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Articles 1 - 30 of 32
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Design And Implementation Of A Unified Command And Control Architecture For Multiple Cooperative Unmanned Vehicles Utilizing Commercial Off The Shelf Components, Jeremy Gray
Theses and Dissertations
Small unmanned systems provide great utility to military applications due to their portable and expendable design. These systems are, however, costly to develop, produce, and maintain, making it desirable to integrate available commercial off the shelf (COTS) components. This research investigates the integration of COTS components through the development of a modular unified command and control (C2) architecture for heterogeneous and homogeneous vehicle teams to accomplish formation flocking and communication relay scenarios. A vehicle agnostic architecture was developed to be applied across different vehicle platforms, different vehicle combination, and different cooperative missions. COTS components consisting primarily of open source hardware …
Optimal Uas Assignments And Trajectories For Persistent Surveillance And Data Collection From A Wireless Sensor Network, Nidal M. Jodeh
Optimal Uas Assignments And Trajectories For Persistent Surveillance And Data Collection From A Wireless Sensor Network, Nidal M. Jodeh
Theses and Dissertations
This research developed a method for multiple Unmanned Aircraft Systems (UAS) to efficiently collect data from a Wireless Sensor Networks (WSN). WSN are composed of any number of fixed, ground-based sensors that collect and upload local environmental data to over flying UAS. The three-step method first uniquely assigns aircraft to specific sensors on the ground. Second, an efficient flight path is calculated to minimize the aircraft flight time required to verify their assigned sensors. Finally, sensors reporting relatively higher rates of local environmental activity are re-assigned to dedicated aircraft tasked with concentrating on only those sensors. This work was sponsored …
Adaptive Automation Design And Implementation, Jason M. Bindewald
Adaptive Automation Design And Implementation, Jason M. Bindewald
Theses and Dissertations
Automations allow us to reduce the need for humans in certain environments, such as auto-pilot features on unmanned aerial vehicles. However, some situations still require human intervention. Adaptive automation is a research field that enables computer systems to adjust the amount of automation by taking over tasks from or giving tasks back to the user. This research develops processes and insights for adaptive automation designers to take theoretical adaptive automation ideas and develop them into real-world adaptive automation system. These allow developers to design better automation systems that recognize the limits of computers systems, enabling better designs for systems in …
System Architecture Of Small Unmanned Aerial System For Flight Beyond Visual Line-Of-Sight, Kwee Siam Seah
System Architecture Of Small Unmanned Aerial System For Flight Beyond Visual Line-Of-Sight, Kwee Siam Seah
Theses and Dissertations
Small Unmanned Aerial Systems (UAS) have increasingly been used in military application. The application in expanding scope of operations has pushed existing small UAS beyond its designed capabilities. This resulted in frequent modifications or new designs. A common requirement in modification or new design of small UAS is to operate beyond visual Line-Of-Sight (LOS) of the ground pilot. Conventional military development for small UAS adopts a design and built approach. Modification of small Remote Control (RC) aircraft, using Commercial-Off-The Shelf (COTS) equipment, offers a more economical alternative with the prospect of shorter development time compared to conventional approach. This research …
A Method To Predict Compressor Stall In The Tf34-100 Turbofan Engine Utilizing Real-Time Performance Data, Shuxiang A. Li, Trevor G. Jones
A Method To Predict Compressor Stall In The Tf34-100 Turbofan Engine Utilizing Real-Time Performance Data, Shuxiang A. Li, Trevor G. Jones
Theses and Dissertations
The Air Force current operations continue to undergo significant changes compelled by decreasing fiscal appropriations, aging aircraft, and personnel drawdown. The Air Force must effectively improve current maintenance operations in part to deal with these challenges. This study will explore the area of the A-10 aircraft fleet's TF34-100 high-pass turbo-fan engine sensor data to seek its deterioration modelling and prognostics capability. In futurity this will allow for achievement of greater confidence in predicting the compressor stall which leads to engine performance deterioration and a costly repair in maintenance. By utilizing an innovative method to forecast the probability of compressor stall, …
Generation Of Strategies For Environmental Deception In Two-Player Normal-Form Games, Howard E. Poston
Generation Of Strategies For Environmental Deception In Two-Player Normal-Form Games, Howard E. Poston
Theses and Dissertations
