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2015

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Articles 4321 - 4350 of 7527

Full-Text Articles in Engineering

Non-Linear Optimization Applied To Angle-Of-Arrival Satellite-Based Geolocation With Correlated Measurements, Joshua S. Sprang Mar 2015

Non-Linear Optimization Applied To Angle-Of-Arrival Satellite-Based Geolocation With Correlated Measurements, Joshua S. Sprang

Theses and Dissertations

A common remote sensing application is producing geolocation estimates for an object of interest from multiple sensor platforms. Geolocation estimates are desired to help improve situational awareness when dealing with space objects that do not actively broadcast their location. A depiction of the error parameters are calculated in conjunction with the positional estimates. Problems occur when multiple measurements from a single sensor are used to estimate a location due to correlations in sensor error. A non-linear optimization approach is presented for determining geolocation estimates and their associated error parameters. The error parameters directly reflect the error present on the individual …

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On The Integration Of Medium Wave Infrared Cameras For Vision-Based Navigation, Justin S. Tharp Mar 2015

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 …

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Surface Geometry And Chemistry Of Hydrothermally Synthesized Single Crystal Thorium Dioxide, Scott W. Key Mar 2015

Surface Geometry And Chemistry Of Hydrothermally Synthesized Single Crystal Thorium Dioxide, Scott W. Key

Theses and Dissertations

The surface chemistry and geometry of hydrothermally grown, single crystal ThO2 was studied using X-ray Photoemission Spectroscopy (XPS) and Atomic Force Microscopy (AFM). The crystal was studied before and after sputter etching with Ar+, heating up to 675 K, and dehydration with dry nitrogen. The hydrothermal growth technique incorporated Cs and F into the near surface bulk. Heating to 675 K drove off the F, but did not the Cs. Sputtering with Ar+ at 75° cleaned the crystal and created a more uniform surface geometry. The Th 4f peak resolution, as measured by XPS improved by …

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The Effect Of Anisotropic Scatter On Atmospheric Neutron Transport, Nicholas J. Mcintee Mar 2015

The Effect Of Anisotropic Scatter On Atmospheric Neutron Transport, Nicholas J. Mcintee

Theses and Dissertations

Anisotropy is present in the angular distributions of neutrons departing from a nuclear scattering event. This anisotropy cannot be defined in a closed-form solution, and it is dependent on the incident neutron energy, elastic or inelastic scatter, along with the inelastic level, and the species struck. The underlying question is, if anisotropic behavior is worth the computational cost to be included in certain simulations, and if so, what level of precision is effected by the inclusion of anisotropic scatter. A Watt spectrum of U235 fission neutrons was examined as it collided with species in a nitrogen-oxygen atmosphere. In a …

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Overcoming Hurdles Implementing Multi-Skilling Policies, Joshua M. Isom Mar 2015

Overcoming Hurdles Implementing Multi-Skilling Policies, Joshua M. Isom

Theses and Dissertations

Ogden ALC at Hill AFB has been authorized to promote wage grade employees if they are multi-skilled, but that authorization will expire at the end of Fiscal Year 2018. Simulation research by Capt Wesley Sheppard demonstrated significant cost savings/cost avoidance if multi-skilling is pursued, but there are significant challenges to implementation. This research examined two challenges in implementation. First, how many employees can be multi-skilled and still maintain proficiency in both skills? Second, once multi-skilled, is there a technique that can be applied to easily and effectively schedule the new multi-skilled workforce. Using linear programming, staffing numbers were calculated based …

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A Risk Based Approach To Node Insertion Within Social Networks, Chancellor A. J. Johnstone Mar 2015

A Risk Based Approach To Node Insertion Within Social Networks, Chancellor A. J. Johnstone

Theses and Dissertations

Social Network Analysis (SNA) is a primary tool for counter-terrorism operations, ranging from resiliency and influence to interdiction on threats stemming from illicit overt and clandestine network operations. In an ideal world, SNA would provide a perfect course of action to eliminate dangerous situations that terrorist organizations bring. Unfortunately, the covert nature of terrorist networks makes the effects of these techniques unknown and possibly detrimental. To avoid potentially harmful changes to enemy networks, tactical involvement must evolve, beginning with the intelligent use of network in filtration through the application of the node insertion problem. The framework for the node insertion …

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Value Focused Thinking Applications To Supervised Pattern Classification With Extensions To Hyperspectral Anomaly Detection Algorithms, David S. Scanland Mar 2015

