Aerospace Engineering Commons^™

Evaluation Of Probabilistic Methodology For Predicting Satellite Tracking Resources, Matthew Lynn Stubbe

Master's Theses - Daytona Beach

This research evaluates a probabilistic methodology for estimating the ability of satellite tracking networks to provide tracking and data acquisition services to large constellations of satellites. This approach, developed by Hagar is evaluated using Monte Carlo simulations of optimal satellite contact scheduling on a tracking network for a certain class of satellites. The actual results of the scheduled Monte Carlo simulations were then compared to the predicted values computed with Hagar's methodology for a range constellation and network sizes. Comparison methods include percent difference, a Wilcoxon signed ranks test and a Mann-Whitney U test.

The Monte Carlo simulations were run …

Flow Control Of Airfoil At Post-Stall Conditions By Multiple Frequency Applied Saado Jets, A. Şamil Demirsöz

Mechanical & Aerospace Engineering Theses & Dissertations

Flow separation over lifting aerodynamic components, such as airfoils and wings, occurs during stall conditions which are caused by adverse changes (i.e.; high angle of attack, inflow conditions, etc.) in the operating conditions of aerodynamic components. During stall conditions, the flow over airfoil loses its momentum, creating high pressure zones on the upper surface of the airfoil and even a small increase in pressure causes the fluid particles to stop and separate to a low pressure zone. In order to eliminate the flow separation, the low momentum flow should be removed in order to maintain the high momentum and low …

T. I. Tech Arliss Team: Spopovic, Tokyo Insititute Of Technology Arliss Team

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint presentation created by the Tokyo Insititute of Technology ARLISS Team titled "T. I. Tech ARLISS Team: Spopovic" from September 23, 2006.

Come-Back Competition: 2006 Summary, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint presentation created by Professor Bob Twiggs titled "Come-Back Competition: 2006 Summary" from September 23, 2006.

Arliss 2006 Cansat: Da Vinci, Matsunaga Lab, Tokyo Institute Of Technology

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint presentation created by the Matsunaga Lab of Tokyo Institute of Technology titled "ARLISS 2006 CanSat: Da Vinci" from September 23, 2006.

Arliss 2006 Report, Tohoku University Sekiguteam

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint presentation created by the Tohoku University Sekiguteam  titled "ARLISS 2006 Report" from September 23, 2006.

Arliss 2006: University Of Tokyo & Seoul National University, Team Snut

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint presentation created Team SNUT titled "ARLISS 2006: University of Tokyo & Seoul National University" from September 23, 2006.

Samurai, University Of Tokyo Rover Team

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint presentation created by the University of Tokyo Rover Team titled "Samurai" from September 23, 2006.

Cbc-03: Nihon University, Yuta Chiba, Yuta Kujira

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint presentation created by Yuta Chiba and Yuta Kujira titled "CBC-03: Nihon University" from September 23, 2006.

Airsat Project: Design And Construction Of An Autonomous Atmospheric Probe, Jornados De Jovenes Cientificos

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint presentation created by the Jornadas de Jóvenes Científicos titled "AIRSat Project: Design and construction of an autonomous atmospheric probe" from September 23, 2006.

Arliss 2006: Comeback Competition Report, Tohoku University Yashago Team

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint presentation created by the Tohoku University Yashago Team titled "ARLISS 2006: Comeback Competition Report" from September 22, 2006.

Result Of Arliss "Coolrunning Ver. 3", Osamu Kitagawara, Yusuke Saisoh

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint presentation created by Osamu Kitagawara and Yusuke Saison titled "Result of ARLISS CoolRunning Ver. 3" from September 22, 2006.

Aoyama Gakuin University: I Can Fly, Kuninori Togai, Satoshi Adachi, Naoki Kitabayashi

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint presentation created by the Aoyama Gakuin University Space Club on September 22, 2006.

Mavericks & 2007 International Civilian Space Competition, Thomas M. Atchison

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Thomas M. Atchison titled "Mavericks & 2007 International Civilian Space Competition" from September 22, 2006.

Error Allocation In Complex Systems Design, Robert A. Mcdonald

Aerospace Engineering

A fidelity trade environment was conceived, formulated, developed, and demonstrated. This development relied on the advancement of enabling techniques including error propagation, metamodeling, and information management. These techniques were integrated with an existing commercial systems design framework and an intuitive graphical interface to create a fidelity trade environment. A sensitivity approach to the propagation of error through complex systems was developed. This approach relied on the system sensitivity matrix to model the behavior of a complex system as a whole. In verification tests, the sensitivity approach provided approximate results substantially similar to a Monte Carlo approach that was many orders …

Lightweight In-Plane Actuated Deformable Mirrors For Space Telescopes, Michael J. Shepherd

