes IGN] image ERS-SAR
[Termes IGN] image multitemporelle
[Termes IGN] précision géométrique (imagerie)
[Termes IGN] transformation en ondelettesRésumé : (Auteur) This paper presents a novel approach to change detection in multitemporal synthetic aperture radar (SAR) images. The proposed approach exploits a wavelet-based multiscale decomposition of the log-ratio image (obtained by a comparison of the original multitemporal data) aimed at achieving different scales (levels) of representation of the change signal. Each scale is characterized by a different tradeoff between speckle reduction and preservation of geometrical details. For each pixel, a subset of reliable scales is identified on the basis of a local statistic measure applied to scale-dependent log-ratio images. The final change detection result is obtained according to an adaptive scale-driven fusion algorithm. Experimental results obtained on multitemporal SAR images acquired by the ERS-1 satellite confirm the effectiveness of the proposed approach. Numéro de notice : A2005-513 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2005.857987 En ligne : https://doi.org/10.1109/TGRS.2005.857987 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=27649
in IEEE Transactions on geoscience and remote sensing > vol 43 n° 12 (December 2005) . - pp 2963 - 2972[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 065-05121 RAB Revue Centre de documentation Revues en salle Disponible Accurate INS/DGPS positioning using INS data de-noising and autoregressive (AR) modeling of inertial sensor errors / S. Nassar in Geomatica, vol 59 n° 3 (September 2005)
[article]
Titre : Accurate INS/DGPS positioning using INS data de-noising and autoregressive (AR) modeling of inertial sensor errors Type de document : Article/Communication Auteurs : S. Nassar, Auteur Année de publication : 2005 Article en page(s) : pp 283 - 294 Note générale : Bibliographie Langues : Anglais (eng) Français (fre) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] centrale inertielle
[Termes IGN] correction du signal
[Termes IGN] étalonnage géométrique
[Termes IGN] filtrage du bruit
[Termes IGN] GPS en mode différentiel
[Termes IGN] GPS-INS
[Termes IGN] positionnement par GPSRésumé : (Auteur) Dans de nombreuses applications de navigation, le système intégré composé d'un système de navigation par inertie (SNI) et d'un système de positionnement global différentiel (SPGD) est devenu un outil standard. Dans ces systèmes, le SNI présente la position, la vitesse et l'orientation alors que le SPG fournit la vitesse et la position pour mettre à jour la solution du SNI et calibrer ses erreurs. Un des grands problèmes qui affectent l'exactitude du SNI-SPGD est l'existence de blocages fréquents des signaux du SPG. Durant ces périodes, le SNI présente la position et la vitesse comme un système autonome jusqu'à ce que les signaux du SPG redeviennent disponibles. Dans ce cas, les erreurs de position augmentent rapidement avec le temps en raison du comportement d'erreurs qui dépend du temps de la navigation autonome du SNI. Ces erreurs de position sont principalement régies par la qualité des mesures inertielles et le modèle d'erreurs du SNI mis en oeuvre. Par conséquent, le principal but de cet article est d'améliorer l'exactitude du positionnement durant les pannes du SPGD. Pour réaliser ce but, deux tâches sont accomplies, soit : améliorer la qualité des données inertielles et utiliser de meilleurs modèles d'erreurs du SNI. La première tâche sera obtenue en appliquant des techniques de dé-bruitage des ondelettes. Pour la deuxième tâche, des processus auto-régressifs seront utilisés. Ensuite, une combinaison des deux techniques proposées est mise en oeuvre. Pour tester le rendement du dé-bruitage des données du SNI et de la modélisation par processus auto-régressifs, deux jeux de données du SNI-SPGD sont utilisés. Les résultats montrent que l'algorithme proposé combinant le dé-bruitage des données du SNI et la modélisation auto-régressive des erreurs des capteurs du SNI ont amélioré l'exactitude du positionnement de plus de 40 % durant les périodes de panne du SPGD. Numéro de notice : A2005-455 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.5623/geomat-2005-0037 En ligne : https://doi.org/10.5623/geomat-2005-0037 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=27591
in Geomatica > vol 59 n° 3 (September 2005) . - pp 283 - 294[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 035-05031 RAB Revue Centre de documentation En réserve L003 Disponible Flexed for flight: tightly coupled integrated nav system adapts to data formats / J.F. Lorga in GPS world, vol 16 n° 6 (June 2005)
[article]
Titre : Flexed for flight: tightly coupled integrated nav system adapts to data formats Type de document : Article/Communication Auteurs : J.F. Lorga, Auteur ; et al., Auteur Année de publication : 2005 Article en page(s) : pp 27 - 34 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s)
[Termes IGN] drone
[Termes IGN] filtre de Kalman
[Termes IGN] GPS-INS
[Termes IGN] intégration de données
[Termes IGN] magnétomètre
[Termes IGN] positionnement par GNSS
[Termes IGN] programmation informatique
[Termes IGN] radar à antenne synthétiqueRésumé : (Auteur) The demanding requirements of a new miniaturized synthetic aperture radar (MiniSAR) system, adaptable to different types of data according to prevailing conditions, led these researchers to implement an extended Kalman filter that can process diverse combinations of GNSS observables using different types of positioning. The system shows promise for use in SAP motion compensation, photogrammetry, autonomous vehicle navigation, aerodynamic modeling, and other fields. Copyright Questex Media Group Inc Numéro de notice : A2005-585 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=27720
in GPS world > vol 16 n° 6 (June 2005) . - pp 27 - 34[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 067-05061 SL Revue Centre de documentation Revues en salle Disponible SPOT-4 Vegetation multi-temporal compositing for land cover change studies over tropical regions / João M.B. Carreiras in International Journal of Remote Sensing IJRS, vol 26 n° 7 (April 2005)PermalinkHierarchical recovery of digital terrain models from single and multiple return lidar data / Y. Hu in Photogrammetric Engineering & Remote Sensing, PERS, vol 71 n° 4 (April 2005)PermalinkOn improving navigation accuracy of GPS/INS systems / Dorota A. Grejner-Brzezinska in Photogrammetric Engineering & Remote Sensing, PERS, vol 71 n° 4 (April 2005)PermalinkEffects of thermosphere total density pertubations on LEO Orbits during severe geomagnetic conditions (Oct-Nov 2003) using Doris and SLR data / Florent Deleflie in Advances in space research, vol 36 n° 3 (March 2005)Permalink3D building facade reconstruction under mesh form from multiple wide angle views / Lionel Pénard (2005)PermalinkApports des techniques de filtrage non linéaire pour la navigation avec les systèmes de navigation inertiels et le GPS / A. Giremus (2005)PermalinkCodage, adaptation et comparaison d'agorithmes de squelettisation d'une surface sur le SIG LAMPS2 / Christophe Mangeat (2005)PermalinkDécomposition de signaux aléatoires stationnaires et non-stationnaires / Philippe Courmontagne (2005)PermalinkEin Beitrag zur Identifikation von dynamischen Strukturmodellen mit Methoden der adaptiven Kalman-Filterung / A. Eichhorn (2005)PermalinkPermalink