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Articles 97921 - 97950 of 198044

Full-Text Articles in Engineering

A Time-Variant Value-Focused Methodology For Supporting Pre-Acquisition, Brian K. Scheller Mar 2016

A Time-Variant Value-Focused Methodology For Supporting Pre-Acquisition, Brian K. Scheller

Theses and Dissertations

Military operations are dynamic in nature, as time-dependent requirements or adversary actions can contribute to differing levels of mission performance among systems. Future military operations commonly use multi-criteria decision analysis techniques that rely on value-focused thinking (VFT) to analyze and ultimately rank alternatives during the Analysis of Alternatives phase of the acquisition process. Traditional VFT approaches are not typically employed with the intention of analyzing time-variant performance of alternatives. In this research, a holistic approach towards integrating fundamental practices such as VFT, systems architecture, and modeling and simulation is used to analyze time-dependent data outputs of an alternative’s performance within …

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Geosynchronous Binary Object Detection, Patrick B. Cunningham Mar 2016

Geosynchronous Binary Object Detection, Patrick B. Cunningham

Theses and Dissertations

This paper will compare competing methods for optically detecting binary objects. This is mostly intended for use in Space Situational Awareness (SSA), though has the potential to be used in other applications. The first method referred to as, “Single Object Detection” is a versatile algorithm which is currently used to detect extraterrestrial objects. However, it does not take into account interference by a nearby object. Therefore a second algorithm is investigated, referred to as “Binary Object Detection”, which does. The binary detection algorithm proved to have a comparable or superior Receiver Operating Characteristic (ROC) curve (based upon the area under …

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Towards Automated Aerial Refueling: Real Time Position Estimation With Stereo Vision, Bradley D. Denby Mar 2016

Towards Automated Aerial Refueling: Real Time Position Estimation With Stereo Vision, Bradley D. Denby

Theses and Dissertations

Aerial refueling is essential to the United States Air Force (USAF) core mission of rapid global mobility. However, in-flight refueling is not available to remotely piloted aircraft (RPA) or unmanned aerial systems (UAS). As reliance on drones for intelligence, surveillance, and reconnaissance (ISR) and other USAF core missions grows, the ability to automate aerial refueling for such systems becomes increasingly critical. New refueling platforms include sensors that could be used to estimate the relative position of an approaching aircraft. Relative position estimation is a key component to solving the automated aerial refueling (AAR) problem. Analysis of data from a one-seventh …

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Airborne Directional Networking: Topology Control Protocol Design, Barry C. Geise Mar 2016

Airborne Directional Networking: Topology Control Protocol Design, Barry C. Geise

Theses and Dissertations

This research identifies and evaluates the impact of several architectural design choices in relation to airborne networking in contested environments related to autonomous topology control. Using simulation, we evaluate topology reconfiguration effectiveness using classical performance metrics for different point-to-point communication architectures. Our attention is focused on the design choices which have the greatest impact on reliability, scalability, and performance. In this work, we discuss the impact of several practical considerations of airborne networking in contested environments related to autonomous topology control modeling. Using simulation, we derive multiple classical performance metrics to evaluate topology reconfiguration effectiveness for different point-to-point communication architecture …

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Dynamic Honeypot Configuration For Programmable Logic Controller Emulation, Kyle A. Girtz Mar 2016

Dynamic Honeypot Configuration For Programmable Logic Controller Emulation, Kyle A. Girtz

Theses and Dissertations

Attacks on industrial control systems and critical infrastructure are on the rise. Important systems and devices like programmable logic controllers are at risk due to outdated technology and ad hoc security measures. To mitigate the threat, honeypots are deployed to gather data on malicious intrusions and exploitation techniques. While virtual honeypots mitigate the unreasonable cost of hardware-replicated honeypots, these systems often suffer from a lack of authenticity due to proprietary hardware and network protocols. In addition, virtual honeynets utilizing a proxy to a live device suffer from performance bottlenecks and limited scalability. This research develops an enhanced, application layer emulator …