Theses and Dissertations

This research focused on lightweight, in-plane actuated, deformable mirrors, with the ultimate goal of developing a 20- meter light gathering aperture for space telescopes. The 0.127 meter diameter deformable mirror small scale testbed was modelled infinite elements using MSC.Nastran software and then used as a basis for a quasi-static controller. Experimental tracking of Zernike tip, tilt, and defocus modes was accomplished. The analytical solutions to plate-membrane and beam-string ordinary differential equations were developed. A simplified approach to modelling the axisymmetric cases was also presented. A novel static control strategy, the Modal Transformation Method, was developed to form Zernike surfaces within …

Dynamics And Control Of Tethered Satellite Formations For The Purpose Of Space-Based Remote Sensing, Kurt A. Vogel

Theses and Dissertations

This dissertation assesses the utility of tethered satellite formations for the space-based remote sensing mission. Energy dissipation is found to have an adverse effect on foundational rigid body (Likins-Pringle) equilibria. It is shown that a continuously earth-facing equilibrium condition for a fixed-length tethered system does not exist since the spin rate required for the proper precession would not be high enough to maintain tether tension. The range of required spin rates for steady-spin motion is numerically defined here, but none of these conditions can meet the continuously earth-facing criteria. Of particular note is the discovery that applying certain rigid body …

An Investigation Of The Effects Of Boundary Avoidance On Pilot Tracking, Randy D. Warren

Theses and Dissertations

Pilot-Involved Oscillations (PIOs) remain a significant issue in the design, testing and operations of aerospace vehicles. Traditional methods for predicting, describing, and analyzing these events have provided the community with improved methods for minimizing the occurrences of PIOs. However, these events continue to occur over a wide range of aerospace vehicle types and over a wide range of pilot acumen. The introduction of boundary avoidance tracking (BAT) by Mr. William Gray in 2004 added a missing piece to the PIO puzzle. This theory presented that PIOs may result from increasing pilot gain resulting not from maintaining a specified condition, but …

Scaling Flight Tests Of Unmanned Air Vehicles, Jeevani I. Abeygoonewardene

Theses and Dissertations

Increasing technological advances and research interest in unmanned air vehicles (UAVs), have led to the need for having safe, inexpensive and effective means of experimenting with their fight performance and surveillance capabilities. Work has previously been done in areas of controlling, analyzing, and predicting cooperative and autonomous operations of UAVs and other vehicles. In addition, there are well established guidelines for scaling experiments in fluid mechanics, where geometric, kinematic and dynamic similarity is obtained by formulating problems in terms of non dimensional variables using dimensional analysis. However, little or no work has been done in developing experiments or guidelines for …

Three Component Velocity Measurements In The Tip Vortex Of A Micro-Air-Vehicle, Hong-Joon Park

Theses and Dissertations

The purpose of this research was to improve the MAV that will be used for battle damage assessment and reconnaissance or local surveillance through the experiments in AFIT wind tunnel. The experiments were performed to investigate the wing displacement and wing tip vortex interaction. To conduct the experiments, telescopic survey tool and tri-axial hot-wire anemometer was utilized. The results indicate that wing tip displacement of the flexible wing was approximately 8 times that of the rigid wing in an unstalled condition and data suggests that flexible wing has a denser core-distribution of velocity within the wing tip vortex and delays …

Parameter Estimation Of A Tactical Missile Using Linear Regression, Kelly S. Powers

Theses and Dissertations

This research presents the method of Linear Regression as a parameter identification method to determine the longitudinal dimensional stability derivatives of a tactical missile. Missile flight histories are characterized by rapid accelerations, rapidly changing mass property characteristics with often short flight times. These characteristics make accurate parameter estimation of the missile aerodynamics more challenging than for aircraft. The simulation used for this research was created in MATLAB/SIMULINK based on the missile trajectory program, TRAP. The aerodynamic data for the 6- DoF missile model was based on a supersonic, tail controlled missile similar to an AIM-9X missile. Two command input types …

Navigation Using Signals Of Opportunity In The Am Transmission Band, Jonathan A. Mcellroy

Theses and Dissertations

Maintaining a precision navigation solution both in a GPS hostile jamming environment and also in a GPS non-compatible terrain area is of great importance. To that end, this thesis evaluates the ability to navigate using signals from the AM band of the electromagnetic spectrum (520 to 1710 kHz). Navigation position estimates are done using multi-lateration techniques similar to GPS. However, pseudoranges are created using Time Difference of Arrival (TDOA) distances between a reference receiver and a mobile receiver, allowing the mobile receiver to obtain absolute position estimates over time. Four methods were developed for estimating the cross-correlation peak within a …

Development And Testing Of A High-Speed Real-Time Kinematic Precise Dgps Positioning System Between Two Aircraft, Christopher J. Spinelli

Theses and Dissertations

This research involves the design, implementation, and testing of a high-speed, real-time kinematic, precise differential GPS positioning system for use in airborne applications such as automated aerial-refueling and close formation flying. Although many of the current ambiguity resolution techniques use the residuals from the least squares position estimation to determine the true ambiguity set, this thesis presents a novel approach to the ambiguity resolution problem, called the minimum indicator. Instead of assuming the ambiguity set with the lowest residuals is the true set, other special characteristics of the residuals are examined. This increases the confidence that the algorithm has selected …

