+publisher:"University of Colorado" +contributor:("Brandon Jones")

University of Colorado

1. Geeraert, Jeroen L. Multi-Satellite Orbit Determination Using Interferometric Observables with RF Localization Applications.

Degree: PhD, 2017, University of Colorado

URL: https://scholar.colorado.edu/asen_gradetds/192

► Very long baseline interferometry (VLBI) specifically same-beam interferometry (SBI), and dual-satellite geolocation are two fields of research not previously connected. This is due to… (more)

▼ Very long baseline interferometry (VLBI) specifically same-beam interferometry (SBI), and dual-satellite geolocation are two fields of research not previously connected. This is due to the different application of each field, SBI is used for relative interplanetary navigation of two satellites while dual-satellite geolocation is used to locate the source of a radio frequency (RF) signal. In this dissertation however, we leverage both fields to create a novel method for multi-satellite orbit determination (OD) using time difference of arrival (TDOA) and frequency difference of arrival (FDOA) measurements. The measurements are double differenced between the satellites and the stations, in so doing, many of the common errors are canceled which can significantly improve measurement precision. Provided with this novel OD technique, the observability is first analyzed to determine the benefits and limitations of this method. In all but a few scenarios the measurements successfully reduce the covariance when examining the Cramér-Rao Lower Bound (CRLB). Reduced observability is encountered with geostationary satellites as their motion with respect to the stations is limited, especially when only one baseline is used. However, when using satellite pairs with greater relative motion with respect to the stations, even satellites that are close to, but not exactly in a geostationary orbit can be estimated accurately. We find that in a strong majority of cases the OD technique provides lower uncertainties and solutions far more accurate than using conventional OD observables such as range and range-rate while also not being affected by common errors and biases. We specifically examine GEO-GEO, GEO-MEO, and GEO-LEO dual-satellite estimation cases. The work is further extended by developing a relative navigation scenario where the chief satellite is assumed to have perfect knowledge, or some small amount of uncertainty considered but not estimated, while estimating the deputy satellite state with respect to the chief. Once again the results demonstrate that the TDOA and FDOA OD results are favorable with faster dynamics over classical measurements. This dissertation not only explores the OD side, but also gaps in geolocation research. First the mapping of ephemeris uncertainty to the geolocation covariance to provide a more realistic covariance was implemented. Furthermore, the geolocation solution was improved by appending a probabilistic altitude constraint to the posterior covariance, significantly reducing the projected geolocation uncertainty ellipse. The feasibility of using the geolocation setup to passively locate a LEO satellite was also considered. Finally the simulated results were verified using a long-arc of real data. The use of FDOA for small-body navigation and gravity recovery was also examined as an extended application. Advisors/Committee Members: Jay W. McMahon, Penina Axelrad, Brandon Jones, Daniel Scheeres, Behrouz Touri.

Subjects/Keywords: astrodynamics; geolocation; interferometry; orbit determination; Aerospace Engineering

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APA (6^th Edition):

Geeraert, J. L. (2017). Multi-Satellite Orbit Determination Using Interferometric Observables with RF Localization Applications. (Doctoral Dissertation). University of Colorado. Retrieved from https://scholar.colorado.edu/asen_gradetds/192

Chicago Manual of Style (16^th Edition):

Geeraert, Jeroen L. “Multi-Satellite Orbit Determination Using Interferometric Observables with RF Localization Applications.” 2017. Doctoral Dissertation, University of Colorado. Accessed March 04, 2021. https://scholar.colorado.edu/asen_gradetds/192.

MLA Handbook (7^th Edition):

Geeraert, Jeroen L. “Multi-Satellite Orbit Determination Using Interferometric Observables with RF Localization Applications.” 2017. Web. 04 Mar 2021.

Vancouver:

Geeraert JL. Multi-Satellite Orbit Determination Using Interferometric Observables with RF Localization Applications. [Internet] [Doctoral dissertation]. University of Colorado; 2017. [cited 2021 Mar 04]. Available from: https://scholar.colorado.edu/asen_gradetds/192.