Value Focused Thinking Applications To Supervised Pattern Classification With Extensions To Hyperspectral Anomaly Detection Algorithms, David S. Scanland

Theses and Dissertations

Hyperspectral imaging (HSI) is an emerging analytical tool with flexible applications in different target detection and classification environments, including Military Intelligence, environmental conservation, etc. Algorithms are being developed at a rapid rate, solving various related detection problems under certain assumptions. At the core of these algorithms is the concept of supervised pattern classification, which trains an algorithm to data with enough generalizability that it can be applied to multiple instances of data. It is necessary to develop a logical methodology that can weigh responses and provide an output value that can help determine an optimum algorithm. This research focuses on …

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The Cognition Of Multiaircraft Control (Mac): Cognitive Ability Predictors, Working Memory, Interference, And Attention Control In Radio Communication, Kelly M. Amaddio Mar 2015

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 …

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Functionality, Complexity, And Approaches To Assessment Of Resilience Under Constrained Energy And Information, Jason B. Clark Mar 2015

Functionality, Complexity, And Approaches To Assessment Of Resilience Under Constrained Energy And Information, Jason B. Clark

Theses and Dissertations

While system functions, functionality, and complexity are widely used concepts in systems engineering, there is significant diversity in their definitions and no unified approach to measurement. This research establishes a method for measuring impacts to functionality in dynamic engineered systems based on changes in kinetic energy. This metric is applied at particular levels of abstraction and system scales, consistent with the established multiscale nature of systems. By measuring system behavior in context with expected scenarios, it is possible to estimate expected functionality or set bounds on a system's maximum functionality. Functionality and system effectiveness is heavily influenced by the amount …

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Using Earned Value Data To Forecast The Duration Of Department Of Defense (Dod) Space Acquisition Programs, Shedrick M. Bridgeforth Mar 2015

Using Earned Value Data To Forecast The Duration Of Department Of Defense (Dod) Space Acquisition Programs, Shedrick M. Bridgeforth

Theses and Dissertations

The accuracy of cost estimates is vital during this era of budget constraints. A key component of this accuracy is regularly updating the cost estimate at completion (EAC). A 2014 study by the Air Force Cost Analysis Agency (AFCAA) improved the accuracy of the cost estimate at completion (EAC) for space system contracts. The study found schedule duration to be a cost driver, but assumed the underlying duration estimate was accurate. This research attempts to improve the accuracy of the duration estimate from the AFCAA study; accuracy is evaluated with the Mean Absolute Percent Error (MAPE). The methods researched here …

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Modeling, Simulation, And Analysis Of A Decoy State Enabled Quantum Key Distribution System, Ryan D. Engle Mar 2015

Modeling, Simulation, And Analysis Of A Decoy State Enabled Quantum Key Distribution System, Ryan D. Engle

Theses and Dissertations

Quantum Key Distribution (QKD) is an emerging technology which uses the principles of quantum mechanics to provide unconditionally secure key distribution. QKD systems are unique in their ability to detect an eavesdropper's presence and are being marketed for applications where high levels of secrecy are required such as banking, government, and military environments. QKD systems are composed of electrical, optical, and electrooptical components. Their design requires expertise across multiple disciplines including computer science, computer engineering, electrical engineering, information theory, optical physics, and quantum physics. This multidisciplinary nature makes QKD an ideal candidate for study using Model Based Systems Engineering (MBSE) …

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Integrating Pavement Crack Detection And Analysis Using Autonomous Unmanned Aerial Vehicle Imagery, Patrick J. Grandsaert Mar 2015

Integrating Pavement Crack Detection And Analysis Using Autonomous Unmanned Aerial Vehicle Imagery, Patrick J. Grandsaert

Theses and Dissertations

Efficient, reliable data is necessary to make informed decisions on how to best manage aging road assets. This research explores a new method to automate the collection, processing, and analysis of transportation networks using Unmanned Aerial Vehicles and Computer Vision technology. While there are current methodologies to accomplish road assessment manually and semi-autonomously, this research is a proof of concept to obtain the road assessment faster and cheaper with a vision for little to no human interaction required. This research evaluates the strengths of applying UAV technology to pavement assessments and identifies where further work is needed. Furthermore, it validates …

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Analysis Of Air Force Wartime Contracted Construction Project Performance, Ryan M. Hoff Mar 2015

Analysis Of Air Force Wartime Contracted Construction Project Performance, Ryan M. Hoff

