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Systems Engineering and Multidisciplinary Design Optimization Commons™
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Articles 31 - 60 of 84
Full-Text Articles in Systems Engineering and Multidisciplinary Design Optimization
Utilizing Supercomputing To Analyze Risks Of An Emergent Large-Scale Debris Field In Low Earth Orbit, David J. Buehler
Utilizing Supercomputing To Analyze Risks Of An Emergent Large-Scale Debris Field In Low Earth Orbit, David J. Buehler
Theses and Dissertations
The likelihood of on-orbit breakups, whether spontaneous or the result of collision, will likely continue to grow as the barriers of entry to and use of space are reduced. In all orbital regimes, especially low Earth orbit (LEO), preparation to respond quickly when the next breakup occurs is critical. This research utilizes high-performance parallel computation along with python-driven Systems Tool Kit (STK) to model a large-scale on-orbit breakup in LEO, with the goal of returning data in less than 90 minutes. The breakup is characterized by the National Aeronautics and Space Administration (NASA) EVOLVE 4.0 breakup model and is both …
Optimal Configurations For Aerosol Monitoring With Multi-Rotor Small Unmanned Aerial Systems, Inna D. Chavez
Optimal Configurations For Aerosol Monitoring With Multi-Rotor Small Unmanned Aerial Systems, Inna D. Chavez
Theses and Dissertations
Applicability of aerosol sampling on multi-rotor unmanned aerial systems (UAS) platform was investigated. Multi-rotor UAS have impacts of wind speed, turbulence, and orientation possibly contributing to sampling bias. The SKC IMPACT sampler, Tecora C.A.Th.I.A., and modified three-dimensionally printed Universal Inlet for Airborne-Particle Size-Selective Sampling were selected based on particle size-selectivity and operational independence to wind. Airflow visualizations concluded that below UAS fuselage was optimal sampler placement. Tests were conducted with Arizona Road Dust in a still-air chamber, and aerosolized sugar in a wind tunnel. Inlet mounting was evaluated in, upright, upside-down, and horizontal orientations. Horizontal orientations of all inlets resulted …
Optimal Design Of A Hexakis Icosahedron Vacuum Based Lighter Than Air Vehicle, Joseph R. Schwemmer
Optimal Design Of A Hexakis Icosahedron Vacuum Based Lighter Than Air Vehicle, Joseph R. Schwemmer
Theses and Dissertations
Due to the rising cost and scarcity of helium, new methods to ensure buoyancy for lighter-than-air vehicles (LTAVs) are being sought. One alternative under study uses an internal vacuum to reduce the weight to buoyancy ratio. It's a novel approach; however, the vacuum presents challenges for the vehicle's structure. The structure must have minimum mass while preventing buckling and excess stress throughout the frame and membrane. The structure under analysis is a hexakis icosahedron with a membrane covering. Achieving minimum mass involves optimizing the structure under the loading conditions. Finite-element analysis (FEA) and direct-search methods are employed, providing an optimal …
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 Methodology For The Optimization Of Disaggregated Space System Conceptual Designs, Robert E. Thompson
A Methodology For The Optimization Of Disaggregated Space System Conceptual Designs, Robert E. Thompson
Theses and Dissertations
Optimal design techniques have proven to be an effective systems engineering tool. Using systems architecture as the foundation, this research explores the use of mixed variable optimization models for synthesizing and evaluating disaggregated space system concepts. Model-based conceptual design techniques are used to identify and assess system architectures based upon estimated system cost, performance trades, and cost risk. The Disaggregated Integral System Concept Optimization (DISCO) methodology is introduced, and then applied to representative space-based missions. Several results are obtained that indicate significant cost effectiveness gains from the optimization of multi-orbit and multi-function/multi-orbit disaggregated space systems. The general methodology has broad …
Improving The Performance Of The Space Surveillance Telescope As A Function Of Seeing Parameter, Jae H. Jeon
Improving The Performance Of The Space Surveillance Telescope As A Function Of Seeing Parameter, Jae H. Jeon
Theses and Dissertations