Methods of performing and defending against deceptive actions are a popular field of study in game theory; however, the focus is mostly on action deception in turn-based games. This work focuses on developing strategies for performing environmental deception in two-player, strategic-form games. Environmental deception is defined as deception where one player has the ability to change the other's perception of the state of the game through modification of their perception of the game's payoff matrix, similar to the use of camouflage. The main contributions of this research are an expansion of the definition of the stability of a Nash equilibrium …
Theoretical Limits Of Lunar Vision Aided Navigation With Inertial Navigation System, David W. Jones
Theoretical Limits Of Lunar Vision Aided Navigation With Inertial Navigation System, David W. Jones
Theses and Dissertations
The precision navigation capabilities of the Global Positioning System (GPS) are used extensively within US military operations. However, GPS is highly vulnerable to intentional and unintentional external interference. Therefore, a need exists to develop a non-GPS precision navigation method to operate in GPS degraded environments. This research effort presents the theoretical limits of a precision navigation method based on an inertial navigation system (INS) aided by angle measurements with respect to lunar surface features observed by a fixed camera. To accomplish this task, an extended Kalman filter (EKF) was implemented to estimate INS drift errors and bring in simulated lunar …
Precision Relative Positioning For Automated Aerial Refueling From A Stereo Imaging System, Kyle P. Werner
Precision Relative Positioning For Automated Aerial Refueling From A Stereo Imaging System, Kyle P. Werner
Theses and Dissertations
The United States Air Force relies upon aerial refueling to fulfill its missions. Unmanned aerial systems (UAS) and remotely piloted aircraft (RPA) do not currently have access to this capability due to the lack of an on-board pilot to safely maintain a refueling position. This research examines stereo vision for precision relative navigation in order to accomplish the Automated Aerial Refueling (AAR) task. Previous work toward an AAR solution has involved the use of Differential Global Positioning (DGPS), Light Detection and Ranging (LiDAR), and monocular vision. This research aims to leverage organic systems in future aircraft to compliment these solutions. …
An Inventory And Safety Stock Analysis Of Air Force Medical Service Pharmaceuticals, Blake Smith
An Inventory And Safety Stock Analysis Of Air Force Medical Service Pharmaceuticals, Blake Smith
Theses and Dissertations
A significant challenge facing the Air Force Medical Service (AFMS) Military Treatment Facilities (MTFs) is the perishability costs associated with its pharmaceutical stock. During a two year time period, the AFMS returned expired or nearly expired pharmaceuticals valued at over $23,000,000. In response to the waste represented by pharmaceutical perishability cost, this thesis analyzes the historical inventory management decisions of 173 MTF/pharmaceutical combinations and proposes an alternative inventory control policy to reduce perishability costs. Based on the critical nature of pharmaceuticals and importance of generating high patient satisfaction, the proposed alternative inventory control system was required to be cognizant of …
Examining The Return On Investment Of Test And Evaluation, Nathan C. Smith
Examining The Return On Investment Of Test And Evaluation, Nathan C. Smith
Theses and Dissertations
This research examined the return on investment of Department of Defense test and evaluation. The thesis analyzed the return on investment of the cost avoidance achieved if an issue discovered late in the program had been discovered and corrected during developmental test and evaluation. The methodology utilized two case study examples from the Joint Primary Training Aircraft System to calculate the potential cost avoidance and the potential return on investment if the program had discovered and corrected the issues during developmental test and evaluation. The result of one case was a 9,260% return on investment. The other case results ranged …
Initial Implementation And Testing Of A Tightly-Coupled Imu/Pseudolite System, James E. C. Kawecki
Initial Implementation And Testing Of A Tightly-Coupled Imu/Pseudolite System, James E. C. Kawecki
Theses and Dissertations
Currently, the 746th Test Squadrons (746th TS) Central Inertial and GPS Test Facility (CIGTF) operates one of the most accurate truth reference systems, called the CIGTF Reference System (CRS). CIGTF will be replacing the CRS with a new references system called UHARS (Ultra High Accuracy Reference System). UHARS will differ from CRS by adding the ability to use a non-GPS pseudolite system, as a new measurement source. This research effort describes the design of the extended Kalman filter which is developed in AFIT's SPIDER filter framework which implements a tightly-coupled pseudolite/INS filter.
