Aerospace Engineering Commons^™

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 …

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 …

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

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 …

Aerial Networking For The Implementation Of Cooperative Control On Small Unmanned Aerial Systems, Scott A . Songer

Theses and Dissertations

The employment of Small Unmanned Aerial Systems (SUAS) for reconnaissance and surveillance missions is a vital capability of the United States military. Cooperative control algorithms for SUAS can enable tactical multi-vehicle configurations for communications extension, intelligent navigation, and a multitude of other applications. Past research at AFIT has designed and simulated a cooperative rover-relay algorithm for extended communications and has investigated its implementation through various modem configurations. This research explores aerial networking options for implementing cooperative control and applies them to an actual SUAS. Using Commercial Off-The-Shelf (COTS) hardware, a system was designed and flight tested to implement the rover-relay …

Design Of A Control Moment Gyroscope Attitude Actuation System For The Attitude Control Subsystem Proving Ground, Samuel C. Johnson

Theses and Dissertations

All spacecraft represent a considerable investment of both time and money. To ensure mission success, testing and validation of all vital systems is crucial to the design process. The attitude control subsystem (ACS) is typically tested thoroughly, to include both hardware and control algorithms. Computer simulations offer a simple and relatively cheap method of predicting the performance of the ACS; however, computer simulations cannot provide the assurances necessary to qualify an ACS hardware configuration or control algorithm spaceworthy. For this reason, physical spacecraft simulators must be used to validate ACS dynamics. Previous research showed there is room for significant improvement …

Comm-Using Decibels, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs on "Comm-Using Decibels" from March 14, 2014.

Towards A “Cloud Curriculum” In Art And Science?, Roger Malina

The Transdisciplinary STEAM+ Journal

Recently an email hit my desk from Paul Thomas in Australia with a proposal to work together on a “Cloud Curriculum for Art and Science”. I immediately agreed to collaborate. I don’t yet have a clue of what a cloud curriculum is, but what I do know is that we are ‘backing into the future’ in educational institutions and we desperately need a ‘cloud curriculum.’ We need to look over the ten year horizon. And in the emerging art-science field I doubt that the usual approach to curriculum development will work.

Design Of A Specimen Fixture For Impact Resistance Testing In An Instron Dynatup 8250 Drop Weight Impact Tester, Daniel Alejandro Barath

Aerospace Engineering

The purpose of this report is to outline the path and methods used to design a specimen fixture for the testing and analysis of fiber reinforced composites subjected to impact loading. This design is done in support of the California Polytechnic State University in San Luis Obispo Structures and Composites Laboratory. The design request was made at the request of Dr. Eltahry Elghandour to support the graduate students Kodi A. Rider and Y. Vanessa Wood in their master’s degree thesis projects.

The design request involved the design of a specimen fixture compatible with the existing impact apparatus located in the …

Influence Of Wing Span On The Aerodynamics Of Wings In Ground Effect, Sammy Diasinos, Tracie J. Barber, Graham Doig

Aerospace Engineering

A computational fluid dynamics study of the influence of wing span has been conducted for an inverted wing with endplates in ground effect. Aerodynamic coefficients were determined for different spans at different ground clearances, highlighting a trend for shorter spans to delay the onset of both separation and resulting loss of negative lift. The vortices at the wing endplates were not observed to change significantly in terms of strength and size; thus, at shorter spans, their influence over a larger percentage of the wing helped the flow stay attached and reduced the severity of the adverse pressure gradient which invokes …

Implementing A Matlab Based Attitude Determination Algorithm In C Within The Polysat Software Architecture, Dominic Bertolino

Computer Engineering

This project focuses on one component within a complete attitude determination and control system (ADCS) for a small satellite. The component consists of porting the algorithm that determines the current attitude of the satellite developed by AERO students / team members. The original algorithm has been developed in MATLAB code. The actual algorithm will be simulated and tested in MATLAB by the AEROs. The porting consisted of integrating the pieces into the custom PolySat software environment in C. Testing was done to verify the ported component corresponded to the original MATLAB component as well as verify its runtime on the …

Senior Project Report - Doctest, Stephen Weessies

Computer Engineering

DocTest is a program that, simply put, allows a programmer or user to document STANAG 4586 (a standard for unmanned aerial vehicle interoperability) messages and test the vehicle system at Lockheed Martin [5]. The program is extensible to allow for further development aiding our software team to do what they do best and not get bogged down in tedious but necessary documentation. DocTest is also used to aid in testing, keeping track of the issues and bugs found and creating a document that captures each issue so an issue is not missed or forgotten. This program was made for use …

Axisymmetric Air Augmented Methanol/Gox Rocket Mixing Duct Experimental Thrust Study, Kyle Jacob Johnson