This research paper investigates ways to improve the detection capability and predict the performance of the Space Surveillance Telescope (SST) system when it's relocated to Exmouth, Australia. The dataset collected by the SST observing the Geosynchronous Earth Orbit (GEO) satellite, ANIK-F1, entering the earth's eclipse is used to test the performance of the three existing and one new detection algorithm. The three existing algorithms are the point detection (Binary Hypothesis Test (BHT)), correlation detection (CD-BHT), and Multi-hypothesis Test using ten hypotheses (MHT10), and the new detection algorithm is the Multi-hypothesis Test using six hypotheses (MHT6). To improve the accuracy and …
Multi-Objective Trajectory Optimization Of A Hypersonic Reconnaissance Vehicle With Temperature Constraints, Tadeusz J. Masternak
Multi-Objective Trajectory Optimization Of A Hypersonic Reconnaissance Vehicle With Temperature Constraints, Tadeusz J. Masternak
Theses and Dissertations
Temperature-constrained optimal trajectories for a scramjet-based hypersonic reconnaissance vehicle were generated by developing an optimal control formulation and solving it using a variable order Gauss-Radau quadrature collocation method. The vehicle was assumed to be an air-breathing reconnaissance aircraft that has specified takeoff/landing locations, airborne refueling constraints, specified no-fly zones, and specified targets for sensor data collections. The aircraft model included fight dynamics, aerodynamics, and thermal constraints. This model was incorporated into an optimal control formulation that includes constraints on both the vehicle as well as mission parameters, such as avoidance of no-fly zones and coverage of high-value targets. Optimal trajectories …
Feasibilty Of Very Large Sparse Aperture Depolyable Antennas, Jason C. Heller
Feasibilty Of Very Large Sparse Aperture Depolyable Antennas, Jason C. Heller
Theses and Dissertations
The objective of this research is to explore the technical soundness of a very large, cross-shaped, parabolic, sparse aperture antenna extending 75 m from the bus. Specifically, describing the environment of the satellite, the effect of fabrication error on the structure and the remaining error budget for the system. The methodology involves creation of an ideal truss structure, to which all others are compared. A uniform distribution of proportional errors up to 1e-5 is introduced into the truss members' lengths and the models are subjected to a static Finite Element Analysis. A solution for the surface normal error is addressed …
Architecting Integrated System Health Management For Airworthiness, Kerwin C. Teong
Architecting Integrated System Health Management For Airworthiness, Kerwin C. Teong
Theses and Dissertations
Integrated System Health Management (ISHM) for Unmanned Aerial Systems (UAS) has been a new area of research - seeking to provide situational awareness to mission and maintenance operations, and for improved decision-making with increased self-autonomy. This research effort developed an analytic architecture and an associated discrete-event simulation using Arena® to investigate the potential benefits of ISHM implementation onboard an UAS. The objective of this research is two-fold: firstly, to achieve continued airworthiness by investigating the potential extension of UAS expected lifetime through ISHM implementation, and secondly, to reduce life cycle costs by implementing a Condition-Based Maintenance (CBM) policy with better …
Pseudolite Architecture And Performance Analysis For The Faa's Nextgen Airspace, Joseph A . Czabaranek
Pseudolite Architecture And Performance Analysis For The Faa's Nextgen Airspace, Joseph A . Czabaranek
Theses and Dissertations
By 2025 the FAA plans to have fully implemented its NextGen Airspace design. NextGen takes advantage of modern positioning technologies as well as automation, data sharing, and display technologies that will allow more efficient use of our ever busier National Airspace (NAS). A key element of NextGen is the transition from surveillance RADAR providing aircraft separation and navigation to the use of the GPS and Automatic Dependent Surveillance Broadcast (ADS-B). ADS-B couples the precision of the GPS with networked ground and airborne receivers to provide precise situational awareness to pilots and controllers. The result is increased safety, capacity, and access …
Supplementary Computer Generated Cueing To Enhance Air Traffic Controller Efficiency, Laurienne Cibelle Rodrigues De Assis Santana
Supplementary Computer Generated Cueing To Enhance Air Traffic Controller Efficiency, Laurienne Cibelle Rodrigues De Assis Santana
Theses and Dissertations
