Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 21 of 21
Full-Text Articles in Engineering
Optimal Defense Of High Value Airborne Assets, Isaac E. Weintraub
Optimal Defense Of High Value Airborne Assets, Isaac E. Weintraub
Theses and Dissertations
Optimal control theory and differential game theory is applied to the study of the defense of high value airborne assets, particularly in the case of a single threat such as an adversarial aircraft or missile. Rather than utilizing onboard defenses of the high value airborne asset, defense is proposed using a teamed unmanned combat air vehicle. The common scenario throughout this dissertation involves the defense of a high value airborne asset (evader) teamed with an unmanned combat vehicle (defender) against a single threat (pursuer). The unmanned combat air vehicle (defender), provides defense in one of two ways: kinetic or directed …
Development Of A Drone-Mounted Wireless Attack Platform, Nathan V. Barker
Development Of A Drone-Mounted Wireless Attack Platform, Nathan V. Barker
Theses and Dissertations
The commercial drone market has grown rapidly due to the increasing utility and capabilities of drones. This new found popularity has made it possible for inexpensive drones capable of impressive carry capacities and flight times to reach the consumer market. These new features also offer an invaluable resource to wireless hackers. Capitalizing on their mobility, a wireless hacker can equip a drone with hacking tools to surpass physical security (e.g. fences) with relative ease and reach wireless networks. This research seeks to experimentally evaluate the ability of a drone-mounted wireless attack platform equipped with a directional antenna to conduct wireless …
Nonlinear Control Framework For Gimbal And Multirotor In Target Tracking, Jae Hun Lee
Nonlinear Control Framework For Gimbal And Multirotor In Target Tracking, Jae Hun Lee
Theses and Dissertations
This thesis presents some existing gimbal and UAV control algorithms as well as novel algorithms developed as the extensions of the existing ones. The existing image-based visual servoing algorithms for both gimbal and UAV require the depth information to the object of interest. The depth information is not measurable when only a monocular camera is used for tracking. This thesis is the result of contemplation to the question: how can the necessity for a depth measurement be removed? A novel gimbal algorithm using adaptive control is developed and presented with simulation and hardware results. Although the estimated depth using the …
A Compact Phased Array Radar For Uas Sense And Avoid, Jonathan Cullinan Spencer
A Compact Phased Array Radar For Uas Sense And Avoid, Jonathan Cullinan Spencer
Theses and Dissertations
As small unmanned aerial systems (UAS) are introduced into the national airspace, measures must be introduced to ensure that they do not interfere with manned aviation and other UAS. Radar provides an attractive solution because of its inherent range accuracy and because it works in diverse weather and lighting conditions. Traditional radar systems, however, are large and high power and do not meet the size, weight and power (SWaP) constraints imposed by UAS, and fully integrated automotive solution do not provide the necessary range. This thesis proposes a compact radar system that meets both the SWaP and range requirements for …
Design Of An All-In-One Embedded Flight Control System, Joel D. Elmore
Design Of An All-In-One Embedded Flight Control System, Joel D. Elmore
Theses and Dissertations
This thesis describes an all-in-one flight control system (FCS) that was designed for unmanned aerial vehicles (UAVs). The project focuses on the embedded hardware aspect of a stand-alone system with low-cost and reliability in mind.
Developments In Lfm-Cw Sar For Uav Operation, Craig Lee Stringham
Developments In Lfm-Cw Sar For Uav Operation, Craig Lee Stringham
Theses and Dissertations
Opportunities to use synthetic aperture radar (SAR) in scientific studies and military operations are expanding with the development of small SAR systems that can be operated on small unmanned air vehicles (UAV)s. While the nimble nature of small UAVs make them an attractive platform for many reasons, small UAVs are also more prone to deviate from a linear course due autopilot errors and external forces such as turbulence and wind. Thus, motion compensation and improved processing algorithms are required to properly focus the SAR images. The work of this dissertation overcomes some of the challenges and addresses some of the …
Cooperative Target Tracking Enhanced With The Sequence Memoizer, Everett A. Bryan
Cooperative Target Tracking Enhanced With The Sequence Memoizer, Everett A. Bryan
Theses and Dissertations
Target tracking is an important part of video surveillance from a UAV. Tracking a target in an urban environment can be difficult because of the number of occlusions present in the environment. If multiple UAVs are used to track a target and the target behavior is learned autonomously by the UAV then the task may become easier. This thesis explores the hypothesis that an existing cooperative control algorithm can be enhanced by a language modeling algorithm to improve over time the target tracking performance of one or more ground targets in a dense urban environment. Observations of target behavior are …
An Onboard Vision System For Unmanned Aerial Vehicle Guidance, Barrett Bruce Edwards
An Onboard Vision System For Unmanned Aerial Vehicle Guidance, Barrett Bruce Edwards
Theses and Dissertations
