Improving the Accuracy of GNSS Receivers in Urban Canyons using an Upward-Facing Camera

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dc.contributor.advisorO'Keefe, Kyle P. G.
dc.contributor.authorGakne, Paul Verlaine
dc.contributor.committeememberGao, Yang
dc.contributor.committeememberWang, Ruisheng
dc.contributor.committeememberFapojuwo, Abraham Olatunji
dc.contributor.committeememberRuotsalainen, Laura
dc.date2018-11
dc.date.accessioned2018-07-05T20:17:13Z
dc.date.available2018-07-05T20:17:13Z
dc.date.issued2018-07-03
dc.description.abstractGlobal Navigation Satellite Systems are widely used as localization systems for various applications in indoor and outdoor environments. Autonomous vehicles for example rely on navigation sensors such as GNSS receivers, INS, odometers, LiDAR, radar, etc. However, none of these sensors alone is able to provide satisfactory position solutions in terms of accuracy, availability and reliability all the time and in all environments. This thesis presents a new tightly coupling method fusing the egomotion of a land vehicle estimated from a sky-pointing camera with GNSS signals and a digital map for navigation purposes in harsh urban canyon environments. The advantages of this configuration are three-fold: firstly, for the GNSS signals, the upward-facing camera will be used to classify the acquired images into sky and non-sky (known as segmentation). A satellite falling into the non-sky areas (e.g., buildings) will be rejected and not considered for the final position solution computation. Secondly, the narrow field of view sky-pointing camera is helpful for urban area egomotion estimation in the sense that it does not see most of the moving objects (e.g., cars) and thus is able to estimate the egomotion with fewer outliers than is typical with a forward-facing camera. Thirdly, the skyline can be extracted and serves as a finger print of the vehicle location in the city. This information can then be correlated with a 3D city model to obtain the vehicle location. In order to obtain an accurate solution from the proposed method, a few intermediate steps had to be taken into account. An improved image segmentation algorithm is presented. The output of this algorithm served for the skyline positioning and the camera-based multipath mitigation. Also, an accurate visual odometry was implemented. Moreover, the monocular-based visual odometry is able to determine the vehicle translation accurately but up to a scale only. An integrated system that tackles the scale factor issue is designed. From five datasets evaluated in this research, the proposed method has shown to be robust and provide more accurate position, velocity and attitude solution at least 83% of the time than the GNSS-only and loosely coupled GNSS/vision solutions.en_US
dc.identifier.citationGakne, P. V. (2018). Improving the Accuracy of GNSS Receivers in Urban Canyons using an Upward-Facing Camera (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/32274en_US
dc.identifier.doihttp://dx.doi.org/10.11575/PRISM/32274
dc.identifier.urihttp://hdl.handle.net/1880/107052
dc.language.isoeng
dc.publisher.facultyGraduate Studies
dc.publisher.facultySchulich School of Engineering
dc.publisher.institutionUniversity of Calgaryen
dc.publisher.placeCalgaryen
dc.rightsUniversity of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.
dc.subjectGPS
dc.subjectGNSS
dc.subjectSatellite
dc.subjectVisual Odometry
dc.subjectCamera
dc.subjectMotion estimation
dc.subjectTightly-coupling integration
dc.subjectVehicle navigation
dc.subjectImage Segmentation
dc.subject3D building model
dc.subjectUpward-facing camera
dc.subjectClustering algorithms
dc.subject.classificationStatisticsen_US
dc.subject.classificationEngineering--Aerospaceen_US
dc.subject.classificationEngineering--Automotiveen_US
dc.subject.classificationEngineering--Electronics and Electricalen_US
dc.subject.classificationRoboticsen_US
dc.titleImproving the Accuracy of GNSS Receivers in Urban Canyons using an Upward-Facing Camera
dc.typedoctoral thesis
thesis.degree.disciplineGeomatics Engineering
thesis.degree.grantorUniversity of Calgary
thesis.degree.nameDoctor of Philosophy (PhD)
ucalgary.item.requestcopytrue
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