Thesis (M.S. in Systems Technology)--Naval Postgraduate School, June 2005. / Thesis Advisor(s): James Ehlert. Includes bibliographical references (p. 173-175). Also available online.

Thesis (Ph. D.)--Aerospace Engineering, Georgia Institute of Technology, 2007. / Danielle Soban, Committee Member ; Dimitri Mavris, Committee Chair ; Alan Porter, Committee Member ; Gary Seng, Committee Member ; Daniel Schrage, Committee Member.

Thesis (MScEng)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: This dissertation presents the design and practical demonstration of a flight control system (FCS) that is capable of autonomously landing a fixed-wing, unmanned aerial vehicle (UAV) on a stationary platform aided by a high-precision differential global positioning system. This project forms part of on-going research with the end goal of landing a fixed-wing UAV on a moving platform (for example a ship’s deck) in windy conditions. The main aim of this project is to be able to land the UAV autonomously, safely and accurately on the runway. To this end, an airframe was selected and equipped with an avionics payload. The equipped airframe’s stability derivatives were analysed via AVL and the moment of inertia was determined by the double pendulum method. The aircraft model was developed in such a way that the specific force and moment model (high bandwidth) is split from the point-mass dynamics of the aircraft (low bandwidth) [1]. The advantage of modelling the aircraft according to this unique method, results in a design that has simple decoupled linear controllers. The inner-loop controllers control the high-bandwidth specific accelerations and roll-rate, while the outer-loop controllers control the low-bandwidth point-mass dynamics. The performance of the developed auto-landing flight control system was tested in software-in-the-loop (SIL) and hardware-in-the-loop (HIL) simulations. A Monte Carlo non-linear landing simulation analysis showed that the FCS is expected to land the aircraft 95% of the time within a circle with a diameter of 1.5m. Practical flight tests verified the theoretical results of the developed controllers and the project was concluded with five autonomous landings. The aircraft landed within a circle with a 7.5m radius with the aiming point at the centre of the circle. In the practical landings the longitudinal landing error dominated the landing performance of the autonomous landing system. The large longitudinal error resulted from a climb rate bias on the estimated climb rate and a shallow landing glide slope. / AFRIKAANSE OPSOMMING: Hierdie skripsie stel die ontwikkeling en praktiese demonstrasie van ʼn self-landdende onbemande vastevlerkvliegtuigstelsel voor, wat op ʼn stilstaande platform te lande kan kom met behulp van ʼn uiters akkurate globale posisionering stelsel. Die projek maak deel uit van ʼn groter projek, waarvan die doel is om ʼn onbemande vastevlerkvliegtuig op ʼn bewegende platform te laat land (bv. op ʼn boot se dek) in onstuimige windtoestande. Die hoofdoel van die projek was om die vliegtuig so akkuraat as moontlik op die aanloopbaan te laat land. ʼn Vliegtuigraamwerk is vir dié doel gekies wat met gepaste avionica uitgerus is. Die uitgeruste vliegtuig se aerodinamsie eienskappe was geanaliseer met AVL en die traagheidsmoment is deur die dubbelependulum metode bepaal. Die vliegtuigmodel is op so ‘n manier onwikkel om [1] die spesifieke krag en momentmodel (vinnige reaksie) te skei van die puntmassadinamiek (stadige reaksie). Die voordeel van hierdie wyse van modulering is dat eenvoudige ontkoppelde beheerders ontwerp kon word. Die binnelusbeheerders beheer die vinnige reaksie-spesifieke versnellings en die rol tempo van die vliegtuig. Die buitelusbeheerders beheer die stadige reaksie puntmassa dinamiek. Die vliegbeheerstelsel is in sagteware-in-die-lus en hardeware-in-die-lus simulasies getoets. Die vliegtuig se landingseienskappe is ondersoek deur die uitvoer van Monte Carlo simulasies, die simulasie resultate wys dat die vliegtuig 95% van die tyd binne in ʼn sirkel met ʼn diameter van 1.5m geland het. Praktiese vlugtoetse het bevestig dat die teoretiese uitslae en die prakties uitslae ooreenstem. Die vliegtuig het twee suksesvolle outomatiese landings uitgevoer, waar dit binne ʼn 7.5m-radius sirkel geland het, waarvan die gewenste landingspunt die middelpunt was. In die outomatiese landings is die longitudinale landingsfout die grootse. Die groot longitudinale landingsfout is as gevolg van ʼn afset op die afgeskatte afwaartse spoed en ʼn lae landings gradiënt.