Modeling Navigation System Performance Of A Satellite-Observing Star Tracker Tightly Integrated With An Inertial Measurement Unit, Scott J. Pierce
Modeling Navigation System Performance Of A Satellite-Observing Star Tracker Tightly Integrated With An Inertial Measurement Unit, Scott J. Pierce
Theses and Dissertations
This dissertation evaluates a navigation system using satellite observations from a star tracker tightly-integrated with an inertial measurement unit (IMU) and a barometric altimeter using an extended Kalman filter. The star tracker measurement accuracy of a satellite is derived. Several system configurations are simulated comparing the performance of the estimate with respect to system parameters of the IMU, and star tracker, as well as comparing performance when providing a remote sensor satellite ephemeris error correction. Experimental observations are used to evaluate the model performance. Additionally, power requirements were calculated for a satellite signal operating in imaging bands, such that a …
Counter Weapon Control, Brian J. Roadruck
Counter Weapon Control, Brian J. Roadruck
Theses and Dissertations
In this work, pursuit-evasion differential game theory is applied to the target defense scenario. The targets, attackers, and the defenders positional information is assumed to be known to the players. With positional information, a computational efficient method of strategy synthesis can be derived applying a differential game theory approach. We demonstrate that when non-optimal strategies are employed by one of the players, e.g. Line Of Sight guidance, the outcome will favor the players that employ the optimal strategy given by the solution of the pursuit-evasion differential game.
Characterizing Multiple Wireless Sensor Networks For Large-Scale Radio Tomography, Tan Van
Characterizing Multiple Wireless Sensor Networks For Large-Scale Radio Tomography, Tan Van
Theses and Dissertations
Radio Tomographic Imaging (RTI) is an emerging Device-Free Passive Localization (DFPL) technology that uses a collection of cheap wireless transceivers to form a Wireless Sensor Network (WSN). Unlike device-based active localization, DFPL does not require a target of interest to be wearing any kind of device. The basic concept of RTI utilizes the changes in Received Signal Strength (RSS) between the links of each transceiver to create an attenuation image of the area. This image can then be used for target detection, tracking, and localization. Each transceiver in the WSN must transmit sequentially to prevent collisions. This is not a …
On The Integration Of Medium Wave Infrared Cameras For Vision-Based Navigation, Justin S. Tharp
On The Integration Of Medium Wave Infrared Cameras For Vision-Based Navigation, Justin S. Tharp
Theses and Dissertations
The ubiquitous nature of GPS has fostered its widespread integration of navigation into a variety of applications, both civilian and military. One alternative to ensure continued flight operations in GPS-denied environments is vision-aided navigation, an approach that combines visual cues from a camera with an inertial measurement unit (IMU) to estimate the navigation states of a moving body. The majority of vision-based navigation research has been conducted in the electro-optical (EO) spectrum, which experiences limited operation in certain environments. The aim of this work is to explore how such approaches extend to infrared imaging sensors. In particular, it examines the …
Urban Environment Navigation With Real-Time Data Utilizing Computer Vision, Inertial, And Gps Sensors, Johnathan L. Rohde
Urban Environment Navigation With Real-Time Data Utilizing Computer Vision, Inertial, And Gps Sensors, Johnathan L. Rohde
Theses and Dissertations
The purpose of this research was to obtain a navigation solution that used real data, in a degraded or denied global positioning system (GPS) environment, from low cost commercial o the shelf sensors. The sensors that were integrated together were a commercial inertial measurement unit (IMU), monocular camera computer vision algorithm, and GPS. Furthermore, the monocular camera computer vision algorithm had to be robust enough to handle any camera orientation that was presented to it. This research develops a visual odometry 2-D zero velocity measurement that is derived by both the features points that are extracted from a monocular camera …