Theses and Dissertations

Using a dataset of 25 Afghan wartime projects, two questions were investigated: 1) What factors affect the success of construction projects; and 2) How do project outcomes differ based on the contract type? Current literature suggests that wartime projects may face the same cost and schedule factors as peacetime projects, with some notable additions. Project factors, health and safety compliance, quality of work, technical performance, work productivity, and external environmental factors were tested with contingency tables to determine dependency with schedule or cost performance. External environmental factors, including weather and wartime security, were not predictive of project performance. However, cost …

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The Fate Of Malathion On Copper And Iron Piping Within A Water Distribution System, Walter R. Lee Mar 2015

The Fate Of Malathion On Copper And Iron Piping Within A Water Distribution System, Walter R. Lee

Theses and Dissertations

Thermogravimetry, the study of mass loss as a function of temperature, has been used for oxidation, decomposition, and solid-state studies. This research used a thermogravimetric analyzer (TGA) coupled with Fourier transform infrared (FT-IR) spectroscopy in the study of copper and iron specimens exposed to malathion. Exposure to the malathion solution created a visible silver coating on copper and graphite-flake particles on iron specimens. Thermogravimetric mass loss curves revealed linear and nonlinear decomposition stages associated with mass loss reactions. Copper specimens exposed to malathion exhibited lower activation energy (Ea) values (2.28 to 4.40 kJ mol-1) than for copper specimens exposed to …

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Parametric Estimation Of Load For Air Force Datacenters, Derek P. Molle Mar 2015

Parametric Estimation Of Load For Air Force Datacenters, Derek P. Molle

Theses and Dissertations

The Office of Management and Budget (OMB) has tasked Federal agencies to develop a Data Center Consolidation Plan. Effective planning requires a repeatable method to effectively and efficiently size Air Force Base-level data centers. Review of commercial literature on data center design found emphasis in power efficiency, thermal modeling and cooling, and network speed and availability. The topic of sizing data center processing capacity seems undeveloped. This thesis provides a better, pedigreed solution to the data center sizing problem. By analogy, Erlang's formulae for the probability of blocking and queuing should be applicable to cumulative CPU utilization in a data …

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A Comparative Study Of Learning Curve Models In Defense Airframe Cost Estimating, Justin R. Moore Mar 2015

A Comparative Study Of Learning Curve Models In Defense Airframe Cost Estimating, Justin R. Moore

Theses and Dissertations

The goal of this research was to identify which learning curve model is most accurate when applied to Defense acquisition programs. Wright's original learning curve model is widely accepted and used within Defense acquisitions, but the 75+ year old model may be outdated. This study compares Wright's model against three alternative learning curve models using total lot costs for the F-15 C/D & E programs: the Stanford-B model, the DeJong learning formula, and the S-Curve model. However, the results of the study are inconclusive. Two of the three alternative models, the DeJong and S-Curve, rely on the use of an …

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Pulsed Ultraviolet Light Emitting Diodes For Advanced Oxidation Of Tartrazine, Patrick M. Mudimbi Mar 2015

Pulsed Ultraviolet Light Emitting Diodes For Advanced Oxidation Of Tartrazine, Patrick M. Mudimbi

Theses and Dissertations

A study was conducted to evaluate the advanced oxidation of organic contaminants using pulsed ultraviolet light emitted diode (UV LED). Tartrazine was used as a surrogate organic compound. Low pressure Mercury-based lamps currently used in the treatment of water pose potential health risks if broken and create final disposal issues at the end of their service life. UV LED offers an alternative solution due to its non-toxicity, flexible design, and longer operating life compared to the mercury-based lamps. The apparent first order reaction rate constant for tartrazine degradation increased linearly with increasing duty cycle. At a continuous 100% duty cycle, …

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Pragmatic Divestment Of Kc-135 Navigators In The Special Operations Air Refueling Mission, Andrew P. Nation Mar 2015

Pragmatic Divestment Of Kc-135 Navigators In The Special Operations Air Refueling Mission, Andrew P. Nation

Theses and Dissertations

In the late 1990s, the Air Force eliminated over 200 KC-135 navigators, leaving 50 remaining for the aircraft's most complex Special Operations Air Refueling (SOAR) mission. As the Air Force unveils the KC-46 Pegasus, this mission will continue but without a position for the navigator. Instead, navigators will undergo divestment as the SOAR mission transfers to the KC-46. Current plans indicate navigators will not only remain as the KC-46 arrives, but inbound navigators will continue arriving until 2018. This thesis applies the Delphi method, a process eliciting analysis anonymously from a panel of experts, in order to examine the elements …

