Browsing by Department "Aerospace Engineering"
Now showing items 120 of 172

Acoustic waveforms produced by a laboratory scale supersonic jet
(201408)The spatial evolution of acoustic waveforms produced by a Mach 3 jet are investigated using both 1/4 inch and 1/8 inch pressure field microphones located along rays emanating from the post potential core where the peak ... 
Acoustics from highspeed jets with crackle
(201305)A scaling model based on an effective Gol'dberg number is proposed for predicting the presence of cumulative nonlinear distortions in the acoustic waveforms produced by highspeed jets. Two acoustic length scales, the shock ... 
Adaptation, gyroree stabilization, and smooth angular velocity observers for attitude tracking control applications
(201408)This dissertation addresses the problem of rigidbody attitude tracking control under three scenarios of high relevance to many aerospace guidance and control applications: adaptive attitudetracking control law development ... 
Adaptive and convergent methods for large eddy simulation of turbulent combustion
(201408)In the recent past, LES methodology has emerged as a viable tool for modeling turbulent combustion. LES computes the large scale mixing process accurately, thereby providing a better starting point for smallscale models ... 
Adaptive control for doubleintegrator class systems in the absence of velocity feedback
(201212)This work considers formulation of new classes of adaptive controllers for doubleintegrator type systems where the underlying system parameters are uncertain and the complete statevector is not available for feedback. ... 
Adaptive estimation and control algorithms for certain classes of largescale sensor and actuator uncertainties
(201205)This dissertation considers the general problem of controlling dynamic systems subject to largescale sensor and actuator uncertainties. The assumption is made that the uncertainty is limited to either pure rotation (i.e. ... 
Adaptive finite element simulation of flow and transport applications on parallel computers
(200705)The field of molecular and atomic sensing has seen a vast growth over the last few decades. Yet many advances still remain to be made. This dissertation takes an in depth look at the two major aspects in a molecular ... 
Alignment filtering of ICESat flight data
(201212)ICESat consisted of the Geoscience Laser Altimeter System (GLAS) and a commercial spacecraft bus. The stability of the GLAS to bus alignment was unknown and significant for GLAS pointing. Pointing control was performed by ... 
Analysis of the characteristics of grace dual oneway ranging system
(200805)The motivation for this research was an improvement of the quality of the Earth’s gravity solutions from the GRACE mission data through an instrumentlevel study. The objective was a better understanding of the characteristics ... 
An analytical approach to computing step sizes for finitedifference derivatives
(201205)Finitedifference methods for computing the derivative of a function with respect to an independent variable require knowledge of the perturbation step size for that variable. Although rules of thumb exist for determining ... 
Analytical approach to the design of optimal satellite constellations for spacebased space situational awareness applications
(201112)In recent years, the accumulation of space debris has become an increasingly pressing issue, and adequately monitoring it is a formidable task for designated groundbased sensors. Supplementing the capabilities of these ... 
The application of systems engineering to a Spacebased Solar Power Technology Demonstration Mission
(201205)This thesis presents an endtoend example of systems engineering through the development of a Spacebased Solar Power Satellite (SSPS) technology demonstration mission. As part of a higher education effort by NASA to ... 
Application Of The MCMC Method For The Calibration Of DSMC Parameters
(201105)A Markov Chain Monte Carlo (MCMC) algorithm was employed to obtain a calibrated distribution for the hard sphere diameter, the VHS reference diameter, and the temperature viscosity exponent of argon, for use in the Direct ... 
An architecture for incorporating interactive visualizations into scientific simulations
(200605)As scientific simulations get increasingly complex, so do the requirements of how to deal with the data that is produced. Few scientists and engineers today are satisfied with just looking at streams of numbers; we require ... 
Assessment of numerical differentiation methods for kinematic orbit solution of the GRACE mission
(201212)The historical method of precise orbit determination is a dynamic approach. However, with the improvement of GPS tracking data and associated tracking networks, two newer methods have been developed: reduceddynamic and ... 
An assessment of the GPS L5 signal based on multiple vendor receivers
(201112)The L5 signal of the Global Positioning System (GPS) is becoming available on an increasing number of Block IIF satellites. As the third civilian signal, L5 is superior in signal design to the L1 C/A and L2C civilian ... 
An attitude determination and control system for small satellites
(201505)A flexible, robust attitude determination and control (ADC) system is presented for small satellite platforms. Using commercialofftheshelf sensors, reaction wheels, and magnetorquers which fit within the 3U CubeSat form ... 
Automatic algorithm for accurate numerical gradient calculation in general and complex spacecraft trajectories
(201012)An automatic algorithm for accurate numerical gradient calculations has been developed. The algorithm is based on both finite differences and Chebyshev interpolation approximations. The novelty of the method is an automated ... 
The autonomous guidance, navigation, and control laboratory at the University of Texas at Austin
(201512)This report details the design, construction, and contents of the Autonomous Guidance, Navigation, and Control Laboratory (AGNC Lab) for Dr. Behcet Acikmese at the University of Texas. It is intended as a resource for those ... 
Autonomous timeoptimal spacecraft rendezvous and proximity operations using stabilized continuation
(20160629)This thesis addresses the minimumtime rendezvous optimal control problem by implementing continuation with a stabilizing input. The rendezvous problem is first formulated as an optimal control problem which is then ...