Leveraging Human Insights By Combining Multi-Objective Optimization With Interactive Evolution, Joshua R. Christman
Leveraging Human Insights By Combining Multi-Objective Optimization With Interactive Evolution, Joshua R. Christman
Theses and Dissertations
Deceptive fitness landscapes are a growing concern for evolutionary computation. Recent work has shown that combining human insights with short-term evolution has a synergistic effect that accelerates the discovery of solutions. While humans provide rich insights, they fatigue easily. Previous work reduced the number of human evaluations by evolving a diverse set of candidates via intermittent searches for novelty. While successful at evolving solutions for a deceptive maze domain, this approach lacks the ability to measure what the human evaluator identifies as important. The key insight here is that multi-objective evolutionary algorithms foster diversity, serving as a surrogate for novelty, …
Estimating Single And Multiple Target Locations Using K-Means Clustering With Radio Tomographic Imaging In Wireless Sensor Networks, Jeffrey K. Nishida
Estimating Single And Multiple Target Locations Using K-Means Clustering With Radio Tomographic Imaging In Wireless Sensor Networks, Jeffrey K. Nishida
Theses and Dissertations
Geolocation involves using data from a sensor network to assess and estimate the location of a moving or stationary target. Received Signal Strength (RSS), Angle of Arrival (AoA), and/or Time Difference of Arrival (TDoA) measurements can be used to estimate target location in sensor networks. Radio Tomographic Imaging (RTI) is an emerging Device-Free Localization (DFL) concept that utilizes the RSS values of a Wireless Sensor Network (WSN) to geolocate stationary or moving target(s). The WSN is set up around the Area of Interest (AoI) and the target of interest, which can be a person or object. The target inside the …
Expected Position Error For An Onboard Satellite Gps Receiver, Anthony S. Williams
Expected Position Error For An Onboard Satellite Gps Receiver, Anthony S. Williams
Theses and Dissertations
The Global Positioning System (GPS) constellation provides ranging information that delivers inexpensive, high precision positioning for terrestrial users. Satellites in Low Earth Orbit (LEO) can use an onboard GPS receiver resulting in meter-level navigation solution accuracy. There are limitations to using GPS for positioning for satellites above LEO. The number of GPS satellites who's signal can be received decreases as the receivers altitude approaches that of the GPS constellation. Above the GPS constellation, the available GPS signals for ranging will originate from satellites on the opposite side of Earth. This research calculates the available GPS signals to the receiver and …
Evidence For The Inhibition Of Dengue Virus Binding In The Presence Of Silver Nanoparticles, Kelley J. Williams
Evidence For The Inhibition Of Dengue Virus Binding In The Presence Of Silver Nanoparticles, Kelley J. Williams
Theses and Dissertations
Dengue is an emerging hemorrhagic fever virus and widely considered the most important arbovirus in the world. Dengue virus (DENV) is a positive-sense RNA virus that exists in 4, potentially 5, antigenic serotypes. Currently, no vaccines or treatments are approved for DENV infections. Unsuccessful vaccine trials open the door for non-traditional treatments such as silver nanoparticles. Silver nanoparticles (AgNP) are known to inhibit viral replication of numerous viruses but have never before been tested for inhibition of dengue virus type 2 (DENV2, ATCC® VR-1584TM). For the first time, this research presents up to a 96% reduction in DENV2 …
The Effect Of Stages And Levels Of Automation And Reliability On Workload And Performance For Remotely Piloted Aircraft Operations, Stephen P. Katrein
The Effect Of Stages And Levels Of Automation And Reliability On Workload And Performance For Remotely Piloted Aircraft Operations, Stephen P. Katrein
Theses and Dissertations