M. Ing. / Solar powered UAV's have gained world wide attention with aircraft such as Solar Impulse and Quinetiq's Zephyr. UAV's in general are becomming increasingly popular, in 2006 80% of all US military ights over Iraq were UAV ights [38]. UAV's are the the most dynamic growth sector in the world aerospace industry having spent $3:4 billion in 2008 and is expected to be $5:8 billion in 2014. Solar Impulse has a budget of $94 million, Quinetiq has been awarded a $44:9 million contract to build 7 zephyrs. NASA has had several solar powered UAV projects. With advancements in solar and battery technologies solar powred UAV's are fast becomming a reality. The disadvantage of projects such as the Solar Impulse, Zephyr, Solong and Sky Sailor is they have extremely large budgets and have access to non commercial and highy specialized Chapter 1 | Problem Statement 10 products. The main purpose of the project is to develop a solar power system using only commercial products which can substancially increase the ight time of a UAV under sunny conditions. The project has several advantages: The project also provides a clean, green energy aspect. Because the energy provided by the solar cells is free and has no carbon footprint, the project is environmentally friendly; The project uses only commercially available products so it can easily be implemented and reproduced; The system developed for the project is not only limited to UAV's/ the project can be used in other applications such as Solar powered cars or robots. Due to the commercial nature of the big 4 solar aircraft information about their solar power systems is not easily available. The work presented here is an acedemic venture and will be freely available The project has many unknowns such as the size of the UAV, power requirements and available components. The research methodolgy used allows the unknowns to be determined using mathematical models and simulations. The models and simulations are further veri ed and altered accordingly to the actual implementation of the system. The project provides a step by step procedure to building a power system for a solar powered UAV. There are several building blocks in the project. Each building block forms a vital part of the system but can also be designed and implemented as a sigle entity. Only once each building block has achieved its own indavidual speci cations will they be integrated together to form the complete system. There are many risks and limitations within the project. The project is dependant on the type of UAV with respect to power requirements. Therefore the power system needs to provide as much solar power as possible to the UAV. If the available solar power is not su cient for level ight, the solar power must supliment the original power supply of the aircraft in a safe manner. There are many dangers when ying a UAV, if the UAV loses control it could potentially injure or even kill a person. Therefore outmost care needs to be taken to mitigate these risks. By the end of the project a solar power supply, capable of powering a UAV, will be delivered. With the given resources and the current state of technology the project should be a success.

How do technologies that remove warfighters from the front lines affect the frequency and intensity of military confrontations between states? Many scholars and policymakers fear that weapons that reduce the risks and costs of war – in blood and treasure – will lead states to resort to force more frequently during crises, destabilizing the international security environment. These concerns have featured prominently in debates surrounding the proliferation and use of remote warfighting technologies, such as drones. This project sets out to evaluate whether and how drones affect crisis escalation. Specifically, do drones allow decisionmakers to deploy military forces more frequently during interstate crises? Once deployed, how do these systems affect escalation dynamics? I argue that drones can help control escalation, raising questions about scholarly theories that suggest the world is more dangerous and less stable when technology makes conflict cheaper and less risky. At the core of this project is a theory of technology-enabled escalation control. The central argument is that technologies like drones that remove friendly forces from the battlefield may lead states to use force more frequently, but decrease the likelihood of escalation when used in lieu of inhabited platforms. More specifically, these technologies lower the political barriers to initiating military operations during crises, primarily by eliminating the risk of friendly force casualties and the associated domestic political consequences for launching military operations. At the same time, removing personnel from harm’s way may reduce demand for escalatory reprisals after remotely operated systems are lost to hostile action. Drones can also help to mitigate escalatory spirals by collecting intelligence that overcomes information asymmetries that often contribute to armed conflict, helping facilitate more measured decision-making and tailored targeting of enemy forces. By more fully considering how technology affects escalatory dynamics after the initial use of force, technology-enabled escalation control theory advances our understanding of the link between technology and conflict. I test the theory using a multi-method approach that combines case studies with original experiments embedded in surveys fielded on public and military samples. The dissertation also introduces a new research method for international relations research: experimental manipulations embedded in wargames with military participants. In Chapter 1 and 2, I define the concept of crisis escalation and review the literature that examines the effect of technology on escalation and conflict dynamics. I then introduce the theory of technology-enabled escalation control and outline four mechanisms that undergird the theory – increased initiation, tempered/tailored targeting, restrained retaliation, and amplified aggression. Each of these hypothesized mechanisms describes ways in which emerging technologies can prevent crises from escalating into broader or more intense conflicts. Chapter 3 describes each component of the multi-method research design that I use to test the theory in Chapters 4 through 7. Chapter 4 uses experiments embedded in surveys and wargames to assess whether and how drones allow states to more frequently initiate military operations. Chapter 5 tests whether drones enable decisionmakers to control escalation by restraining retaliation after attacks on a state’s drones. Chapter 6 and 7 test the theory in the context of U.S drone use during the Cold War and Israeli drone use from the 1960s through late-2010s. The findings of these empirical tests provide strong support for technology-enabled escalation control. In Chapter 8, I conclude with a summary of the analysis and test the generalizability of the theory beyond the state use of drones. I find that tenets of technology-enabled escalation control explain escalation dynamics associated with U.S. cyber operations against North Korea and Hezbollah’s use of drones against Israel and during the Syrian Civil War. The chapter also maps out pathways for future research and identifies policy implications. My findings suggest the growing proliferation of drones will increase the frequency of military confrontations during crises, yet these confrontations are unlikely to escalate. Even though drones may help control escalation, clearer doctrine, rules of engagement, and international agreements to govern their use will help to further avoid crisis escalation and conflict.

