This study examines the grower’s decision to invest in precision agriculture technologies especially in-season variable rate nitrogen applications based on NDVI data collected from UAVs. NDVI, yield, soil, and other field data were collected from multiple corn and wheat fields located throughout North Dakota. Each field was divided into management zones to determine profitability of utilizing the technology based on in-season nitrogen applications for the grower’s field practice, high, low, and no applications. Results show that using the NDVI data collected from UAVs can be profitable when the grower decides to make the decision to apply nitrogen in a sidedress application.

Equally discomforting is the PlayStation mentality that surrounds drone killings. Young military personnel raised on a diet of video games now kill real people remotely using joysticks. Far removed from the human consequences of their actions, how will this generation of fighters value the right to life? How will commanders and policy makers keep themselves immune from the deceptively antiseptic nature of drone killings? Will killing be a more attractive option than capture? Will the standards of intelligence gathering justify a killing slip? Will the number of acceptable collateral civilian deaths increase? / Prepared under the supervision of Mr Gus Waschefort at the International criminal court, The Hague, Netherlands / Thesis (LLM (Human Rights and Democratisation in Africa)) -- University of Pretoria, 2011. / http://www.chr.up.ac.za/ / nf2012 / Centre for Human Rights / LLM

Ducted fan vehicles possess a superior ability to maximize payload capacity while minimizing vehicle size. Their ability to both hover and fly at high speed is a key advantage for information-gathering missions, particularly when close proximity to a target is essential. However, the ducted fan's aerodynamic characteristics pose difficulties for stable vehicle flight and therefore require complex control algorithms. In particular, they exhibit a large nose-up pitching moment during wind gusts and when transitioning from hover to forward flight. Understanding ducted fan aerodynamic behavior and how it can be altered through flow control techniques are the two prime objectives of this work. This dissertation provides a new paradigm for modeling the ducted fan's nonlinear behavior and new methods for changing the duct aerodynamics using active flow control. Steady and piezoelectric synthetic jet blowing are employed in the flow control concepts and are compared. The new aerodynamic model captures the nonlinear characteristics of the force, moment, and power data for a ducted fan, while representing these terms in a set of simple equations. The model attains excellent agreement with current and legacy experimental data using twelve non-dimensional constants. Synthetic jet actuators (SJA) have potential for use in flow control applications in UAVs with limited size, weight, and power budgets. Piezoelectric SJAs for a ducted fan vehicle were developed through two rounds of experimental designs. The final SJA design attained peak jet velocities in the range of 225 ft/sec (69 m/s) for a 0.03â x 0.80â rectangular slot. To reduce the magnitude of the nose-up pitching moment in cross-winds, two flow control concepts were explored: flow separation control at the duct lip, and flow turning at the duct trailing edge using a CoandÄ surface. Both concepts were experimentally proven to be successful. Synthetic jets and steady jets were capable of modifying the ducted fan flow to reduce pitching moment, but some cases required high values of steady blowing to create significant responses. Triggering leading edge separation on the duct lip was one application where synthetic jets showed comparable performance to steady jets operating at a blowing coefficient an order of magnitude higher. / Ph. D.

