Global ETD Search

11	Adapting navigation and flight conventions to nextgen's en route operations Lee, Brian Moon 11 July 2011 (has links) In response to the unparalleled growth of demand for air traffic during the past few decades, the Federal Aviation Administration (FAA) launched the Next Generation Air Transportation (NextGen) program to restructure the National Airspace System (NAS). Among the research is the focus on direct, wind optimal routing using geodesic routes and flight operations that do not depend solely on ground based navigation aids (NAVAID) and a fixed airspace structure. While technologies, such as the Global Positioning System (GPS), exist to locate an aircraft at higher degrees of resolution with a larger coverage, the way in which this information is conveyed is long and cumbersome. Therefore, new ways to describe the airspace is desired. The thesis presents the results of an experimental investigation into three alternatives to fix/route and GPS methods. The first method is the Navigation Reference System (NRS) using an absolute grid based strategy that has been recently implemented in limited portions of the United States airspace. The second method, the Military Grid Reference System (MGRS), is also a grid based system, and it is used by NATO, but it has not been applied to the air traffic control context. The third alternative is Point Relation Navigation (PRN), which uses a single point of reference within each Air Route Traffic Center (ARTCC) airspace and acts as a hybrid of coordinate and radial fixes. 21 airline dispatchers from a single major U.S air carrier participated in an online assessment of the five methods above through specific tasks. Results indicate that most participants prefer the fix/route system over the others, followed closely by the PRN method. However, there were varying results across all of the methods in terms of speed and accuracy of completing the tasks. This study incites further interest in strategies to describe aircraft routes operating in a more flexible airspace. Navigation convention Aircraft navigation Point relation navigation PRN NRS GPS MGRS NextGen Global Positioning System Air traffic capacity Air traffic control
12	Two-Satellite Positioning with a Stable Frequency Reference, Altimeters, and Bistatic Satellite Altimetry Yen, Shih-Wei 05 July 2017 (has links) No description available. Electrical Engineering GPS GLONASS GNSS two-satellite positioning Rubidium oscillator barometric altimeter radar altimeter bistatic satellite altimetry aircraft navigation integrated navigation covariance analysis
13	Aircraft Based GPS Augmentation Using an On-Board RADAR Altimeter for Precision Approach and Landing of Unmanned Aircraft Systems Videmsek, Andrew R. 02 June 2020 (has links) No description available. Electrical Engineering Engineering Aircraft Landing Guidance Aircraft Navigation Global Navigation Satellite System GNSS Global Positioning System GPS Precision Approach and Landing RADAR Altimeter Aiding RALT Aiding Remotely Piloted Aircraft RPA Unmanned Aircraft Systems UAS
14	Obstacle Avoidance for Small Unmanned Air Vehicles Call, Brandon R. 20 September 2006 (has links) (PDF) Small UAVs are used for low altitude surveillance flights where unknown obstacles can be encountered. These UAVs can be given the capability to navigate in uncertain environments if obstacles are identified. This research presents an obstacle avoidance system for small UAVs. First, a mission waypoint path is created that avoids all known obstacles using a genetic algorithm. Then, while the UAV is in flight, obstacles are detected using a forward looking, onboard camera. Image features are found using the Harris Corner Detector and tracked through multiple video frames which provides three dimensional localization of the features. A sparse three dimensional map of features provides a rough estimate of obstacle locations. The features are grouped into potentially hazardous areas. The small UAV then employs a sliding mode control law on the autopilot to avoid obstacles. This research compares rapidly-exploring random trees to genetic algorithms for UAV pre-mission path planning. It also presents two methods for using image feature movement and UAV telemetry to calculate depth and detect obstacles. The first method uses pixel ray intersection and the second calculates depth from image feature movement. Obstacles are avoided with a success rate of 96%. computer vision optical flow feature tracking UAV robotics unmanned obstacle avoidance sense and avoid path planning aircraft navigation genetic algorithm rapidly-exploring random tree rrt flight simulator city maker aviones Electrical and Computer Engineering
15	Correction and Optimization of 4D aircraft trajectories by sharing wind and temperature information / Correction et Optimisation de trajectoires d'avions 4D par partage des informations de vent et de température Legrand, Karim 28 June 2019 (has links) Cette thèse s'inscrit dans l'amélioration de la gestion du trafic aérien. Le vent et la température sont deux paramètres omniprésents, subis, et à l'origine de nombreux biais de prédiction qui altèrent le suivi des trajectoires. Nous proposons une méthode pour limiter ces biais. Le concept "Wind and Température Networking" améliore la prédiction de trajectoire en utilisant le vent et la température mesurés par les avions voisins. Nous détaillons les effets de la température sur l'avion, permettant sa prise en compte. L'évaluation du concept est faite sur 8000 vols. Nous traitons du calcul de trajectoires optimales en présence de vent prédit, pour remplacer les actuelles routes de l'Atlantique Nord, et aboutir à des groupes de trajectoires optimisées et robustes. Dans la conclusion, nous présentons d'autres champs d'applications du partage de vents, et abordons les besoins en nouvelles infrastructures et protocoles de communication, nécessaires à la prise en compte de ce nouveau concept. / This thesis is related to air traffic management systems current changes. On the ground and in flight, trajectory calculation methods and available data differ. Wind and temperature are two ubiquitous parameters that are subject to and cause prediction bias. We propose a concept to limit this bias. Our "Wind and Temperature Networking" concept improves trajectory prediction, using wind and temperature information from neighboring aircraft. We detail the effects of temperature on the aircraft performances, allowing for temperature to be taken into account. The concept evaluation is done on 8000 flights. We discuss the calculation of optimal trajectories in the presence of predicted winds, to replace the current North Atlantic Tracks, and to provide optimized and robust groups of trajectories. The conclusion of this thesis presents other fields of wind sharing applications, and addresses the need for new telecommunications infrastructures and protocols. Partage d'informations de vent Partage d'informations de température Trajectoires d'avion Navigation aérienne Algorithmes de classification Estimation de vent Prédiction de vent Estimation de température Prédiction de température Partage de vents Partage de températures Calcul de trajectoires d’urgence Estimation de champs de vents Estimation de champs de température Wind networking Temperature networking Flight trajectories Aircraft robust optimal trajectory Trajectory prediction (aerospace Trajectory optimisation (aerospace) Aircraft navigation Clustering algorithms Wind estimation Wind prediction Temperature estimation Temperature prediction Wind information sharing Temperature information sharing Flight trajectories wind profiles Flight trajectories temperature profiles Driftdown calculations Wind field estimations Temperature field estimations 629

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