The viability of small Unmanned Aerial Vehicles (UAVs) as a stable platform for specific application use has been significantly advanced in recent years. Initial focus of lightweight UAV development was to create a craft capable of stable and controllable flight. This is largely a solved problem. Currently, the field has progressed to the point that unmanned aircraft can be carried in a backpack, launched by hand, weigh only a few pounds and be capable of navigating through unrestricted airspace. The most basic use of a UAV is to visually observe the environment and use that information to influence decision making. …
Low Cost/ High Precision Flight Dynamics Estimation Using The Square-Root Unscented Kalman Filter, Trevor H. Paulsen
Low Cost/ High Precision Flight Dynamics Estimation Using The Square-Root Unscented Kalman Filter, Trevor H. Paulsen
Theses and Dissertations
For over a decade, Brigham Young University's Microwave Earth Remote Sensing (MERS) team has been developing SAR systems and SAR processing algorithms. In order to create the most accurate image reconstruction algorithms, detailed aircraft motion data is essential. In 2008, the MERS team purchased a costly inertial measurement unit (IMU) coupled with a high precision global positioning system (GPS) from NovAtel, Inc. In order to lower the cost of obtaining detailed motion measurements, the MERS group decided to build a system that mimics the capability the NovAtel system as closely as possible for a much lower cost. As a first …
Construction Of Large Geo-Referenced Mosaics From Mav Video And Telemetry Data, Benjamin Kurt Heiner
Construction Of Large Geo-Referenced Mosaics From Mav Video And Telemetry Data, Benjamin Kurt Heiner
Theses and Dissertations
Miniature Aerial Vehicles (MAVs) are quickly gaining acceptance as a platform for performing remote sensing or surveillance of remote areas. However, because MAVs are typically flown close to the ground (1000 feet or less in altitude), their field of view for any one image is relatively small. In addition, the context of the video (where and at what orientation are the objects being observed, the relationship between images) is unclear from any one image. To overcome these problems, we propose a geo-referenced mosaicing method that creates a mosaic from the captured images and geo-references the mosaic using information from the …
Real-Time Wind Estimation And Video Compression Onboard Miniature Aerial Vehicles, Andres Felipe Rodriguez Perez
Real-Time Wind Estimation And Video Compression Onboard Miniature Aerial Vehicles, Andres Felipe Rodriguez Perez
Theses and Dissertations
Autonomous miniature air vehicles (MAVs) are becoming increasingly popular platforms for the collection of data about an area of interest for military and commercial applications. Two challenges that often present themselves in the process of collecting this data. First, winds can be a significant percentage of the MAV's airspeed and can affect the analysis of collected data if ignored. Second, the majority of MAV's video is transmitted using RF analog transmitters instead of the more desirable digital video due to the computational intensive compression requirements of digital video. This two-part thesis addresses these two challenges. First, this thesis presents an …
Decentralized Estimation Using Information Consensus Filters With A Multi-Static Uav Radar Tracking System, David W. Casbeer
Decentralized Estimation Using Information Consensus Filters With A Multi-Static Uav Radar Tracking System, David W. Casbeer
Theses and Dissertations
This dissertation lays out a multi-static radar system with mobile receivers. The transmitter is at a known location emitting a radar signal that bounces off a target. The echo is received by a team of UAVs that are capable of estimating both time-delay and Doppler from the received signal. Several methods for controlling the movement of mobile sensor platforms are presented to improve target tracking performance. Two optimization criteria are derived for the problem, both of which require some type of search procedure to find the desired solution. Simulations are used to show the benefit of using closed-loop sensor control …
A Surveillance System To Create And Distribute Geo-Referenced Mosaics Using Suav Video, Evan D. Andersen
A Surveillance System To Create And Distribute Geo-Referenced Mosaics Using Suav Video, Evan D. Andersen
Theses and Dissertations
Small Unmanned Aerial Vehicles (SUAVs) are an attractive choice for many surveillance tasks. However, video from an SUAV can be difficult to use in its raw form. In addition, the limitations inherent in the SUAV platform inhibit the distribution of video to remote users. To solve the problems with using SUAV video, we propose a system to automatically create geo-referenced mosiacs of video frames. We also present three novel techniques we have developed to improve ortho-rectification and geo-location accuracy of the mosaics. The most successful of these techniques is able to reduce geo-location error by a factor of 15 with …
Path Planning For Unmanned Air And Ground Vehicles In Urban Environments, Andrew B. Curtis
Path Planning For Unmanned Air And Ground Vehicles In Urban Environments, Andrew B. Curtis
Theses and Dissertations
Unmanned vehicle systems, specifically unmanned air vehicles (UAVs) and unmanned ground vehicles (UGVs), have become a popular research topic. This thesis discusses the potential of a UAV-UGV system used to track a human moving through complex urban terrain. This research focuses on path planning problems for both a UAV and a UGV, and presents effective solutions for both problems. In the UAV path planning problem, we desire to plan a path for a miniature fixed-wing UAV to fly through known urban terrain without colliding with any buildings. We present the Waypoint RRT (WRRT) algorithm, which accounts for UAV dynamics while …