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The Effect Of Malathion On The Activity And Performance Of Activated Sludge, Erik G. Rauglas Mar 2015

The Effect Of Malathion On The Activity And Performance Of Activated Sludge, Erik G. Rauglas

Theses and Dissertations

Decontamination activities following a chemical weapons incident may generate significant quantities of contaminated wash water that may enter the wastewater collection system either intentionally or accidentally. This raises concerns about the effect of chemical warfare agents (CWAs) on the operation of a biological wastewater treatment plant. The goal of the study was to evaluate the effect of malathion on the activity and performance of activated sludge. Malathion is an organophosphate (OP) and is considered an environmental surrogate for VX. This study employed respirometry, short term batch tests, and long term exposure experiments to investigate the effects of different concentrations of …

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Low Earth Orbit Satellite Tracking Telescope Network: Collaborative Optical Tracking For Enhanced Space Situational Awareness, Victor A. Salvador Mar 2015

Low Earth Orbit Satellite Tracking Telescope Network: Collaborative Optical Tracking For Enhanced Space Situational Awareness, Victor A. Salvador

Theses and Dissertations

The Air Force Institute of Technology has spent the last seven years conducting research on orbit identification and object characterization of space objects through the use of commercial-off-the-shelf hardware systems controlled via custom software routines, referred to simply as TeleTrak. Year after year, depending on the research objectives, students have added or modified the system's hardware and software to achieve their individual research objectives. In the last year, due to operating system and software upgrades, TeleTrak became inoperable. Furthermore, due to a lack of student overlap, knowledge of the basic operation of the TeleTrak deteriorated. This research re-establishes the basic …

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Army Information Technology Procurement: A Business Process Analysis, Alexander M. Vukcevic Mar 2015

Army Information Technology Procurement: A Business Process Analysis, Alexander M. Vukcevic

Theses and Dissertations

This thesis presents a business process analysis of the Army's ICT procurement system. The research identified several inefficiencies and proposes several potential solutions. the contributions of this research include a unified taxonomy, a method to prioritize requests, and system architecture products for development of an automated and sustainable collaboration interface for the CIO/G6 to streamline their IT acquisition process. Development of a centralized system would reduce waste in the request process from submission to formal accounting, hasten the movement of requests between stakeholders, maintain a digital signature authorization for each approval authority, provide a reporting database to recognize reprogramming thresholds, …

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Error Characterization Of Flight Trajectories Reconstructed Using Structure From Motion, Daniel C. Alix Mar 2015

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 …

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Impacts Of Severe Weather, Climate Zone, And Energy Factors On Base Realignment And Closure (Brac), Christopher L. Teke Mar 2015

Impacts Of Severe Weather, Climate Zone, And Energy Factors On Base Realignment And Closure (Brac), Christopher L. Teke

Theses and Dissertations

The Air Force is in a period of downsizing, both aircraft and personnel. In recent years, the service has cut hundreds of aircraft from its fleet and decreased military end-strength, but has not substantially reduced its infrastructure. Consequently, the cost to operate and maintain Air Force Bases is not decreasing. Mitigation methods are needed to manage the costly burden of excess infrastructure. A new Base Realignment and Closure (BRAC) round will help the Air Force reduce unnecessary infrastructure and alleviate precious resources necessary for weapon modernization and improved readiness. Cost savings through BRAC can help the Air Force achieve reduced …

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Methods Of Measuring Stress Relaxation In Composite Tape Springs, Justin T. Heppe Mar 2015

Methods Of Measuring Stress Relaxation In Composite Tape Springs, Justin T. Heppe

Theses and Dissertations

Composite tape springs present an opportunity to use stored energy for the deployment of space structures. Concern has risen over the dissipation of strain energy during storage due to viscoelasticity inherent in polymeric materials commonly used as the composite matrix. Tests to measure the internal behavior of a composite tape spring over time are conducted along with methods of analyzing and fitting the resulting data. The three constant strain configurations tested were compression force of the cross section, a restraining force of a longitudinal fold, and the change in shape of a folded section. While the shape changing test did …

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Navigation Constellation Design Using A Multi-Objective Genetic Algorithm, Heather C. Diniz Mar 2015

Navigation Constellation Design Using A Multi-Objective Genetic Algorithm, Heather C. Diniz