Air traffic controllers are often required to simultaneously communicate with several aircraft over multiple radio frequencies. As a result, during peak loading, it is common for the controller to receive multiple concurrent communications, each from a different aircraft, making it difficult to discern audio messages received from multiple pilots simultaneously. To address this problem, a modified air traffic control (ATC) interface was prototyped with the goal of increasing controller-to-pilot communication efficiency. This prototype included supplementary text cueing which was provided by a hypothetical automated text to speech system in an on-screen text box for controller reference in the event of …
Development Of Autonomous Optimal Cooperative Control In Relay Rover Configured Small Unmanned Aerial Systems, Timothy J. Shuck
Development Of Autonomous Optimal Cooperative Control In Relay Rover Configured Small Unmanned Aerial Systems, Timothy J. Shuck
Theses and Dissertations
This thesis documents the research effort to develop, integrate and implement the system hardware and the software necessary to validate the Air Force Institute of Technology's theoretical advances in small unmanned aerial systems (SUAS) cooperative control. The end state objective of the research effort was to flight test an autonomous control algorithm on a communication relay unmanned aerial vehicle (UAV) that was actively relaying data to and from a rover UAV. The relay UAV is one part of a SUAS designed to utilize cooperative control to extend the effective line-of-sight operating range for a rover UAV. An algorithm is integrated …
Effects Of Stereoscopic 3d Digital Radar Displays On Air Traffic Controller Performance, Jason G. Russi
Effects Of Stereoscopic 3d Digital Radar Displays On Air Traffic Controller Performance, Jason G. Russi
Theses and Dissertations
Air traffic controllers are responsible for directing air traffic based upon decisions made from traffic activity depicted on 2Dimensional (2D) radar displays. Controllers must identify aircraft and detect potential conflicts while simultaneously developing and executing plans of action to ensure safe separation is maintained. With a nearly 100% increase in traffic expected within the next decade (FAA, 2012a), controllers' abilities to rapidly interpret spacing and maintain awareness for longer durations with increased workload will become increasingly imperative to safety. The current display design spatially depicts an aircraft's position relative to the controller's airspace as well as speed, altitude, and direction …
Aircraft Course Optimization Tool Using Gpops Matlab Code, Ryan D. Gauntt
Aircraft Course Optimization Tool Using Gpops Matlab Code, Ryan D. Gauntt
Theses and Dissertations
Aircraft course planning between two points in a clear, no threat environment is easy and straightforward. However, the addition of various threats can greatly increase the difficulty and complexity of course planning. Placing new waypoints along the edge of each threat, mostly skirting the dangerous environment, may not prove too difficult, but such courses are far from optimal. Given aircraft, environment, and time constraints it is likely a much more optimal path exists between any given start and end points. This research focuses on determining the feasibility of using the General Pseudospectral Optimization Software program files written for the MATLAB …
Link Performance Analysis For A Proposed Future Architecture Of The Air Force Satellite Control Network, Eric W. Nelson
Link Performance Analysis For A Proposed Future Architecture Of The Air Force Satellite Control Network, Eric W. Nelson
Theses and Dissertations
The Air Force Satellite Control Network (AFSCN) is a worldwide network of ground stations that support a wide variety of users from the National Aeronautics and Space Administration (NASA) to the National Reconnaissance Office (NRO). The network performs tracking, telemetry, and commanding (TT&C) for these varied users. Users, located at Satellite Operations Centers (SOC), must compete for time on the AFSCN. This thesis demonstrates how to predict satellite link performance, specifically by users of the AFSCN. It will also demonstrate how users might use this capability to save spacecraft power. A tool was created called the AFSCN Link Predictor (LP) …
Solar Warning Architecture For Manned Missions To Mars, James S. Bohren, John K. Howard
Solar Warning Architecture For Manned Missions To Mars, James S. Bohren, John K. Howard
Theses and Dissertations