This thesis investigates incorporating different stages and levels of automation with varying degrees of reliability into a remotely piloted aircraft (RPA) surveillance task in order to determine how automation implementation and reliability affect operator workload and system performance. The study uses IMPRINT discrete event simulation to evaluate three levels of reliability in twelve different baseline automation implementations within a remotely piloted vehicle task. Three stages and four levels are modeled, for a total of twelve combinations, along with a baseline task with no automation. The stages modeled are the information acquisition stage, the decision and action selection stage, and the …
Error Characterization Of Flight Trajectories Reconstructed Using Structure From Motion, Daniel C. Alix
Error Characterization Of Flight Trajectories Reconstructed Using Structure From Motion, Daniel C. Alix
Theses and Dissertations
This research effort assessed the accuracy of Structure from Motion (SFM) algorithms in replicating aircraft fight trajectories. Structure from Motion techniques can be used to estimate aircraft trajectory by determining the position and pose of an aircraft mounted camera from a sequential series of images taken during flight. An algorithm is proposed and implemented that successfully reconstructed aircraft trajectory using only a known starting position and a sequential series of images. The error in and reliability of the algorithm was found to be a function of image resolution as well as the amount of overlap and angular separation between sequential …
Unique Two-Way Field Probe Concept Utilizing A Geodesic Sphere And Quad-Rotor, Travis A. Albee
Unique Two-Way Field Probe Concept Utilizing A Geodesic Sphere And Quad-Rotor, Travis A. Albee
Theses and Dissertations
Surveying the test volume of a radar range normally involves utilizing an antenna field probe to measure the electromagnetic field in that volume of space. Today, field probes vary in size and shape and can be difficult and time consuming to setup. They also have a limited range of motion due to their support structure and translational mechanism, which also has scattering mechanisms that can perturb the field they are measuring. Field probes are useful, but because of these shortcomings they can provide limited characterization of the field illuminating the measurement area. Leveraging quad-rotor technology, coupled with a two-way probe …
A Novel Analysis Of Performance Classification And Workload Prediction Using Electroencephalography (Eeg) Frequency Data, Donovan L. Ricks
A Novel Analysis Of Performance Classification And Workload Prediction Using Electroencephalography (Eeg) Frequency Data, Donovan L. Ricks
Theses and Dissertations
Across the DOD each task an operator is presented with has some level of difficulty associated with it. This level of difficulty over the course of the task is also known as workload, where the operator is faced with varying levels of workload as he or she attempts to complete the task. The focus of the research presented in this thesis is to determine if those changes in workload can be predicted and to determine if individuals can be classified based on performance in order to prevent an increase in workload that would cause a decline in performance in a …
Robust Models For Operator Workload Estimation, Andrew M. Smith
Robust Models For Operator Workload Estimation, Andrew M. Smith
Theses and Dissertations
When human-machine system operators are overwhelmed, judicious employment of automation can be beneficial. Ideally, a system which can accurately estimate current operator workload can make better choices when to employ automation. Supervised machine learning models can be trained to estimate workload in real time from operator physiological data. Unfortunately, estimating operator workload using trained models is limited: using a model trained in one context can yield poor estimation of workload in another. This research examines the utility of three algorithms (linear regression, regression trees, and Artificial Neural Networks) in terms of cross-application workload prediction. The study is conducted for a …
Single Platform Geolocation Of Radio Frequency Emitters, Eric J. Bailey
Single Platform Geolocation Of Radio Frequency Emitters, Eric J. Bailey
Theses and Dissertations