Decentralized Control Of Multiple Uavs For Perimeter And Target Surveillance, Derek B. Kingston
Decentralized Control Of Multiple Uavs For Perimeter And Target Surveillance, Derek B. Kingston
Theses and Dissertations
With the recent development of reliable autonomous technologies for small unmanned air vehicles (UAVs), the algorithms utilizing teams of these vehicles are becoming an increasingly important research area. Unfortunately, there is no unified framework into which all (or even most) cooperative control problems fall. Five factors that affect the development of cooperative control algorithms are objective coupling, communication, completeness, robustness, and efficiency. We classify cooperative control algorithms by these factors and then present three algorithms with application to target and perimeter surveillance and a method for decentralized algorithm design. The primary contributions of this research are the development and analysis …
Transitions Between Hover And Level Flight For A Tailsitter Uav, Stephen R. Osborne
Transitions Between Hover And Level Flight For A Tailsitter Uav, Stephen R. Osborne
Theses and Dissertations
Vertical Take-Off and Land (VTOL) Unmanned Air Vehicles (UAVs) possess several desirable characteristics, such as being able to hover and take-off or land in confined areas. One type of VTOL airframe, the tailsitter, has all of these advantages, as well as being able to fly in the more energy-efficient level flight mode. The tailsitter can track trajectories that successfully transition between hover and level flight modes. Three methods for performing transitions are described: a simple controller, a feedback linearization controller, and an adaptive controller. An autopilot navigational state machine with appropriate transitioning between level and hover waypoints is also presented. …
Particle Filter Based Mosaicking For Forest Fire Tracking, Justin Mathew Bradley
Particle Filter Based Mosaicking For Forest Fire Tracking, Justin Mathew Bradley
Theses and Dissertations
Using autonomous miniature air vehicles (MAVs) is a cost-effective, simple method for collecting data about the size, shape, and location characteristics of a forest fire. However, noise in measurements used to compute pose (location and attitude) of the on-board camera leads to significant errors in the processing of collected video data. Typical methods using MAVs to track fires attempt to find single geolocation estimates and filter that estimate with subsequent observations. While this is an effective method of resolving the noise to achieve a better geolocation estimate, it reduces a fire to a single point or small set of points. …
Obstacle Avoidance For Small Unmanned Air Vehicles, Brandon R. Call
Obstacle Avoidance For Small Unmanned Air Vehicles, Brandon R. Call
Theses and Dissertations
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 …
Design Of An Autopilot For Small Unmanned Aerial Vehicles, Reed Siefert Christiansen
Design Of An Autopilot For Small Unmanned Aerial Vehicles, Reed Siefert Christiansen
Theses and Dissertations
This thesis presents the design of an autopilot capable of flying small unmanned aerial vehicles with wingspans less then 21 inches. The autopilot is extremely small and lightweight allowing it to fit in aircraft of this size. The autopilot features an advanced, highly autonomous flight control system with auto-launch and auto-landing algorithms. These features allow the autopilot to be operated by a wide spectrum of skilled and unskilled users. Innovative control techniques implemented in software, coupled with light weight, robust, and inexpensive hardware components were used in the design of the autopilot.
Autonomous Landing Of A Rotary Unmanned Aerial Vehicle In A Non-Cooperative Environment Using Machine Vision, Joshua Martin Hintze
Autonomous Landing Of A Rotary Unmanned Aerial Vehicle In A Non-Cooperative Environment Using Machine Vision, Joshua Martin Hintze
Theses and Dissertations
Landing an Unmanned Aerial Vehicle (UAV) is a non-trivial problem. Removing the ability to cooperate with the landing site further increases the complexity. This thesis develops a multi-stage process that allows a UAV to locate the safest landing site, and then land without a georeference. Machine vision is the vehicle sensor used to locate potential landing hazards and generate an estimated UAV position. A description of the algorithms, along with validation results, are presented. The thesis shows that software-simulated landing performs adequately, and that future hardware integration looks promising.
Implementation Issues Of Real-Time Trajectory Generation On Small Uavs, Derek B. Kingston
Implementation Issues Of Real-Time Trajectory Generation On Small Uavs, Derek B. Kingston
Theses and Dissertations
The transition from a mathematical algorithm to a physical hardware implementation is non-trivial. This thesis discusses the issues involved in the transition from the theory of real-time trajectory generation all the way through a hardware experiment. Documentation of the validation process as well as modifications to the existing theory as a result of hardware testing are treated at length. The results of hardware experimentation show that trajectory generation can be done in real-time in a manner facilitating coordination of multiple small UAVs.