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Satellite Ephemeris Correction Via Remote Site Observation For Star Tracker Navigation Performance Improvement, Jorge E. Diaz Mar 2016

Satellite Ephemeris Correction Via Remote Site Observation For Star Tracker Navigation Performance Improvement, Jorge E. Diaz

Theses and Dissertations

In order for celestial navigation observing satellites to provide accurate positioning estimates, precise ephemerides of the observed satellites are necessary. This work analyzed a method to correct for satellite ephemeris to be used in celestial navigation applications. This correction is the measured angle differences between the expected location of the satellite, which is given by propagating publicly available Two-Line Elements (TLE), and their observed angles from a precisely known reference site. Therefore, the angle difference can be attributed completely to satellite ephemeris error assuming instrument error was accounted for. The intent is to calculate this correction from the reference site …

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Using Phase Screens To Synthesize Electromagnetic Gaussian-Schell Model Sources With Desired Amplitude, Coherence, And Polarization, Christopher K. Kokoczka Mar 2016

Using Phase Screens To Synthesize Electromagnetic Gaussian-Schell Model Sources With Desired Amplitude, Coherence, And Polarization, Christopher K. Kokoczka

Theses and Dissertations

An electromagnetic Gaussian-Schell model (EGSM) source is built with desired coherence, amplitude, and polarization using correlated phase screens based on re- search conducted in Refs. [2, 9]. A new method of amplitude control is presented and tested using spatial light modulators (SLM). A brief review of theory and concepts is discussed followed by methods of how to build an EGSM source, correlated phase screens, and control amplitude using SLM gratings. The experimental set-up is presented which builds EGSM sources that demonstrate desired amplitude, coherence, and polarization. Irradiance correlation, degree of polarization, and Stokes parameters S0 and S1 are …

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Characterization Of Quad-Copter Positioning Systems And The Effect Of Pose Uncertainties On Field Probe Measurements, James C. Dossett Mar 2016

Characterization Of Quad-Copter Positioning Systems And The Effect Of Pose Uncertainties On Field Probe Measurements, James C. Dossett

Theses and Dissertations

When measuring the Radar Cross Section (RCS) of a test object, many uncertainties must be accounted for, such as the non-homogeneous nature of the medium between the radar test equipment and the platform under test. There are a variety of other error sources, including clutter and Radio Frequency Interference (RFI), motivating the development of techniques to measure and model the uncertainties in RCS measurements. The following research, in unison with prior and current efforts, intends to reduce the impact of these uncertainties by utilizing a unique two-way field probe in the form of a geodesic sphere encompassing a commercial quad-copter …

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Toward Automated Aerial Refueling: Relative Navigation With Structure From Motion, Kevin W. Colson Mar 2016

Toward Automated Aerial Refueling: Relative Navigation With Structure From Motion, Kevin W. Colson

Theses and Dissertations

The USAF's use of UAS has expanded from reconnaissance to hunter/killer missions. As the UAS mission further expands into aerial combat, better performance and larger payloads will have a negative correlation with range and loiter times. Additionally, the Air Force Future Operating Concept calls for \formations of uninhabited refueling aircraft...[that] enable refueling operations partway inside threat areas." However, a lack of accurate relative positioning information prevents the ability to safely maintain close formation flight and contact between a tanker and a UAS. The inclusion of cutting edge vision systems on present refueling platforms may provide the information necessary to support …

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Real-Time Implementation Of Vision-Aided Monocular Navigation For Small Fixed-Wing Unmanned Aerial Systems, Timothy I. Machin Mar 2016

Real-Time Implementation Of Vision-Aided Monocular Navigation For Small Fixed-Wing Unmanned Aerial Systems, Timothy I. Machin

Theses and Dissertations

The goal of this project was to develop and implement algorithms to demonstrate real-time positioning of a UAV using a monocular camera combined with previously collected orthorectified imagery. Unlike previous tests, this project did not utilize a full inertial navigation system (INS) for attitude, but instead had to rely on the attitude obtained by inexpensive commercial off-the-shelf (COTS) autopilots. The system consisted of primarily COTS components and open-source software, and was own over Camp Atterbury, IN for a sequence of flight tests in Fall 2015. The system obtained valid solutions over much of the flight path, identifying features in the …