The focus of this research is on single platform geolocation methods where the position of a single stationary radio frequency emitter is estimated from multiple simulated angle and frequency of arrival measurements taken from a single moving receiver platform. The analysis scenario considered consists of a single 6U CubeSat in low earth orbit receiving radio frequency signals from a stationary emitter located on the surface of the Earth. A multiple element receive antenna array and the multiple signal classification algorithm are used to estimate the angles of arrival of an impinging signal. The maximum likelihood estimator is used to estimate …
Computational Electromagnetic Studies For Low-Frequency Compensation Of The Reflector Impulse-Radiating Antenna, Casey E. Fillmore
Computational Electromagnetic Studies For Low-Frequency Compensation Of The Reflector Impulse-Radiating Antenna, Casey E. Fillmore
Theses and Dissertations
The reflector impulse-radiating antenna (IRA) is considered to meet the requirement for a wideband, directional antenna with short temporal response and small electrical footprint. Standard reflector IRA designs are modeled and performance is simulated using full-wave computational electromagnetic (CEM) software. Characterization of the standard designs reveals the possible existence of wide, frequency-independent backlobes containing nearly 40% of the radiated power at high frequencies. These undesirable backlobes have never been hypothesized, predicted or measured, likely due in part to their alignment outside the primary measurement planes. At the lowest operating frequencies, the reflector IRA is unaffected by backlobes, but is characterized …
Pilot Assisted Inertial Navigation System Aiding Using Bearings-Only Measurements Taken Over Time, Anthony T. Mirabile
Pilot Assisted Inertial Navigation System Aiding Using Bearings-Only Measurements Taken Over Time, Anthony T. Mirabile
Theses and Dissertations
The objective of this work is to develop an alternative INS aiding source other than the GPS, while preserving the autonomy of the integrated navigation system. It is proposed to develop a modernized method of aerial navigation using driftmeter measurements from an E/O system for ground feature tracking, and an independent altitude sensor in conjunction with the INS. The pilot will track a ground feature with the E/O system, while the aircraft is on autopilot holding constant airspeed, altitude, and heading during an INS aiding session. The ground feature measurements from the E/O system and the INS output form measurements …
Effects Of Data Replication On Data Exfiltration In Mobile Ad Hoc Networks Utilizing Reactive Protocols, Corey T. Willinger
Effects Of Data Replication On Data Exfiltration In Mobile Ad Hoc Networks Utilizing Reactive Protocols, Corey T. Willinger
Theses and Dissertations
A swarm of autonomous UAVs can provide a significant amount of ISR data where current UAV assets may not be feasible or practical. As such, the availability of the data the resides in the swarm is a topic that will benefit from further investigation. This thesis examines the impact of le replication and swarm characteristics such as node mobility, swarm size, and churn rate on data availability utilizing reactive protocols. This document examines the most prominent factors affecting the networking of nodes in a MANET. Factors include network routing protocols and peer-to-peer le protocols. It compares and contrasts several open …
The Cognition Of Multiaircraft Control (Mac): Cognitive Ability Predictors, Working Memory, Interference, And Attention Control In Radio Communication, Kelly M. Amaddio
The Cognition Of Multiaircraft Control (Mac): Cognitive Ability Predictors, Working Memory, Interference, And Attention Control In Radio Communication, Kelly M. Amaddio
Theses and Dissertations
As the number of U.S. Air Force missions requiring UAVs has rapidly increased without commensurate increases in manpower, systems which permit a single operator to supervise and control multiple, highly-automated aircraft are being considered. The operator of such a system may be required to monitor and respond to voice communications for multiple UAVs, each of which can have aircraft specific call signs. The need to monitor this array of call signs may impose excessive requirements on constrained operator attention, working memory, and cognitive processing. The current research investigates the cognitive load (number of aircraft call signs) an individual can handle …