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Galileo and QZSS precise orbit and clock determination using new satellite metadata / Xingxing Li in Journal of geodesy, vol 93 n° 8 (August 2019)
Titre : Galileo and QZSS precise orbit and clock determination using new satellite metadata Type de document : Article/Communication Auteurs : Xingxing Li, Auteur ; Yongqiang Yuan, Auteur ; Jiande Huang, Auteur ; et al., Auteur Année de publication : 2019 Article en page(s) : pp 1123 - 1136 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes descripteurs IGN] Capacité opérationnelle totale
[Termes descripteurs IGN] centre de phase
[Termes descripteurs IGN] constellation Galileo
[Termes descripteurs IGN] données satellitaires
[Termes descripteurs IGN] GIOVE (satellite)
[Termes descripteurs IGN] horloge du satellite
[Termes descripteurs IGN] lacet
[Termes descripteurs IGN] métadonnées
[Termes descripteurs IGN] modèle d'orbite
[Termes descripteurs IGN] orbite précise
[Termes descripteurs IGN] orbitographie
[Termes descripteurs IGN] Quasi-Zenith Satellite System
[Termes descripteurs IGN] rayonnement solaire
[Termes descripteurs IGN] variance d'AllanRésumé : (auteur) During 2016–2018, satellite metadata/information including antenna parameters, attitude laws and physical characteristics such as mass, dimensions and optical properties were released for Galileo and QZSS (except for the QZS-1 optical coefficients). These metadata are critical for improving the accuracy of precise orbit and clock determination. In this contribution, we evaluate the benefits of these new metadata to orbit and clock in three aspects: the phase center offsets and variations (PCO and PCV), the yaw-attitude model and solar radiation pressure (SRP) model. The updating of Galileo PCO and PCV corrections, from the values estimated by Deutsches Zentrum für Luft- und Raumfahrt and Deutsches GeoForschungsZentrum to the chamber calibrations disclosed by new metadata, has only a slight influence on Galileo orbits, with overlap differences within only 1 mm. By modeling the yaw attitude of Galileo satellites and QZS-2 spacecraft (SVN J002) according to new published attitude laws, the residuals of ionosphere-free carrier-phase combinations can be obviously decreased in yaw maneuver seasons. With the new attitude models, the 3D overlap RMS in eclipse seasons can be decreased from 12.3 cm, 14.7 cm, 16.8 cm and 34.7 cm to 11.7 cm, 13.4 cm, 15.8 cm and 32.9 cm for Galileo In-Orbit Validation (IOV), Full Operational Capability (FOC), FOC in elliptical orbits (FOCe) and QZS-2 satellites, respectively. By applying the a priori box-wing SRP model with new satellite dimensions and optical coefficients, the 3D overlap RMS are 5.3 cm, 6.2 cm, 5.3 cm and 16.6 cm for Galileo IOV, FOCe, FOC and QZS-2 satellites, with improvements of 11.0%, 14.7%, 14.0% and 13.8% when compared with the updated Extended CODE Orbit Model (ECOM2). The satellite laser ranging (SLR) validation reveals that the a priori box-wing model has smaller mean biases of − 0.4 cm, − 0.4 cm and 0.6 cm for Galileo FOCe, FOC and QZS-2 satellites, while a slightly larger mean bias of − 1.0 cm is observed for Galileo IOV satellites. Moreover, the SLR residual dependencies of Galileo IOV and FOC satellites on the elongation angle almost vanish when the a priori box-wing SRP model is applied. As for satellite clocks, a visible bump appears in the Modified Allan deviation at integration time of 20,000 s for Galileo Passive Hydrogen Maser with ECOM2, while it almost vanishes when the a priori box-wing SRP model and new metadata are applied. The standard deviations of clock overlap can also be significantly reduced by using new metadata. Numéro de notice : A2019-383 Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-019-01230-4 date de publication en ligne : 02/02/2019 En ligne : https://doi.org/10.1007/s00190-019-01230-4 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=93462
in Journal of geodesy > vol 93 n° 8 (August 2019) . - pp 1123 - 1136[article]
Titre : Concept of AHRS algorithm designed for platform independent IMU attitude alignment Type de document : Article/Communication Auteurs : Dariusz Tomaszewski, Auteur ; Jacek Rapinski, Auteur ; Renata Pelc-Mieczkowska, Auteur Année de publication : 2017 Article en page(s) : pp 33 - 47 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement
[Termes descripteurs IGN] accélération
[Termes descripteurs IGN] angle d'Euler
[Termes descripteurs IGN] attitude and heading reference system AHRS
[Termes descripteurs IGN] centrale inertielle
[Termes descripteurs IGN] instabilité du vecteur (télédétection)
[Termes descripteurs IGN] système de coordonnées
[Termes descripteurs IGN] téléphone intelligentRésumé : (Auteur) Nowadays, along with the advancement of technology one can notice the rapid development of various types of navigation systems. So far the most popular satellite navigation, is now supported by positioning results calculated with use of other measurement system. The method and manner of integration will depend directly on the destination of system being developed. To increase the frequency of readings and improve the operation of outdoor navigation systems, one will support satellite navigation systems (GPS, GLONASS ect.) with inertial navigation. Such method of navigation consists of several steps. The first stage is the determination of initial orientation of inertial measurement unit, called INS alignment. During this process, on the basis of acceleration and the angular velocity readings, values of Euler angles (pitch, roll, yaw) are calculated allowing for unambiguous orientation of the sensor coordinate system relative to external coordinate system. The following study presents the concept of AHRS (Attitude and heading reference system) algorithm, allowing to define the Euler angles. The study were conducted with the use of readings from low-cost MEMS cell phone sensors. Subsequently the results of the study were analyzed to determine the accuracy of featured algorithm. On the basis of performed experiments the legitimacy of developed algorithm was stated. Numéro de notice : A2017-794 Thématique : POSITIONNEMENT Nature : Article DOI : 10.1515/rgg-2017-0013 En ligne : https://doi.org/10.1515/rgg-2017-0013 Format de la ressource électronique : URL Article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=89071