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Utilization Of A Geodesic Sphere And Quadcopter As Two-Way Field Probe For Electro-Magnetic Field Measurements In An Indoor Radar Cross Section Range, Nathan Lett Mar 2016

Utilization Of A Geodesic Sphere And Quadcopter As Two-Way Field Probe For Electro-Magnetic Field Measurements In An Indoor Radar Cross Section Range, Nathan Lett

Theses and Dissertations

Radar Cross Section (RCS) measurements rely heavily on multiple assumptions. Uncertainty in the final measurement is determined based on these assumptions. One source in particular is the non-homogeneous nature of the transmission path between radar test equipment and a target under test. The following research extends prior research. This thesis intends to provide a unique two-way field probe solution for measuring Electro-magnetic (EM) fluctuations in a test volume. In this thesis, the design, development, and demonstration of a geodesic sphere encased quadcopter two-way probe is explained. The Parrot® Bebop Drone quadcopter was used with a 2v frequency divided geodesic sphere …

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Non-Linear Optimization Applied To Angle-Of-Arrival Satellite Based Geo-Localization For Biased And Time Drifting Sensors, Daniel E. Levy Mar 2016

Non-Linear Optimization Applied To Angle-Of-Arrival Satellite Based Geo-Localization For Biased And Time Drifting Sensors, Daniel E. Levy

Theses and Dissertations

Multiple sensors are used in a variety of geolocation systems. Many use Time Difference of Arrival (TDOA) or Received Signal Strength (RSS) measurements to locate the most likely location of a signal. When an object does not emit a classical RF signal, Angle of Arrival (AOA) measurements become more feasible than TDOA or RSS measurements. AOA measurements can be created from any sensor platform with any sort of camera. When location and attitude knowledge of the sensor passive objects can be tracked. A Non-Linear Optimization (NLO) method for calculating the most likely estimate from AOA measurements has been created in …

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Comparison Of Methods For Radio Position Of Non-Emitting Dismounts, Collin J. Seanor Mar 2016

Comparison Of Methods For Radio Position Of Non-Emitting Dismounts, Collin J. Seanor

Theses and Dissertations

Radio Tomographic Imaging (RTI) is a form of Device Free Passive Localization (DFPL) that utilizes the Received Signal Strength (RSS) values from a collection of wireless transceivers to produce an image in order to localize a subject within a Wireless Sensor Network (WSN). Radio Mapping is another form of DFPL that can utilize the same RSS values from a WSN to localize a subject by comparing recent values to a set of calibration data. RTI and Radio Mapping have never been directly compared to one another as a means of localization within a WSN. The goal of this research is …

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A Practical Wireless Exploitation Framework For Z-Wave Networks, Joseph L. Hall Mar 2016

A Practical Wireless Exploitation Framework For Z-Wave Networks, Joseph L. Hall

Theses and Dissertations

Wireless Sensor Networks (WSN) are a growing subset of the emerging Internet of Things (IoT). WSNs reduce the cost of deployment over wired alternatives; consequently, use is increasing in home automation, critical infrastructure, smart metering, and security solutions. Few published works evaluate the security of proprietary WSN protocols due to the lack of low-cost and effective research tools. One such protocol is ITU-T G.9959-based Z-Wave, which maintains wide acceptance within the IoT market. This research utilizes an open source toolset, presented herein, called EZ-Wave to identify methods for exploiting Z-Wave devices and networks using Software-Defined Radios (SDR). Herein, techniques enabling …

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Hardware Development And Error Characterisation For The Afit Rail Sar System, Dayne A. Schmidt Mar 2016

Hardware Development And Error Characterisation For The Afit Rail Sar System, Dayne A. Schmidt