Council of Science Editors:

Geeraert JL. Multi-Satellite Orbit Determination Using Interferometric Observables with RF Localization Applications. [Doctoral Dissertation]. University of Colorado; 2017. Available from: https://scholar.colorado.edu/asen_gradetds/192

University of Colorado

2. Hadigol, Mohammad. Uncertainty Quantification of Coupled Problems with Applications to Lithium-ion Batteries.

Degree: PhD, Aerospace Engineering Sciences, 2016, University of Colorado

URL: https://scholar.colorado.edu/asen_gradetds/137

► This thesis includes three main parts that are concerned with the propagation of uncertainty across high-dimensional coupled problems with applications to Lithium-ion batteries (LIBs).… (more)

▼ This thesis includes three main parts that are concerned with the propagation of uncertainty across high-dimensional coupled problems with applications to Lithium-ion batteries (LIBs). In all three parts, spectral methods involving polynomial chaos expansions (PCEs) are employed to quantify the effects of propagating the input uncertainties across the system. In the first part, a stochastic model reduction approach based on low-rank separated representations is proposed for the partitioned treatment of the uncertainty space in coupled domain problems. Sequential construction of the sub-domain solutions with respect to the stochastic dimensionality of each sub-domain enabled by the classical FETI method drastically reduces the overall computational cost and provides a well suited framework for parallel computing. Two high-dimensional stochastic problems, a 2D elliptic PDE with random diffusion coefficient and a stochastic linear elasticity problem, have been considered to study the performance and accuracy of the proposed stochastic coupling approach. A sampling-based UQ framework to study the effects of input uncertainties on the performance of LIBs using a full-order physics-based electrochemical model is presented in the second part. Developed based on sparse PCEs, the proposed UQ technique enables one to study the effects of LIB model uncertainties on the cell performance using a fairly small number of battery simulations. An LiC₆/LiCoO₂ cell with 19 random parameters has been considered to study the performance and accuracy of the proposed UQ approach. It was found that the battery discharge rate is a key factor affecting not only the performance variability of the cell, but also the determination of most important random inputs. The third part provides a comprehensive review of the sampling techniques for the regression-based PCEs. Traditional sampling methods such Monte Carlo, Latin hypercube, quasi-Monte Carlo, optimal design of experiments, Gaussian quadratures as well as more recent techniques such as coherence-optimal and randomized quadratures are discussed. In addition, hybrid sampling methods referred to by the alphabetic coherence-optimal techniques which are a combination of the alphabetic optimality criteria and the coherence-optimal sampling method are proposed. It was observed that the alphabetic-coherence-optimal techniques outperform other sampling methods, specially when high-order PCEs are employed and/or the oversampling ratio is low. Advisors/Committee Members: Alireza Doostan, Kurt Maute, Carlos Felippa, Se-Hee Lee, Brandon Jones.

Subjects/Keywords: Coupled Domain; High-dimensional; Lithium-ion Battery; Optimal Sampling; Polynomial Chaos Expansion; Uncertainty Quantification; Applied Mathematics; Engineering; Power and Energy

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APA (6^th Edition):

Hadigol, M. (2016). Uncertainty Quantification of Coupled Problems with Applications to Lithium-ion Batteries. (Doctoral Dissertation). University of Colorado. Retrieved from https://scholar.colorado.edu/asen_gradetds/137

Chicago Manual of Style (16^th Edition):

Hadigol, Mohammad. “Uncertainty Quantification of Coupled Problems with Applications to Lithium-ion Batteries.” 2016. Doctoral Dissertation, University of Colorado. Accessed March 04, 2021. https://scholar.colorado.edu/asen_gradetds/137.

MLA Handbook (7^th Edition):

Hadigol, Mohammad. “Uncertainty Quantification of Coupled Problems with Applications to Lithium-ion Batteries.” 2016. Web. 04 Mar 2021.

Vancouver:

Hadigol M. Uncertainty Quantification of Coupled Problems with Applications to Lithium-ion Batteries. [Internet] [Doctoral dissertation]. University of Colorado; 2016. [cited 2021 Mar 04]. Available from: https://scholar.colorado.edu/asen_gradetds/137.