Solar radiation storms represent a dire threat to manned interplanetary space travel. Earth's current solar forecasting architecture is Earth-focused and insufficient to provide timely warnings to a manned mission to Mars, therefore a "best value" solar warning architecture must be identified. A total of 14 solar warning architectures were developed by varying 5 solar sensor locations, 2 processing locations, and 2 communications strategies. Using Satellite Tool Kit, performance of the candidate architectures in terms of Warning Time and Solar Coverage was quantified during a Mars mission scenario based on NASA's Design Reference Architecture 5.0. Cost of each candidate architecture was …
Architecture Based Workload Analysis Of Uas Multi-Aircraft Control: Implications Of Implementation On Mq-1b Predator, Jason D. Mcgrogan, Michael F. Schneider
Architecture Based Workload Analysis Of Uas Multi-Aircraft Control: Implications Of Implementation On Mq-1b Predator, Jason D. Mcgrogan, Michael F. Schneider
Theses and Dissertations
An increased demand for use of Unmanned Aircraft Systems (UASs) without commensurate increases in pilot manpower has prompted proposals for simultaneous control of multiple aircraft by a single pilot or Multi-Aircraft Control (MAC). To understand the potential effects of MAC, an IMPRINT Pro, Multi-Resource Theory, pilot workload model was developed from pedigreed system architecture. Feedback from active UAS pilots was used to validate the model and establish a workload saturation threshold value of 60, above which pilots may experience performance degradation over extended periods of time. The model predicts that pilots experience low workload when operating one or two UASs …
Satellite Capabilities Mapping - Utilizing Small Satellites, David A. Grigsby
Satellite Capabilities Mapping - Utilizing Small Satellites, David A. Grigsby
Theses and Dissertations
The cost and schedule advantages small satellites have over larger legacy systems have been studied, but there has been very little experimentation performed to determine whether small satellites can actually deliver the capabilities of larger spacecraft. To date, a desired operational capability has not been fully realized by a scalable satellite design. Advances in sensor technology have led to significant reductions in size, weight, and power (SWaP) presenting an opportunity to exploit the evolution of space operations by using small satellites to perform specific missions. This paper describes a methodology that maps a specific set of large space vehicle capabilities …
Simulation And Application Of Gpops For Trajectory Optimization And Mission Planning Tool, Danielle E. Yaple
Simulation And Application Of Gpops For Trajectory Optimization And Mission Planning Tool, Danielle E. Yaple
Theses and Dissertations
Rapid trajectory generation is crucial to prompt global warfare. To meet the USAF’s objective of Persistent and Responsive Precision Engagement, a rapid mission planning tool is required. This research creates the framework for the mission planning tool and provides a sample optimal trajectory which is solved using the GPOPS software package. GPOPS employs a Gaussian pseudospectral method to solve the non-linear equations of motion with both end conditions and path constraints. By simultaneously solving the entire trajectory based on an initial guess and small number of nodes, this method is ideal for generating rapid solutions. The sample case is a …
Cooperative Unmanned Aerial Surveillance Control System Architecture, Theodore T. Diamond, Adam L. Rutherford, Jonathan B. Taylor
Cooperative Unmanned Aerial Surveillance Control System Architecture, Theodore T. Diamond, Adam L. Rutherford, Jonathan B. Taylor
Theses and Dissertations
Intelligence, surveillance and reconnaissance (ISR) is a high-demand Department of Defense mission performed by unmanned aircraft systems (UASs) at the tactical and theater levels. Coordinating UASs through cooperative control offers the advantages of persistence, distributed and adaptable sensor coverage, and reduced revisit time on points of interest. The purpose of this thesis is to apply systems engineering principles to the problem of developing a flexible, common control system for cooperative UAS surveillance at the tactical level. The AFIT team developed a concept of operations (CONOPS) encompassing various users and surveillance tasks. The team then used the scenarios in the CONOPS …
Architecting Human Operator Trust In Automation To Improve System Effectiveness In Multiple Unmanned Aerial Vehicles (Uav), Eric A. Cring, Adam G. Lenfestey
Architecting Human Operator Trust In Automation To Improve System Effectiveness In Multiple Unmanned Aerial Vehicles (Uav), Eric A. Cring, Adam G. Lenfestey
