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Full-Text Articles in Engineering
Precision Navigation Using Pre-Georegistered Map Data, Frederick C. Webber
Precision Navigation Using Pre-Georegistered Map Data, Frederick C. Webber
Theses and Dissertations
Navigation performance in small unmanned aerial vehicles (UAVs) is adversely affected by limitations in current sensor technology for small, lightweight sensors. Because most UAVs are equipped with cameras for mission-related purposes, it is advantageous to utilize the camera to improve the navigation solution. This research improves navigation by matching camera images to a priori georegistered image data and combining this update with existing image-aided navigation technology. The georegistration matching is done by projecting the images into the same plane, extracting features using the techniques Scale Invariant Feature Transform (SIFT) [5] and Speeded-Up Robust Features (SURF) [3]. The features are matched …
The Navigation Potential Of Ground Feature Tracking, Guner Mutlu
The Navigation Potential Of Ground Feature Tracking, Guner Mutlu
Theses and Dissertations
This research effort examines the reduction of error in inertial navigation aided by vision. This is part of an effort focused on navigation in a GPS denied environment. The navigation concept examined here consists of two main steps. First, extract the position of a tracked ground object using vision and geo-locate it in 3 dimensional navigation frame. In this first step multiple positions of the UAV are assumed known; think of a synthetic aperture. The only information about the tracked ground objects/features is the unit vector that points to the objects from the center of the camera. Two such vectors …
Uas Collision Avoidance Algorithm That Minimizes The Impact On Route Surveillance, Austin L. Smith
Uas Collision Avoidance Algorithm That Minimizes The Impact On Route Surveillance, Austin L. Smith
Theses and Dissertations
A collision avoidance algorithm is developed and implemented that is applicable to different types of unmanned aerial systems ranging from a single platform with the ability to perform all collision avoidance functions independently to multiple vehicles performing functions as a cooperative group with collision avoidance commands computed at a ground station. The collision avoidance system is exercised and tested using operational hardware and platforms and is demonstrated in representative missions similar to those planned for operational systems. The results presented are the first known flight tests of a global, three-dimensional, geometric collision avoidance system on an unmanned aircraft system. Novel …
Laser Dot Projection Photogrammetry And Force Balance Measurement Techniques For Flapping Wing Micro Air Vehicles, David H. Curtis
Laser Dot Projection Photogrammetry And Force Balance Measurement Techniques For Flapping Wing Micro Air Vehicles, David H. Curtis
Theses and Dissertations
The purpose of this research was to develop testing methods capable of analyzing the performance of a miniature flapping-wing mechanism that can later be adapted to a flapping wing micro air vehicle (MAV). A previously designed and built flapping only mechanism was used for testing, while a previously designed flapping and pitch mechanism was fabricated utilizing an Objet Eden 500V 3-dimensional printer and its operation demonstrated. The flapping mechanism was mounted on a six component force balance. Force and moment data were collected for a variety of wing sets at different flapping frequencies. The testing was conducted using wings composed …
Evaluation Of An Opnet Model For Unmanned Aerial Vehicle Networks, Clifton M. Durham
Evaluation Of An Opnet Model For Unmanned Aerial Vehicle Networks, Clifton M. Durham
Theses and Dissertations
The concept of Unmanned Aerial Vehicles (UAVs) was first used as early as the American Civil War, when the North and the South unsuccessfully attempted to launch balloons with explosive devices. Since the American Civil War, the UAV concept has been used in all subsequent military operations. Over the last few years, there has been an explosion in the use of UAVs in military operations, as well as civilian and commercial applications. UAV Mobile Ad Hoc Networks (MANETs) are fast becoming essential to conducting Network-Centric Warfare (NCW). As of October 2006, coalition UAVs, exclusive of hand-launched systems, had flown almost …
Surveillance Using Multiple Unmanned Aerial Vehicles, Christopher E. Booth
Surveillance Using Multiple Unmanned Aerial Vehicles, Christopher E. Booth
Theses and Dissertations
This study examines the performance and limitations of a heuristic cooperative control (CC) surveillance algorithm for multiple unmanned aerial vehicles (UAVs) under both simulation and demonstration. The algorithm generates Dubin's based paths and provides velocity feedback to accomplish simultaneous arrival onto a surveillance orbit around the target and maintains position while orbiting. The CC algorithm has two modes: one that generates commands to multiple UAVs for simultaneous arrival to a surveillance orbit, and one that maintains equal angular spacing about the orbit. In addition to positional performance metrics, percentage of target in-view time was also measured based on the UAV's …
Micro-Scale Flapping Wings For The Advancement Of Flying Mems, Nicholas R. Coleman
Micro-Scale Flapping Wings For The Advancement Of Flying Mems, Nicholas R. Coleman
Theses and Dissertations
This research effort presents conceptual micro scale air vehicles whose total dimensions are less than one millimeter. The initial effort was to advance the understanding of micro aerial vehicles at sub-millimeter dimensions by fabricating and testing micro scale flapping wings. Fabrication was accomplished using a surface micromachining process called PolyMUMPs™. Both rigid mechanical structures and biomimetic devices were designed and fabricated as part of this effort. The rigid mechanical structures focused on out of plane deflections with solid connections and assembling a multiple hinge wing structure through the aid of residual stress. These devices were actuated by double hot arm …