This thesis aimed to assess the feasibility of using an off-the-shelf virtual reality tracking system as a low cost precision pose estimation solution for robotic operations in both indoor and outdoor environments. Such a tracking solution has the potential of assisting critical operations related to planetary exploration missions, parcel handling/delivery, and wildfire detection/early warning systems. The boom of virtual reality experiences has accelerated the development of various low-cost, precision indoor tracking technologies. For the purpose of this thesis we choose to adapt the SteamVR Lighthouse system developed by Valve, which uses photo-diodes on the trackers to detect the rotating IR laser sheets emitted from the anchored base stations, also known as lighthouses. Some previous researches had been completed using the first generation of lighthouses, which has a few limitations on communication from lighthouses to the tracker. A NASA research has cited poor tracking performance under sunlight. We choose to use the second generation lighthouses which has improved the method of communication from lighthouses to the tracker, and we performed various experiments to assess their performance outdoors, including under sunlight. The studies of this thesis have two stages, the first stage focused on a controlled, indoor environment, having an Unmanned Aerial Vehicle (UAS) perform repeatable flight patterns and simultaneously tracked by the Lighthouse and a reference indoor tracking system, which showed that the tracking precision of the lighthouse is comparable to the industrial standard indoor tracking solution. The second stage of the study focused on outdoor experiments with the tracking system, comparing UAS flights between day and night conditions as well as positioning accuracy assessments with a CNC machine under indoor and outdoor conditions. The results showed matching performance between day and night while still comparable to industrial standard indoor tracking solution down to centimeter precision, and matching simulated CNC trajectory down to millimeter precision. There is also some room for improvement in regards to the experimental method and equipment used, as well as improvements on the tracking system itself needed prior to adaptation in real-world applications. / Master of Science / This thesis aimed to assess the feasibility of using an off-the-shelf virtual reality tracking system as a low cost precision pose estimation solution for robotic operations in both indoor and outdoor environments. Such a tracking solution has the potential of assisting critical operations related to planetary exploration missions, parcel handling/delivery, and wildfire detection/early warning systems. The boom of virtual reality experiences has accelerated the development of various low-cost, precision indoor tracking technologies. For the purpose of this thesis we choose to adapt the SteamVR Lighthouse system developed by Valve, which uses photo-diodes on the trackers to detect the rotating IR laser sheets emitted from the anchored base stations, also known as lighthouses. Some previous researches had been completed using the first generation of lighthouses, which has a few limitations on communication from lighthouses to the tracker. A NASA research has cited poor tracking performance under sunlight. We choose to use the second generation lighthouses which has improved the method of communication from lighthouses to the tracker, and we performed various experiments to assess their performance outdoors, including under sunlight. The studies of this thesis have two stages, the first stage focused on a controlled, indoor environment, having an Unmanned Aerial Vehicle (UAS) perform repeatable flight patterns and simultaneously tracked by the Lighthouse and a reference indoor tracking system, which showed that the tracking precision of the lighthouse is comparable to the industrial standard indoor tracking solution. The second stage of the study focused on outdoor experiments with the tracking system, comparing UAS flights between day and night conditions as well as positioning accuracy assessments with a CNC machine under indoor and outdoor conditions. The results showed matching performance between day and night while still comparable to industrial standard indoor tracking solution down to centimeter precision, and matching simulated CNC trajectory down to millimeter precision. There is also some room for improvement in regards to the experimental method and equipment used, as well as improvements on the tracking system itself needed prior to adaptation in real-world applications.

As science and technology continue to advance, innovative developments in transportation can enhance product safety and security for the benefit and welfare of society. The federal government requires every commercial truck to be inspected before each trip. This pre-trip inspection ensures the safe mechanical condition of each vehicle before it is used. An Unmanned Aerial Vehicle (UAV) could be used to provide an automated inspection, thus reducing driver workload, inspection costs and time while increasing inspection accuracy. This thesis develops a primary component of the algorithm that is required to implement UAV pre-trip inspections for commercial trucks using an android-based application. Specifically, this thesis provides foundational work of providing stable height control in an outdoor environment using a laser sensor and an android flight control application that includes take-off, landing, throttle control, and real-time video transmission. The height algorithm developed is the core of this thesis project. Phantom 2 Vision+ uses a pressure sensor to calculate the altitude of the drone for height stabilization. However, these altitude readings do not provide the precision required for this project. Rather, the goal of autonomously controlling height with great precision necessitated the use of a laser rangefinder sensor in the development of the height control algorithm. Another major contribution from this thesis research is to extend the limited capabilities of the DJI software development kit in order to provide more sophisticated control goals without modifying the drone dynamics. The results of this project are also directly applicable to a number of additional uses of drones in the transportation industry.

Approved for public release; distribution in unlimited. / This study analyzes the effective use of multiple unmanned aerial vehicles (UAVs) for the Navy's Surface Search and Control mission. In the future, the Navy hopes to leverage the capabilities of a family of UAVs to provide increased situational awareness in the maritime environment. This family of UAVs includes a Broad Area Maritime Surveillance (BAMS) UAV and Vertical Take-Off UAVs (VTUAVs). The concepts of operations for how these UAVs work together have yet to be determined. Questions exist about the best number of UAVs, types of UAVs, and tactics that will provide increased capabilities. Through modeling and agent-based simulation, this study explores the validity of future UAV requirements and provides insights into the effectiveness of different UAV combinations. For the scenarios modeled, the best UAV combination is BAMS plus two or three VTUAVs. However, analysis shows that small numbers of VTUAVs can perform as well without BAMS as they do with BAMS. For combinations with multiple UAVs, BAMS proves to be a valuable asset that not only reduces the number of missed classifications, but greatly improves the amount of coverage on all contacts in the maritime environment. BAMS tactics have less effect than the mere presence of BAMS itself. / Lieutenant, United States Navy