Master's Theses

A hot-flow axisymmetric Air Augmented Rocket (AAR) test apparatus was constructed to test various mixing duct configurations at static conditions. Primary flow for the AAR was provided through a liquid methanol-gaseous oxygen bipropellant rocket. Experimental thrust measurements were recorded and propellant mass flow rates and chamber conditions were calculated using an iterative solver dependant on recorded propellant line stagnation pressures. Primary rocket flow produced thrust ranging from 14 to 17.9lbf. Primary mass flow rate through testing ranged from 0.071 to 0.085lbm/s with calculated chamber pressures between 298-362psia. Calculated primary flow velocity ranged from 6,600ft/s to 8,000ft/s depending on propellant pressure …

A Gravity Gradient, Momentum-Biased Attitude Control System For A Cubesat, Ryan J. Sellers

Master's Theses

ExoCube is the latest National Science Foundation (NSF) funded space weather CubeSat and is a collaboration between PolySat, Scientific Solutions Inc. (SSI), the University of Wisconsin, NASA Goddard and SRI International. The 3U will carry a mass spectrometer sensor suite, EXOS, in to low earth orbit (LEO) to measure neutral and ionized particles in the exosphere and thermosphere. Measurements of neutral and ion particles are directly impacted by the angle at which they enter EXOS and which leads to pointing requirements. A combination of a gravity gradient system with a momentum bias wheel is proposed to meet pointing requirements while …

Ad-Hoc Regional Coverage Constellations Of Cubesats Using Secondary Launches, Guy G. Zohar

Master's Theses

As development of CubeSat based architectures increase, methods of deploying constellations of CubeSats are required to increase functionality of future systems. Given their low cost and quickly increasing launch opportunities, large numbers of CubeSats can easily be developed and deployed in orbit. However, as secondary payloads, CubeSats are severely limited in their options for deployment into appropriate constellation geometries.

This thesis examines the current methods for deploying cubes and proposes new and efficient geometries using secondary launch opportunities. Due to the current deployment hardware architecture, only the use of different launch opportunities, deployment direction, and deployment timing for individual cubes …

Design And Performance Of Circulation Control Geometries, Rory Martin Golden

Master's Theses

With the pursuit of more advanced and environmentally-friendly technologies of today’s society, the airline industry has been pushed further to investigate solutions that will reduce airport noise and congestion, cut down on emissions, and improve the overall performance of aircraft. These items directly influence airport size (runway length), flight patterns in the community surrounding the airport, cruise speed, and many other aircraft design considerations which are setting the requirements for next generation aircraft. Leading the research in this movement is NASA, which has set specific goals for the next generation regional airliners and has categorized the designs that meet the …

Film Cooling In Fuel Rich Environments, Jacob J. Robertson

Theses and Dissertations

The ultra compact combustor is a high performance gas turbine design concept that portends reduced weight for future weapons platforms. A natural outcome of the design is the continual presence of fuel-rich air in the turbine component of the engine. Because modern cooling schemes for hot section turbine blades involve injecting cool, oxygen-rich air adjacent to the surface, the potential arises for reaction with the unconsumed radicals in the mainstream ow and augmented heat transfer to the blade. This outcome is contrary to the purpose of film cooling, and can lead to early life-cycle turbine failure. This study examined the …

Design And Testing Of An H2/O2 Predetonator For A Simulated Rotating Detonation Engine Channel, Stephen J. Miller

Theses and Dissertations

A study is presented on the relationship between a pre-detonator and a detonation channel of an RDE. Testing was conducted on a straight narrow channel made of clear polycarbonate windows connected to an H₂/O₂ pre-detonator to simulate the RDE initiation scheme and allow for flow visualization. A comparison is made on decoupling distance and wave velocities for a range of pre-detonator designs, inclination angles, equivalence ratios and geometries placed within the simulated channel. Regardless of inclination angle or equivalence ratio the detonation wave decoupled within 25 mm from the pre-detonator exit into the channel. A step change …

Work Ethics For Sse-122: Satellites & Space Systems (Spring 2013), Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

PowerPoint presentation by Professor Bob Twiggs on work ethics for SSE-122: Satellites & Space Systems for the spring 2013 semester, created on February 28, 2013.

Equilibrium And Nonequilibrium Molecular Dynamics Simulations Of Thermal Conductance At Solid-Gas Interfaces, Zhi Liang, William Evans, Pawel Keblinski

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The Thermal Conductance at Solid-Gas Interfaces with Different Interfacial Bonding Strengths is Calculated through Green-Kubo Equilibrium Molecular Dynamics (EMD) Simulations. Due to the Finite Size of the Simulation System, the Long-Time Integral of the Time Correlation Function of Heat Power Across the Solid-Gas Interface Exhibits an Exponential Decay, Which Contains the Information on Interfacial Thermal Conductance. If an Adsorbed Gas Layer is Formed on the Solid Surface, It is Found that the Solid-Gas Interface Needs to Be Defined at a Plane Outside the Adsorbed Layer So as to Obtain the Correct Result from the Green-Kubo Formula. the EMD Simulation Result …