Council of Science Editors:

Hadigol M. Uncertainty Quantification of Coupled Problems with Applications to Lithium-ion Batteries. [Doctoral Dissertation]. University of Colorado; 2016. Available from: https://scholar.colorado.edu/asen_gradetds/137

University of Colorado

3. Gehly, Steven. Estimation of Geosynchronous Space Objects Using Finite Set Statistics Filtering Methods.

Degree: PhD, Aerospace Engineering Sciences, 2016, University of Colorado

URL: https://scholar.colorado.edu/asen_gradetds/148

► The use of near Earth space has increased dramatically in the past few decades, and operational satellites are an integral part of modern society. The… (more)

▼ The use of near Earth space has increased dramatically in the past few decades, and operational satellites are an integral part of modern society. The increased presence in space has led to an increase in the amount of orbital debris, which poses a growing threat to current and future space missions. Characterization of the debris environment is crucial to our continued use of high value orbit regimes such as the geosynchronous (GEO) belt. Objects in GEO pose unique challenges, by virtue of being densely spaced and tracked by a limited number of sensors in short observation windows. This research examines the use of a new class of multitarget filters to approach the problem of orbit determination for the large number of objects present. The filters make use of a recently developed mathematical toolbox derived from point process theory known as Finite Set Statistics (FISST). Details of implementing FISST-derived filters are discussed, and a qualitative and quantitative comparison between FISST and traditional multitarget estimators demonstrates the suitability of the new methods for space object estimation. Specific challenges in the areas of sensor allocation and initial orbit determination are addressed in the framework. The sensor allocation scheme makes use of information gain functionals as formulated for FISST to efficiently collect measurements on the full multitarget system. Results from a simulated network of three ground stations tracking a large catalog of geosynchronous objects demonstrate improved performance as compared to simpler, non-information theoretic tasking schemes. Further studies incorporate an initial orbit determination technique to initiate new tracks in the multitarget filter. Together with a sensor allocation scheme designed to search for new targets and maintain knowledge of the existing catalog, the method comprises a solution to the search-detect-track problem. Simulation results for a single sensor case show that the problem can be solved for multiple objects with no a priori information, even in the presence of missed detections and false measurements. Collectively, this research seeks to advance the capabilities of FISST-derived filters for use in the estimation of geosynchronous space objects; additional directions for future research are presented in the conclusion. Advisors/Committee Members: Penina Axelrad, Brandon Jones, Jay McMahon, Nisar Ahmed, Gregory Beylkin.

Subjects/Keywords: Geosynchronous Orbit; Information Gain; Initial Orbit Determination; Multitarget Filtering; Random Finite Sets; Sensor Allocation; Aerospace Engineering

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APA (6^th Edition):

Gehly, S. (2016). Estimation of Geosynchronous Space Objects Using Finite Set Statistics Filtering Methods. (Doctoral Dissertation). University of Colorado. Retrieved from https://scholar.colorado.edu/asen_gradetds/148

Chicago Manual of Style (16^th Edition):

Gehly, Steven. “Estimation of Geosynchronous Space Objects Using Finite Set Statistics Filtering Methods.” 2016. Doctoral Dissertation, University of Colorado. Accessed March 04, 2021. https://scholar.colorado.edu/asen_gradetds/148.

MLA Handbook (7^th Edition):

Gehly, Steven. “Estimation of Geosynchronous Space Objects Using Finite Set Statistics Filtering Methods.” 2016. Web. 04 Mar 2021.

Vancouver:

Gehly S. Estimation of Geosynchronous Space Objects Using Finite Set Statistics Filtering Methods. [Internet] [Doctoral dissertation]. University of Colorado; 2016. [cited 2021 Mar 04]. Available from: https://scholar.colorado.edu/asen_gradetds/148.

Council of Science Editors:

Gehly S. Estimation of Geosynchronous Space Objects Using Finite Set Statistics Filtering Methods. [Doctoral Dissertation]. University of Colorado; 2016. Available from: https://scholar.colorado.edu/asen_gradetds/148

University of Colorado

4. Anderson, Paul Vincent. Characterizing Longitude-Dependent Orbital Debris Congestion in the Geosynchronous Orbit Regime.

Degree: PhD, Aerospace Engineering Sciences, 2015, University of Colorado

URL: https://scholar.colorado.edu/asen_gradetds/91

► The geosynchronous orbit (GEO) is a unique commodity of the satellite industry that is becoming increasingly contaminated with orbital debris, but is heavily populated… (more)