Approved for public release, distribution is unlimited / This thesis is part of an ongoing research conducted at the Naval Postgraduate School to achieve the autonomous shipboard landing of Unmanned Aerial Vehicles (UAV). Two main problems are addressed in this thesis. The first is to establish communication between the UAV's ground station and the Autonomous Landing Flight Control Computer effectively. The second addresses the design and implementation of an autonomous landing controller using classical control techniques. Device drivers for the sensors and the communications protocol were developed in ANSI C. The overall system was implemented in a PC104 computer running a real-time operating system developed by The Mathworks, Inc. Computer and hardware in the loop (HIL) simulation, as well as ground test results show the feasibility of the algorithm proposed here. Flight tests are scheduled to be performed in the near future. / Lieutenant Junior Grade, Mexican Navy

Approved for public release; distribution is unlimited / An increasing number of unmanned vehicles (UV) are being incorporated into maritime operations as organic elements of Expeditionary and Carrier Strike Groups for development of the recognized maritime picture. This thesis develops an analytically-based planning aid for allocating UVs to missions. Inputs include the inventory of UVs, sensors, their performance parameters, and operational scenarios. Operations are broken into mission critical functions: detection, identification, and collection. The model output assigns aggregated packages of UVs and sensors to one of the three functions within named areas of interest. A spreadsheet model uses conservative time-speed-distance calculations, and simplified mathematical models from search theory and queuing theory, to calculate measures of performance for possible assignments of UVs to missions. The spreadsheet model generates a matrix as input to a linear integer program assignment model which finds the best assignment of UVs to missions based on the user inputs and simplified models. The results provide the mission planner with quantitatively-based recommendations for unmanned vehicle mission tasking in challenging scenarios. / Lieutenant, United States Navy

Approved for public release, distribution is unlimited / In urbanized terrain, radiowave propagation is subjected to fading on large-scales and smallscales that would impede on the quality and reliability of data link transmission. This would have implications in many military applications. One example is the performance of unmanned aerial vehicle (UAV) data and communications links in complex urban environments. The purpose of this research is to study the effectiveness of diversity techniques on the performance of urban UAV data and communications links. The techniques investigated were spatial, polarization, and angle diversities. The ray tracing software, Urbana Wireless Toolset, was used in the modeling and simulation process. The various combinations of diversity techniques were simulated using a realistic urban city model. For the few transmit-receive geometries examined, it was found that angle diversity with a directive antenna provided the greatest increase in signal strength relative to the no diversity case. / Civilian, Singapore DOD

The role of vision as an additional sensing mechanism has received a lot of attention in recent years in the context of autonomous flight applications. Modern Unmanned Aerial Vehicles (UAVs) are equipped with vision sensors because of their light-weight, low-cost characteristics and also their ability to provide a rich variety of information of the environment in which the UAVs are navigating in. The problem of vision based autonomous flight is very difficult and challenging since it requires bringing together concepts from image processing and computer vision, target tracking and state estimation, and flight guidance and control. This thesis focuses on the adaptive state estimation, guidance and control problems involved in vision-based formation flight. Specifically, the thesis presents a composite adaptation approach to the partial state estimation of a class of nonlinear systems with unmodeled dynamics. In this approach, a linear time-varying Kalman filter is the nominal state estimator which is augmented by the output of an adaptive neural network (NN) that is trained with two error signals. The benefit of the proposed approach is in its faster and more accurate adaptation to the modeling errors over a conventional approach. The thesis also presents two approaches to the design of adaptive guidance and control (G&C) laws for line-of-sight formation flight. In the first approach, the guidance and autopilot systems are designed separately and then combined together by assuming time-scale separation. The second approach is based on integrating the guidance and autopilot design process. The developed G&C laws using both approaches are adaptive to unmodeled leader aircraft acceleration and to own aircraft aerodynamic uncertainties. The thesis also presents theoretical justification based on Lyapunov-like stability analysis for integrating the adaptive state estimation and adaptive G&C designs. All the developed designs are validated in nonlinear, 6DOF fixed-wing aircraft simulations. Finally, the thesis presents a decentralized coordination strategy for vision-based multiple-aircraft formation control. In this approach, each aircraft in formation regulates range from up to two nearest neighboring aircraft while simultaneously tracking nominal desired trajectories common to all aircraft and avoiding static obstacles.