Land cover classification is necessary for understanding the state of the surface of the Earth at varying regions of interest. Knowledge of the Earth’s surface is critical in land-use planning, especially for the project study area Jupiter Inlet Lighthouse Outstanding Natural Area, where various vegetation, wild-life, and cultural components rely on adequate land-cover knowledge. The purpose of this research is to demonstrate the capability of UAV true color imagery for land cover classification. In addition to the objective of land cover classification, comparison of varying spatial resolutions of the imagery will be analyzed in the accuracy assessment of the output thematic maps. These resolutions will also be compared at varying training sample sizes to see which configuration performed best. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2020. / FAU Electronic Theses and Dissertations Collection

In this thesis, we conduct a preliminary study on the controller design for directional antenna devices carried by drones. The goal of the control system is to ensure the best alignment between two directional antennas so as to enhance the performance of air-to-air communication between the drones. The control system at the current stage relies on the information received from GPS devices. The control system includes two loops: velocity loop and position loop to suppress wind disturbances and to assure the alignment of two directional antennae. The simulation and animation of directional antennae alignment control for two-randomly moving drones was developed using SIMULINK. To facilitate RSSI-based antenna alignment control to be conducted in the future work, a study on initial scanning techniques is also included at the end of this thesis.

Grain protein content is an essential component to producing a profitable Hard Red Spring Wheat (HRSW) (Triticum aestivum L.) crop in the northern Great Plains. Growers can increase grain protein content through in-season N fertilization; however, the cost of these applications may outweigh the benefits. Predicting the grain protein content of early-season HRSW would give growers crucial information as they decide whether to apply in-season fertilizer to boost grain protein content. This research encompasses three studies; two of which aim to predict grain protein content with hand-held and aerial sensors respectively, and a third, which investigates the optimal rate, timing, and source of N fertilizer to boost grain protein content. Results of these experiments seemed to be greatly influenced by environmental factors. Findings of this research suggest that an in-season N application should be used for ameliorative purposes and not as a regular practice. / Minnesota Research and Promotion Council / Minnesota Association of Wheat Growers

Cyber-Physical Systems (CPSs) are critical to many aspects of our daily lives. Autonomous cars, life saving medical devices, drones for package delivery, and robots for manufacturing are all prime examples of CPSs. The dual cyber/physical operating nature and highly integrated feedback control loops of CPSs means that they inherit security problems from traditional computing systems (e.g., software vulnerabilities, hardware side-channels) and physical systems (e.g., theft, tampering), while additionally introducing challenges of their own. The challenges to achieving security for CPSs stem not only from the interaction of the cyber and physical domains, but from the additional pressures of resource constraints imposed due to cost, limited energy budgets, and real-time nature of workloads. Due to the tight resource constraints of CPSs, there is often little headroom to devote for security. Thus, there is a need for low overhead deployable solutions to harden resource constrained CPSs. This dissertation shows that security can be effectively integrated into resource constrained cyber-physical system devices by leveraging fundamental physical properties, & tailoring and extending age-old abstractions in computing. To provide context on the state of security for CPSs, this document begins with the development of a unifying framework that can be used to identify threats and opportunities for enforcing security policies while providing a systematic survey of the field. This dissertation characterizes the properties of CPSs and typical components (e.g., sensors, actuators, computing devices) in addition to the software commonly used. We discuss available security primitives and their limitations for both hardware and software. In particular, we focus on software security threats targeting memory safety. The rest of the thesis focuses on the design and implementation of novel, deployable approaches to combat memory safety on resource constrained devices used by CPSs (e.g., 32-bit processors and microcontrollers). We first discuss how cyber-physical system properties such as inertia and feedback can be used to harden software efficiently with minimal modification to both hardware and software. We develop the framework You Only Live Once (YOLO) that proactively resets a device and restores it from a secure verified snapshot. YOLO relies on inertia, to tolerate periods of resets, and on feedback to rebuild state when recovering from a snapshot. YOLO is built upon a theoretical model that is used to determine safe operating parameters to aid a system designer in deployment. We evaluate YOLO in simulation and two real-world CPSs, an engine and drone. Second, we explore how rethinking of core computing concepts can lead to new fundamental abstractions that can efficiently hide performance overheads usually associated with hardening software against memory safety issues. To this end, we present two techniques: (i) The Phantom Address Space (PAS) is a new architectural concept that can be used to improve N-version systems by (almost) eliminating the overheads associated with handling replicated execution. Specifically, PAS can be used to provide an efficient implementation of a diversification concept known as execution path randomization aimed at thwarting code-reuse attacks. The goal of execution path randomization is to frequently switch between two distinct program variants forcing the attacker to gamble on which code to reuse. (ii) Cache Line Formats (Califorms) introduces a novel method to efficiently store memory in caches. Califorms makes the novel insight that dead spaces in program data due to its memory layout can be used to efficiently implement the concept of memory blacklisting, which prohibits a program from accessing certain memory regions based on program semantics. Califorms not onlyconsumes less memory than prior approaches, but can provide byte-granular protection while limiting the scope of its hardware changes to caches. While both PAS and Califorms were originally designed to target resource constrained devices, it's worth noting that they are widely applicable and can efficiently scale up to mobile, desktop, and server class processors. As CPSs continue to proliferate and become integrated in more critical infrastructure, security is an increasing concern. However, security will undoubtedly always play second fiddle to financial concerns that affect business bottom lines. Thus, it is important that there be easily deployable, low-overhead solutions that can scale from the most constrained of devices to more featureful systems for future migration. This dissertation is one step towards the goal of providing inexpensive mechanisms to ensure the security of cyber-physical system software.