Theses and Dissertations

This research is focussed on updating the Air Force Institute of Technology (AFIT) Radar Instrumentation Lab (RAIL) Synthetic Aperture Radar (SAR) experimental system. Firstly, this research assesses current hardware limitations and updates the system configuration and methodology to enable collections from a receiver in motion. Secondly, orthogonal frequency-division multiplexing (OFDM) signals are used to form (SAR) images in multiple experimental and simulation configurations. This research analyses, characterises and attempts compensation of relevant SAR image error sources, such as Doppler shift or motion measurement errors (MMEs). Error characterisation is conducted using theoretical, simulated and experimental methods. Final experimental results are presented …

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Interference Suppression Using Knowledge-Aided Subarray Pattern Synthesis, David A. New Mar 2016

Interference Suppression Using Knowledge-Aided Subarray Pattern Synthesis, David A. New

Theses and Dissertations

Most phased array systems subarray many antenna elements into far fewer digitized channels. While having more degrees of freedom (DOF) yields better performance, adding channels to create more digital DOF increases system cost and data throughput requirements. A subarray itself constitutes a phased array with as many DOF as it has antenna element weights. Typically, only one degree of freedom is used to steer the maximum gain direction of the subarray pattern. For typical antenna geometries a single subarray will provide many more spatial DOF than there are digitized channels. The inherent DOF of the subarrays could be used to …

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Radiation Effects On An Active Ytterbium-Doped Fiber Laser, Adam C. Poulin Mar 2016

Radiation Effects On An Active Ytterbium-Doped Fiber Laser, Adam C. Poulin

Theses and Dissertations

This is the first published research focused on the impact of gamma and mixed gamma/neutron radiation on an actively lasing ytterbium-doped fiber laser. While the gain medium of the ytterbium-doped fiber laser was irradiated, the power was measured in-situ and the spectrum was recorded intermittently. Two radiation sources were used, a 60Co cell and a reactor. Three irradiation experiments were conducted per radiation source; pristine fibers were used for the first two experiments, and fibers from the second experiment were re-irradiated for the third experiment. The results indicate that as the total dose increased linearly with time, the laser …

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Determination Of Fire Control Policies Via Approximate Dynamic Programming, Michael T. Davis Mar 2016

Determination Of Fire Control Policies Via Approximate Dynamic Programming, Michael T. Davis

Theses and Dissertations

Given the ubiquitous nature of both offensive and defensive missile systems, the catastrophe-causing potential they represent, and the limited resources available to countries for missile defense, optimizing the defensive response to a missile attack is a necessary endeavor. For a single salvo of offensive missiles launched at a set of targets, a missile defense system protecting those targets must decide how many interceptors to fire at each incoming missile. Since such missile engagements often involve the firing of more than one attack salvo, we develop a Markov decision process (MDP) model to examine the optimal fire control policy for the …

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Antecedents Of Fuel Efficiency, James A. Cotton Mar 2016

Antecedents Of Fuel Efficiency, James A. Cotton

Theses and Dissertations

Reducing the United States Air Force (USAF)’s fuel use is a major budgetary concern, as the USAF consumes more fuel than the Army, Navy, Marine Corps and all other Department of Defense (DoD) agencies combined. This research focused on fuel efficiency of C-130 Hercules Aircraft Commanders (ACs) by proposing, constructing, and testing a survey measure of behavioral drivers of discretionary pro-environmental professional behaviors among USAF pilots.