Theses and Dissertations
Current Unmanned Aerial System (UAS) designs require multiple operators for each vehicle, partly due to imperfect automation matched with the complex operational environment. This study examines the effectiveness of future UAS automation by explicitly addressing the human/machine trust relationship during system architecting. A pedigreed engineering model of trust between human and machine was developed and applied to a laboratory-developed micro-UAS for Special Operations. This unprecedented investigation answered three primary questions. Can previous research be used to create a useful trust model for systems engineering? How can trust be considered explicitly within the DoD Architecture Framework? Can the utility of architecting …
Tools For The Conceptual Design And Engineering Analysis Of Micro Air Vehicles, Mustafa Turan
Tools For The Conceptual Design And Engineering Analysis Of Micro Air Vehicles, Mustafa Turan
Theses and Dissertations
Micro Air Vehicles (MAV) are a subset of Unmanned Aircraft (UAS) that are up to two orders of magnitude smaller than manned systems. Near-Earth environments, such as forests, caves, tunnels and urban structures make reconnaissance, surveillance and search-and-rescue missions difficult and dangerous to accomplish. Therefore, MAVs are considered ideal for these types of missions. However, the data using full size aircraft is inadequate to characterize miniature aircraft parameters due to the lower Reynolds numbers and low aspect ratio (LAR) wings and impact of wing-propeller interactions. The main objectives of this research were to: collect and synthesize the available data/tools; create …
Optimal Guidance Of A Relay Mav For Isr Support Beyond Line-Of-Sight, John H. Hansen
Optimal Guidance Of A Relay Mav For Isr Support Beyond Line-Of-Sight, John H. Hansen
Theses and Dissertations
This thesis developed guidance laws to optimally position a relay Micro-UAV (MAV) to provide an operator with real-time Intelligence, Surveillance, and Reconnaissance (ISR) by relaying communication and video signals when there is no line-of-sight between the operator at the base and the rover MAV performing the ISR mission. The ISR system consists of two MAVs, the Relay and the Rover, and a Base. The Relay strives to position itself to minimize the radio frequency (RF) power required for maintaining communications between the Rover and the Base, while the Rover performs the ISR mission, which may maximize the required RF power. …
Investigation Into Nanocomposites For Applications In Lightning Strike Protection, Matthew S. Bond, James A. Rodriguez, Hieut T. Nguyen
Investigation Into Nanocomposites For Applications In Lightning Strike Protection, Matthew S. Bond, James A. Rodriguez, Hieut T. Nguyen
Theses and Dissertations
The United States Air Force is continually researching ways to reduce costs associated with aircraft maintenance and improve operational safety. This study focuses on creating a systems engineering process to develop an Integrated Structural Health Monitoring System (ISHMS). The overarching process was then applied to design a conceptual ISHMS for a real-world scenario involving the F-15. Sensor selection, integration and testing were explored in detail using frequency response methods to detect structural damage. Testing was accomplished using a simplified structural specimen with Monitoring & Evaluation Technology Integration System (METIS) disk nodes attached at various locations. Two different METIS disk operation …
Determining Logistics Ground Support Manpower Requirements For A Reusable Military Launch Vehicle, Sydney C. Michalski
Determining Logistics Ground Support Manpower Requirements For A Reusable Military Launch Vehicle, Sydney C. Michalski
Theses and Dissertations
Successful space-based technologies like satellite imagery and GPS have increased military demand for a rapid-response launch capability. AF Space Command's Operationally Responsive Spacelift program was developed to ensure that the AF has the capability to launch a payload into orbit within hours of a tasking notification, and requires development of a new space launch vehicle. The Reusable Military Launch Vehicle (RMLV) is currently in the design phase. The AF Research Laboratory sponsored development of the MILEPOST simulation model in order to assess the turnaround time, and thus responsiveness, of various design alternatives. The focus of this thesis is to improve …
Prioritizing Satellite Payload Selection Via Optimization, Benjamin S. Kallemyn
Prioritizing Satellite Payload Selection Via Optimization, Benjamin S. Kallemyn