Optimal Dynamic Soaring For Full Size Sailplanes, Randel J. Gordon

Theses and Dissertations

Dynamic soaring is a unique flying technique designed to allow air vehicles to extract energy from horizontal wind shears. Dynamic soaring has been used by seabirds like the Albatross to fly hundreds of kilometers a day across the ocean. Small hobby radio controlled sailplanes have also used this technique to achieve sustained speeds of over 200 miles per hour from just a simple hand toss. Dynamic soaring, however, has never before been studied for use on full size aircraft. The primary goal of this research was to prove or disprove the viability of dynamic soaring for enhancing a full size …

Design And Numerical Simulation Of Two Dimensional Ultra Compact Combustor Model Sections For Experimental Observation Of Cavity-Vane Flow Interactions, David S. Moenter

Theses and Dissertations

An improved computational fluid dynamics (CFD) model was developed for numerical simulation of the Ultra Compact Combustor (UCC) concept to enhance turbulent flow characterization of the circumferentially traveling, centrifugal-force enhanced combustion, cavity flow into the engine main flow passage via a radial cavity in the turbine axial guide vanes. The CFD model uses a dense grid on a 60° periodic, axisymmetric combustor section, with the RNG κ-ε turbulence model to resolve turbulent flow details. An overall analysis and performance evaluation of the experimentally tested UCC configuration and an axially shortened cavity baseline configuration was conducted at various experimentally documented operating …

Grain Growth Behavior At Absolute Zero During Nanocrystalline Metal Indentation, F. Sansoz, V. Dupont

Aerospace Engineering - Daytona Beach

The authors show using atomistic simulations that stress-driven grain growth can be obtained in the athermal limit during nanocrystalline aluminum indentation. They find that the grain growth results from rotation of nanograins and propagation of shear bands. Together, these mechanisms are shown to lead to the unstable migration of grain boundaries via process of coupled motion. An analytical model is used to explain this behavior based on the atomic-level shear stress acting on the interfaces during the shear band propagation. This study sheds light on the atomic mechanism at play during the abnormal grain coarsening observed at low temperature in …

Modeling Fracture In Z-Pinned Composite Co-Cured Laminates Using Smeared Properties And Cohesive Elements In Dyna3d, Jason K. Freels

Theses and Dissertations

The purpose of the present research was three-fold: 1) gain a more sophisticated understanding of the response of co-cured composite joints with and without through-thickness reinforcement (TTR), 2) compare the behavior of specimens reinforced with various sizes and densities of reinforcement, and 3) use experimental data to verify the existing DYNA3D smeared property model. Double cantilever beam, end-notch flexure and T-section specimens reinforced with 0.011" diameter z-pins at 2% and 4% volume densities were tested to determine the mode I, mode II and mixed mode (I and II) behavior. Results were added to preliminary research in which tests were conducted …

Development Of A Low-Latency, High Data Rate, Differential Gps Relative Positioning System For Uav Formation Flight Control, Stephen J. Comstock

Theses and Dissertations

In order for Unmanned Aerial Vehicles (UAVs) to be able to fly missions currently performed by manned aircraft, they must be able to conduct in-flight refueling. Additionally, significant fuel savings can be realized if multiple UAV's are able to fly in precise formation and align wingtip vortices. In either case, the precise relative position between the aircraft must be known to an accuracy of only a few centimeters. Previous research at the Air Force Institute of Technology culminated in the development of a relative positioning system for manned aircraft. This thesis presents the development of the next-generation system designed for …

Fusion Of Imaging And Inertial Sensors For Navigation, Michael J. Veth

Theses and Dissertations

The motivation of this research is to address the limitations of satellite-based navigation by fusing imaging and inertial systems. The research begins by rigorously describing the imaging and navigation problem and developing practical models of the sensors, then presenting a transformation technique to detect features within an image. Given a set of features, a statistical feature projection technique is developed which utilizes inertial measurements to predict vectors in the feature space between images. This coupling of the imaging and inertial sensors at a deep level is then used to aid the statistical feature matching function. The feature matches and inertial …

Dual Fine Tracking Control Of A Satellite Laser Communication Uplink, Louis A. Noble

Theses and Dissertations

A dual fine tracking control system (FTCS) is developed for a single aperture optical communication receiver to compensate for high frequency disturbances affecting tracking of two incident laser communication beams. The optical communication receiver resides within a payload module aboard a geosynchronous satellite, while each laser communication transmitter is housed within a module aboard a high altitude unmanned aerial vehicle (UAV). In addition to platform specific disturbances, the impact of atmospheric optical disturbances affecting tracking error are investigated. The system dynamics and FTCS are modeled and evaluated in MATLAB and SIMULINK. An optimal controller is developed to mitigate these disturbances …