in Reports on geodesy and geoinformatics > vol 104 n° 1 (December 2017) . - pp 33 - 47[article]
Titre : Correction of ZY-3 image distortion caused by satellite jitter via virtual steady reimaging using attitude data Type de document : Article/Communication Auteurs : Mi Wang, Auteur ; Ying Zhu, Auteur ; Shuying Jin, Auteur ; et al., Auteur Année de publication : 2016 Article en page(s) : pp 108 - 123 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s)
[Termes descripteurs IGN] distorsion d'image
[Termes descripteurs IGN] image satellite
[Termes descripteurs IGN] image ZiYuan-3
[Termes descripteurs IGN] instabilité du vecteur (télédétection)
[Termes descripteurs IGN] interpolation
[Termes descripteurs IGN] modèle de déformation des images
[Termes descripteurs IGN] modèle par fonctions rationnellesRésumé : (Auteur) ZiYuan-3 (ZY-3), the first Chinese civilian stereo mapping satellite, suffers from 0.67 Hz satellite jitter that deteriorates its geometric performance in mapping, resource monitoring and other applications. This paper proposes a distortion correction method based on virtual steady reimaging (VSRI) using attitude data to eliminate the negative influence caused by satellite jitter in satellite data preprocessing. VSRI helps linear array pushbroom cameras rescan the ground with a uniform integral time and smooth attitude. In this method, a VSRI model is proposed, and the geometric relationship between the original and corrected image is determined in terms of geolocation consistency based on a rigorous geometric model. Thus, the corrected image is obtained by resampling from the original one. Three areas of ZY-3 three-line images suffering from satellite jitter were used to validate the accuracy and efficiency of the proposed method. First, different attitude interpolation methods were compared. It is found that the Lagrange polynomial model and the cubic piecewise polynomial model have higher interpolation accuracy for original imagery. Then, the replacement accuracy of the rational function model (RFM) for ZY-3 was analyzed with 0.67 Hz satellite jitter. The results indicate that attitude oscillation reduces the fitting precision of the RFM for the rigorous imaging model. Finally, the relative orientation accuracy of the three-line images and the geo-positioning accuracy with ground control points (GCPs) before and after distortion correction were compared. The results show that the distortion caused by satellite jitter is corrected efficiently, and the accuracy of the three experimental datasets is improved in both the image space and the ground space. Numéro de notice : A2016-780 Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern En ligne : http://dx.doi.org/10.1016/j.isprsjprs.2016.05.012 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=82475
in ISPRS Journal of photogrammetry and remote sensing > vol 119 (September 2016) . - pp 108 - 123[article]
Titre : Estimating the yaw-attitude of an BDS IGSO and MEO satellites Type de document : Article/Communication Auteurs : Xiaolei Dai, Auteur ; Maorong Ge, Auteur ; Yidong Lou, Auteur ; et al., Auteur Année de publication : 2015 Article en page(s) : pp 1005-1018 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Techniques orbitales
[Termes descripteurs IGN] constellation BeiDou
[Termes descripteurs IGN] instabilité du vecteur (télédétection)
[Termes descripteurs IGN] lacet
[Termes descripteurs IGN] orbitographie
[Termes descripteurs IGN] orientation du capteur
[Termes descripteurs IGN] positionnement par BeiDou
[Termes descripteurs IGN] positionnement ponctuel précisRésumé : (auteur) Precise knowledge and consistent modeling of the yaw-attitude of GNSS satellites are essential for high-precision data processing and applications. As the exact attitude control mechanism for the satellites of the BeiDou Satellite Navigation System (BDS) is not yet released, the reverse kinematic precise point positioning (PPP) method was applied in our study. However, we confirm that the recent precise orbit determination (POD) processing for GPS satellites could not provide suitable products for estimating BDS attitude using the reverse PPP because of the special attitude control switching between the nominal and the orbit-normal mode. In our study, we propose a modified processing schema for studying the attitude behavior of the BDS satellites. In this approach, the observations of the satellites during and after attitude switch are excluded in the POD processing, so that the estimates, which are needed in the reverse PPP, are not contaminated by the inaccurate initial attitude mode. The modified process is validated by experimental data sets and the attitude yaw-angles of the BDS IGSO and MEO satellites are estimated with an accuracy of better than 9∘. Furthermore, the results confirm that the switch is executed when the Sun elevation is about 4∘ and the actual orientation is very close to its target one. Based on the estimated yaw-angles, a preliminary attitude switch model was established and reintroduced into the POD, yielding to a substantial improvement in the orbit overlap RMS. Numéro de notice : A2015-880 Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern En ligne : http://link.springer.com/article/10.1007/s00190-015-0829-x/fulltext.html Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=79412