Theses and Dissertations

In satellite constellation design, performance and cost of the system drive the design process. The Global Positioning System (GPS) constellation is currently used to provide positioning and timing worldwide. As satellite technology has improved over the years, the cost to develop and maintain the satellites has increased. Using a constellation design tool, it is possible to analyze the tradeoffs of new navigation constellation designs (Pareto fronts) that illustrate the tradeoffs between position dilution of precision (PDOP) and system cost. This thesis utilized Satellite Tool Kit (STK) to calculate PDOP values of navigation constellations, and the Unmanned Spacecraft Cost Model (USCM) …

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Dynamic Response Analysis Of An Icosahedron Shaped Lighter Than Air Vehicle, Lucas W. Just Mar 2015

Dynamic Response Analysis Of An Icosahedron Shaped Lighter Than Air Vehicle, Lucas W. Just

Theses and Dissertations

The creation of a lighter than air vehicle using an inner vacuum instead of a lifting gas is considered. Specifically, the icosahedron shape is investigated as a design that will enable the structure to achieve positive buoyancy while resisting collapse from the atmospheric pressure applied. This research analyzes the dynamic response characteristics of the design, and examines the accuracy of the finite element model used in previous research by conducting experimental testing. The techniques incorporated in the finite element model are confirmed based on the experimental results using a modal analysis. The experimental setup designed will allow future research on …

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Optimized Flight Path For Localization Using Line Of Bearing, Namkyu Kim Mar 2015

Optimized Flight Path For Localization Using Line Of Bearing, Namkyu Kim

Theses and Dissertations

This research develops optimized flight paths for localization of a target using LOB measurements. The target area is expressed as an error ellipse using the measurement errors of the LOBs. The optimization approach is focused on minimizing the size of the error ellipse. The algorithm for the optimized path is generated and compared with typical flight paths. The optimization routine is based on the results revised from previous similar research in the literature. A geometrical method to estimate the error ellipse is combined with optimal control in this research. Each LOB gives a possible target area and this target area …

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Reflections Of A Wave: An Analysis Of Photonic Doppler Velocimetry Systems, Brian K. Lagrange Mar 2015

Reflections Of A Wave: An Analysis Of Photonic Doppler Velocimetry Systems, Brian K. Lagrange

Theses and Dissertations

Munitions are one of the Air Force's most effective weapons in eliminating targets, but also one of the most expensive. Due to the inherent high-cost in deploying munitions, munition shock wave detonation must be better observed and quantified for munitions to be more cost-efficient. PDV systems have the potential to achieve this quantification of shock wave properties on a molecular scale during solid-against-solid impacts. The overall goal of this research was to determine whether the current photonic Doppler velocimetry (PDV) system at Eglin Air Force Base is prepared for future explosive sensitivity testing. This determination was done through an uncertainty …

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A Monocular Slam Method To Estimate Relative Pose During Satellite Proximity Operations, Scott J. Kelly Mar 2015

A Monocular Slam Method To Estimate Relative Pose During Satellite Proximity Operations, Scott J. Kelly

Theses and Dissertations

Automated satellite proximity operations is an increasingly relevant area of mission operations for the US Air Force with potential to significantly enhance space situational awareness (SSA). Simultaneous localization and mapping (SLAM) is a computer vision method of constructing and updating a 3D map while keeping track of the location and orientation of the imaging agent inside the map. The main objective of this research effort is to design a monocular SLAM method customized for the space environment. The method developed in this research will be implemented in an indoor proximity operations simulation laboratory. A run-time analysis is performed, showing near …

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A Cubesat Mission For Mapping Spot Beams Of Geostationary Communications Satellites, Jacob A. Lasarge Mar 2015

A Cubesat Mission For Mapping Spot Beams Of Geostationary Communications Satellites, Jacob A. Lasarge

Theses and Dissertations

As space-rated technologies become more compact and more readily available over time, the concept of accomplishing space missions with smaller nanosatellite-class spacecraft becomes increasingly feasible. This research focuses specifically on a CubeSat mission to assist with radio frequency (RF) domain verification; that of characterizing and mapping K-band spot beams from communications satellites in geostationary orbit. By flying a constellation of CubeSats through the edges of spot beams originating from geostationary communication satellites, the spot beam's coverage area will be characterized. This research conducts a mission feasibility assessment, identifies the principle mission requirements to complete a spot beam mapping CubeSat mission, …

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