Fusarium is one of the most important genera of fungi on earth. Many species of Fusarium are well-suited for atmospheric dispersal, yet little is known about their aerobiology. Previous research has shown that large-scale features known as atmospheric transport barriers (Lagrangian coherent structures) guide the transport and mixing of atmospheric populations of Fusarium. The overall goal of this work is to expand our knowledge on the movement and structure of atmospheric populations of Fusarium. The first objective was to monitor changes in colony forming units (CFUs) in atmospheric populations of Fusarium over small time intervals (10 min to several hours). We hypothesized that consecutive collections of Fusarium with unmanned aerial vehicles (UAVs) demonstrate small variations in colony counts. To test this hypothesis, sampling devices on UAVs were separated into two groups, four inner sampling devices opened during the first 10 minutes and four outer sampling devices opened during the second 10 minutes. Results indicated that (1) consecutive collections of Fusarium at 100 m demonstrated small variations in counts and (2) the similarity between collections decreased as the time between sampling intervals increased. The second objective was to determine the structure of atmospheric populations of Fusarium species and relate this to potential source regions. We hypothesized that diverse atmospheric populations of Fusarium are associated with multiple source regions. To test this hypothesis, Fusarium samples were collected with UAVs and identified to the level of species by sequencing a portion of the translation elongation factor 1-alpha gene (TEF-1•). Potential source regions were identified using the atmospheric transport model HYSPLIT. Results indicated that (1) diverse atmospheric populations of Fusarium appeared to be associated with multiple source regions, and (2) the number of Fusarium species collected with UAVs increased with back-trajectory distance of the sampled air. The third objective was to examine the associations between concentrations of populations of Fusarium at ground level (1 m) and in the lower atmosphere (100 m). We hypothesized that concentrations of Fusarium in the atmosphere vary between 1m and 100m. To test this hypothesis, Fusarium was collected with a Burkard volumetric sampler (BVS) and UAVs. Colony counts were converted to spore concentrations (spores per cubic meter of air). Sampling efficiency was used to correct spore concentrations. Results indicated that (1) the distribution of spore concentrations was similar for both samplers over different times of the day, (2) spore concentrations were generally higher in the fall, spring, and summer, and lower in the winter, and (3) spore concentrations were generally higher with BVS samplers than those with UAVs for both hourly and seasonal data. The fourth objective was to assess the ability of strains of Fusarium collected in the lower atmosphere to cause plant disease. We hypothesized that certain isolates of Fusarium collected with UAVs cause plant diseases. To test this hypothesis, we randomly selected isolates of three different species (F. circinatum, F. avenaceum, and F. sporotrichioides) of Fusarium collected with UAVs to inoculate three different hosts (wheat, corn, and pine). Known Fusarium strains were obtained from J. Leslie at Kansas State University as controls. Results indicated showed that the three different isolates tested were able to cause plant diseases in three different hosts (wheat, corn, and pine), confirming that these were potential agents of disease. This work sets the stage for future work examining potential source regions, transport distances, and seasonal patterns of Fusarium. An increased understanding of the dynamics and population structure of plant pathogenic Fusarium in the lower atmosphere is essential for predicting the spread of plant disease and optimizing disease management strategies in the future. / Ph. D.