in Journal of geodesy > vol 89 n° 10 (october 2015) . - pp 1005-1018[article]Algorithms for vision-based path following along previously taught paths / Deon George Sabatta (2015)
Titre : Algorithms for vision-based path following along previously taught paths Type de document : Thèse/HDR Auteurs : Deon George Sabatta, Auteur Editeur : Zurich : Eidgenossische Technische Hochschule ETH - Ecole Polytechnique Fédérale de Zurich EPFZ Année de publication : 2015 Collection : Dissertationen ETH num. 22391 Format : 21 x 30 cm Note générale : bibliographie
A thesis submitted to attain the degree of doctor of sciences of ETH ZurichLangues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géomatique
[Termes descripteurs IGN] base de données d'images
[Termes descripteurs IGN] calcul d'itinéraire
[Termes descripteurs IGN] chemin le plus court (algorithme)
[Termes descripteurs IGN] lacet
[Termes descripteurs IGN] milieu urbain
[Termes descripteurs IGN] navigation autonome
[Termes descripteurs IGN] optimisation (mathématiques)
[Termes descripteurs IGN] vision par ordinateurRésumé : (auteur) This thesis focusses on the task of navigating an autonomous vehicle along a previously driven path using feedback obtained from a camera system. The desired path is stored in the form of a “visual memory”, essentially a collection of images, captured when the vehicle was first driven along the path. Algorithms of this form find applications in many semi-autonomous inspection/exploration tasks, where the vehicle is initially navigated by an operator, using the visual data for other purposes. On completion of the task, the operator has provided the autonomous vehicle with all the information it needs to find its way back to the starting location, and potentially repeat the entire trip. By using reference images recorded along the initial path, the system is afforded a form of global localisation using only local sensing, by providing relative information to specific key-points within the environment.
The work presented in this thesis uses, as a base, two well established path following controllers, and extends these control algorithms into the visual domain, by deriving the required parameters of each of the controllers from information gathered in the images. One of the key focus points of this work is the use of only the bearing (yaw) information from the images. By only working with feature bearing information we essentially reduce the number of parameters by half (by ignoring elevation) without sacrificing performance on 2D-manifolds.
The first controller extends the well-known shortest distance to path control algorithm, by deriving a scaled distance to path and relative orientation from the visual memory. Using the scaled distance to path, we incorporate the unknown scale that typically plagues vision-based systems, into the controller to remove the velocity dependence of the control law. This algorithm was implemented and tested in an indoor environment with a motion capture system.
The second controller extends a model predictive control (MPC) based algorithm, derived during the 2007 DARPA Grand Challenge and initially reliant on GPS information, to make use of image data, thereby alleviating the need for GPS position information. To achieve this, a novel image-based cost function is proposed that can relate the relative distances between several images. This cost function guides the choice of control trajectories to minimise the computed cost from the reference path. The performance of the proposed cost function is examined in detail, including the effects of the number of features, average distance to feature, feature observation noise and the number of outliers.
To use this cost function, the control algorithm also needs an indication of how future actions will affect the cost, and to this end feature extrapolation becomes necessary. With limited visual information, and short baselines, this process is often not very successful, and various techniques are presented to improve the performance. These include the weighting of features based on their error prediction, and the reduction of the prediction horizon required by the controller.
This control algorithm was demonstrated in both urban and extra-urban settings over paths on the order of 400m where the performance is shown to be comparable to that of differential GPS. Finally, it is also shown how the algorithm can be simply adapted to incorporate collision avoidance behaviour during the path replay in the event that the environment has changed between recording and playback.Numéro de notice : 17201 Thématique : GEOMATIQUE/IMAGERIE Nature : Thèse étrangère Note de thèse : Doctoral thesis : Sciences : ETH Zurich : 2015 En ligne : http://dx.doi.org/10.3929/ethz-a-010419338 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81177 Etude bibliographique pour la mise en place d'une chaine d'acquisition multicapteurs très haute résolution sur un vecteur volant à basse altitude / Antoine Gademer (2006)
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