Theses and Dissertations
This thesis develops optimization models for prioritizing payloads for inclusion on satellite buses with volume, power, weight and budget constraints. The first model considers a single satellite launch for which the budget is uncertain and constellation requirements are not considered. Subsequently, we include constellation requirements and provide a more enhanced model. Both single-launch models provide a prioritized list of payloads to include on the launch before the budget is realized. The single-launch models are subsequently extended to a sequence of multiple launches in two cases, both of which incorporate an explicit dependence on the constellation composition at each launch epoch. …
A Comparative Analysis Of Transmission Control Protocol Improvement Techniques Over Space-Based Transmission Media, Joseph M. Lawson
A Comparative Analysis Of Transmission Control Protocol Improvement Techniques Over Space-Based Transmission Media, Joseph M. Lawson
Theses and Dissertations
The purpose of this study was to assess the throughput improvement afforded by the various TCP optimization techniques, with respect to a simulated geosynchronous satellite system, to provide a cost justification for the implementation of a given enhancement technique. The research questions were answered through model and simulation of a satellite transmission system via a Linux-based network topology; results of the simulation were analyzed primarily via a non-parametric method to ascertain performance differences between the various TCP optimization techniques. It was determined that each technique studied, which included the Space Communication Protocol Standard-Transport Protocol (SCPS-TP), window scale, selective acknowledgements (SACKs), …
Development Of Autonomous Unmanned Aerial Vehicle Platform: Modeling, Simulating, And Flight Testing, Nidal M. Jodeh
Development Of Autonomous Unmanned Aerial Vehicle Platform: Modeling, Simulating, And Flight Testing, Nidal M. Jodeh
Theses and Dissertations
The Advanced Navigation Technology (ANT) Center at the Air Force Institute of Technology (AFIT) conducts extensive research in advanced guidance, navigation, and control to exploit the full potential of autonomous Unmanned Aerial Vehicles (UAV). The research in this thesis describes a UAV research platform developed to support the ANT Center's goals. This platform is now the bedrock for UAV simulation and local flight test at AFIT. The research has three major components. The first component is development of a physical, inertial, and aerodynamic model representing an existing aircraft. A systematic analysis of the airframe leads to a complete geometric, inertial, …
Stochastic Capability Models For Degrading Satellite Constellations, Cole W. Gulyas
Stochastic Capability Models For Degrading Satellite Constellations, Cole W. Gulyas
Theses and Dissertations
This thesis proposes and analyzes a new measure of functional capability for satellite constellations that incorporates the instantaneous availability and mission effectiveness of individual satellites. The capability measure yields a continuous score between zero and one accounting for the degree to which the constellation meets operational requirements. The measure is computed from an average of satellite capabilities, composed of the product of the satellite's instantaneous availability and value score. Instantaneous availability is acquired by modeling the satellite degradation status as either a time-homogenous, continuous-time Markov chain (CTMC) if it possesses functions with exponential lifetime distributions, or as a time-homogenous, semi-Markov …
An Approach For Optimizing The On-Orbit Servicing Architecture For The Space-Based Radar Constellation, Michael L. Mcconnell
An Approach For Optimizing The On-Orbit Servicing Architecture For The Space-Based Radar Constellation, Michael L. Mcconnell
Theses and Dissertations
Satellite systems, once operational, are essentially a consumable item with no capacity to maintain, repair, or upgrade them while on-orbit. In order to avoid having to replace costly space assets, the Defense Advanced Research Projects Agency (DARPA) and Air Force Space Command (AFSPC) are looking to developing programs to provide an on-orbit servicing capability for future satellite systems under development, such as the Space-Based Radar (SBR) system. DARPA and AFSPC are studying on-orbit servicing using the Orbital Express platform as part of an Analysis of Alternatives for the SBR program. Like their satellite clients, on-orbit servicing assets are expected to …