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Modeling The Components Of An Economy As A Complex Adaptive System, Richard J. Mickelsen Mar 2016

Modeling The Components Of An Economy As A Complex Adaptive System, Richard J. Mickelsen

Theses and Dissertations

Complex systems science is a relatively new discipline and has not been widely applied to the field of economics. Much of current economic theory relies on principles of constrained optimization and often fails to see economic variables as part of an interconnected network. While tools for forecasting economic indicators are based primarily on autoregressive techniques, these techniques are not always well-suited to predicting the future performance of highly volatile data sets such as the stock market. This research portrays the stock market as one component of a networked system of economic variables, with the federal funds rate acting as an …

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A Model Of Ambient Noise Caused By Wind Flow, Jovan Popovich Mar 2016

A Model Of Ambient Noise Caused By Wind Flow, Jovan Popovich

Theses and Dissertations

The generation of noise caused by wind owing past a human ear is an important yet vastly understudied factor in determining the ambient noise of an environment experienced by a human observer. Sound level measurements were obtained from wind tunnel tests simulating a human experiencing wind ows at various speeds and from various directions. This data set was used in this thesis. This thesis presents a collection of models for predicting wind noise levels across a broad spectrum of frequencies based on wind speed and angle inputs. Graphical approaches are included to characterize the observed data and illustrate the models' …

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Autoencoded Reduced Clusters For Anomaly Detection Enrichment (Arcade) In Hyperspectral Imagery, Brenden A. Mclean Mar 2016

Autoencoded Reduced Clusters For Anomaly Detection Enrichment (Arcade) In Hyperspectral Imagery, Brenden A. Mclean

Theses and Dissertations

Anomaly detection in hyper-spectral imagery is a relatively recent and important research area. The shear amount of data available in a many hyper-spectral images makes the utilization of multivariate statistical methods and artificial neural networks ideal for this analysis. Using HYDICE sensor hyper-spectral images, we examine a variety of preprocessing techniques within a framework that allows for changing parameter settings and varying the methodological order of operations in order to enhance detection of anomalies within image data. By examining a variety of different options, we are able to gain significant insight into what makes anomaly detection viable for these images, …

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Evaluation Of Verification Approaches Applied To A Nonlinear Control System, Kerianne H. Gross Mar 2016

Evaluation Of Verification Approaches Applied To A Nonlinear Control System, Kerianne H. Gross

Theses and Dissertations

As the demand for increasingly complex and autonomous systems grows, designers may consider computational and artificial intelligence methods for more advanced, re- active control. While the performance gained by such increasingly intelligent systems may be superior to traditional control techniques, the lack of transparency in the systems and opportunity for emergent behavior limits their application in the field. New verification and validation methods must be developed to ensure the output of such controllers do not put the system or any people interacting with it in danger. This challenge was highlighted by the former Air Force Chief Scientist in his 2010 …

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Measuring The Effectiveness Of Us Military Humanitarian Construction Projects Through Geospatial Analysis Of Public Opinion In Belize, Arthur Z. Dietrich Mar 2016

Measuring The Effectiveness Of Us Military Humanitarian Construction Projects Through Geospatial Analysis Of Public Opinion In Belize, Arthur Z. Dietrich

Theses and Dissertations

As part of broader US foreign policy efforts the Department of Defense (DoD) increasingly conducts complex operations which focus on efforts to influence local populations. These \hearts and minds" operations often include humanitarian and development construction projects. The wider impact on US foreign policy effort from the US military's participation in projects traditionally conducted by civilian agencies is not well understood. This research examined the effects on local public opinion from two US Air Force led \Operation New Horizons" Humanitarian and Civic Assistance (HCA) missions conducted in the nation of Belize in 2013 and 2014. The study specifically looked for …

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A Simulation-Based Analysis Of Chemical And Radiological Hazard Zones Adapted To Physical Boundaries, Mickie J. Sundheim Mar 2016

A Simulation-Based Analysis Of Chemical And Radiological Hazard Zones Adapted To Physical Boundaries, Mickie J. Sundheim

Theses and Dissertations

In the United States, industrial and terrorist use of chemical, biological, radiological, and nuclear (CBRN) materials pose a risk to public safety. During the initial phase of typical CBRN incidents, emergency responders establish hazard zones based on standard distances from published guidelines and recommendations. This research investigates how standard hazard zones change in a real world environment that accounts for physical boundaries. Using a python simulation in ArcGIS®, new hazard zones were created by expanding standard hazard zones to follow nearby roads, railroads, and rivers. The new and standard zones were compared by calculating the population and area affected by …

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Application Of System Engineering Leading Indicators To Scrum Agile Projects, Eric M. Shirley Mar 2016

Application Of System Engineering Leading Indicators To Scrum Agile Projects, Eric M. Shirley

Theses and Dissertations

SCRUM Agile metrics and System Engineering Leading Indicators (SE LIs) are measures used to evaluate the effectiveness and performance of a project across its lifecycle. The application of metrics can provide information on both internal resources and external project stakeholder requirements and constraints, showing past changes, trends, and potential future impacts. Both SCRUM Agile and SE LIs are designed to give a systems engineer/project manager insight into development progress allowing for progress to be checked at regular intervals as well as early corrective actions to be taken if necessary. This research applied SE LIs to a SCRUM Agile project to …

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Scientometric Analysis Of Technology & Innovation Management Literature, Kadir Yildiz Mar 2016

Scientometric Analysis Of Technology & Innovation Management Literature, Kadir Yildiz

Theses and Dissertations

The management of technology and innovation has become an attractive and promising field within the management discipline. Therefore, much insight can be gained by reviewing the Technology & Innovation Management (TIM) research in leading TIM journals to identify and classify the key TIM issues by meta-categories and to identify the current trends. Based on a comprehensive scientometric analysis of 5,591 articles in 10 leading TIM specialty journals from 2005 to 2014, this research revealed several enlightening findings. First, the United States is the major producer of TIM research literature, and the greatest number of papers was published in Research Policy …

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Optimizing Allocation Of U.S. Humanitarian Civic Assistance Projects In Support Of Developing Foreign Democracy, Christopher E. Wittman Mar 2016

Optimizing Allocation Of U.S. Humanitarian Civic Assistance Projects In Support Of Developing Foreign Democracy, Christopher E. Wittman

Theses and Dissertations

Humanitarian projects in foreign countries are funded by the U.S. government to foster peace, prosperity, and the spread of democratic ideals around the globe. The type and scope of projects are restricted by current doctrine and funding regulations. Specifically in 2014, USAF personnel supported medical and educational construction projects/programs in the country of Belize. Within Belize, medical and educational projects were funded under the Humanitarian and Civic Assistance (HCA) program through the NEW HORIZONS exercise. Fiscal constraints, including shrinking budgets due to sequestration, have placed greater emphasis in the responsible distribution of resources and foreign assistance. The purpose of this …

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Formation Flight Of Earth Satellites On Low-Eccentricity Kam Tori, Christopher T. Craft Mar 2016

Formation Flight Of Earth Satellites On Low-Eccentricity Kam Tori, Christopher T. Craft

Theses and Dissertations

The problem of Earth satellite constellation and formation flight is investigated in the context of Kolmogorov-Arnold-Moser (KAM) theory. KAM tori are constructed utilizing Wiesel’s Low-Eccentricity Earth Satellite Theory, allowing numerical representation of the perturbed tori describing Earth orbits acted upon by geopotential perturbations as sets of Fourier series. A maneuvering strategy using the local linearization of the KAM tangent space is developed and applied, demonstrating the ability to maneuver onto and within desired torus surfaces. Constellation and formation design and maintenance on KAM tori are discussed, along with stability and maneuver error concerns. It is shown that placement of satellites …

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Localized Plasma Measurement During Instability Modes In A Hall Thruster, David A. Cunningham Mar 2016

Localized Plasma Measurement During Instability Modes In A Hall Thruster, David A. Cunningham

Theses and Dissertations

Hall thrusters are a key technology for current and future unmanned satellites, striking a balance between thrust and fuel economy suitable for many mission profiles of interest. Despite their extensive flight heritage and a large body of research, many phenomena occurring in the plasma discharge of Hall thrusters are not well understood. A combination of intrusive and non-intrusive measurement techniques were used to investigate the properties of the exhaust plume of two Hall thrusters and correlate optical characteristics of oscillating modes with the plasma potential and azimuthal current distribution during those modes. A strong trend was found associating the optical …

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