▼ The geosynchronous orbit (GEO) is a unique commodity of the satellite industry that is becoming increasingly contaminated with orbital debris, but is heavily populated with high-value assets from the civil, commercial, and defense sectors. The GEO arena is home to hundreds of communications, data transmission, and intelligence satellites collectively insured for an estimated 18.3 billion USD. As the lack of natural cleansing mechanisms at the GEO altitude renders the lifetimes of GEO debris essentially infinite, conjunction and risk assessment must be performed to safeguard operational assets from debris collisions. In this thesis, longitude-dependent debris congestion is characterized by predicting the number of near-miss events per day for every longitude slot at GEO, using custom debris propagation tools and a torus intersection metric. Near-miss events with the present-day debris population are assigned risk levels based on GEO-relative position and speed, and this risk information is used to prioritize the population for debris removal target selection. Long-term projections of debris growth under nominal launch traffic, mitigation practices, and fragmentation events are also discussed, and latitudinal synchronization of the GEO debris population is explained via node variations arising from luni-solar gravity. In addition to characterizing localized debris congestion in the GEO ring, this thesis further investigates the conjunction risk to operational satellites or debris removal systems applying low-thrust propulsion to raise orbit altitude at end-of-life to a super-synchronous disposal orbit. Conjunction risks as a function of thrust level, miss distance, longitude, and semi-major axis are evaluated, and a guidance method for evading conjuncting debris with continuous thrust by means of a thrust heading change via single-shooting is developed. Advisors/Committee Members: Hanspeter Schaub, Brandon Jones, Jeffrey Parker, Juan Restrepo, Darren McKnight.

Subjects/Keywords: active debris removal; geostationary orbit; geosynchronous orbit; orbital debris; Aerospace Engineering

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APA (6^th Edition):

Anderson, P. V. (2015). Characterizing Longitude-Dependent Orbital Debris Congestion in the Geosynchronous Orbit Regime. (Doctoral Dissertation). University of Colorado. Retrieved from https://scholar.colorado.edu/asen_gradetds/91

Chicago Manual of Style (16^th Edition):

Anderson, Paul Vincent. “Characterizing Longitude-Dependent Orbital Debris Congestion in the Geosynchronous Orbit Regime.” 2015. Doctoral Dissertation, University of Colorado. Accessed March 04, 2021. https://scholar.colorado.edu/asen_gradetds/91.

MLA Handbook (7^th Edition):

Anderson, Paul Vincent. “Characterizing Longitude-Dependent Orbital Debris Congestion in the Geosynchronous Orbit Regime.” 2015. Web. 04 Mar 2021.

Vancouver:

Anderson PV. Characterizing Longitude-Dependent Orbital Debris Congestion in the Geosynchronous Orbit Regime. [Internet] [Doctoral dissertation]. University of Colorado; 2015. [cited 2021 Mar 04]. Available from: https://scholar.colorado.edu/asen_gradetds/91.

Council of Science Editors:

Anderson PV. Characterizing Longitude-Dependent Orbital Debris Congestion in the Geosynchronous Orbit Regime. [Doctoral Dissertation]. University of Colorado; 2015. Available from: https://scholar.colorado.edu/asen_gradetds/91

University of Colorado

5. Stevenson, Daan. Remote Spacecraft Attitude Control by Coulomb Charging.

Degree: PhD, Aerospace Engineering Sciences, 2015, University of Colorado

URL: https://scholar.colorado.edu/asen_gradetds/94

► The possibility of inter-spacecraft collisions is a serious concern at Geosynchronous altitudes, where many high-value assets operate in proximity to countless debris objects whose… (more)

▼ The possibility of inter-spacecraft collisions is a serious concern at Geosynchronous altitudes, where many high-value assets operate in proximity to countless debris objects whose orbits experience no natural means of decay. The ability to rendezvous with these derelict satellites would enable active debris removal by servicing or repositioning missions, but docking procedures are generally inhibited by the large rotational momenta of uncontrolled satellites. Therefore, a contactless means of reducing the rotation rate of objects in the space environment is desired. This dissertation investigates the viability of Coulomb charging to achieve such remote spacecraft attitude control. If a servicing craft imposes absolute electric potentials on a nearby nonspherical debris object, it will impart electrostatic torques that can be used to gradually arrest the object's rotation. In order to simulate the relative motion of charged spacecraft with complex geometries, accurate but rapid knowledge of the Coulomb interactions is required. To this end, a new electrostatic force model called the Multi-Sphere Method (MSM) is developed. All aspects of the Coulomb de-spin concept are extensively analyzed and simulated using a system with simplified geometries and one dimensional rotation. First, appropriate control algorithms are developed to ensure that the nonlinear Coulomb torques arrest the rotation with guaranteed stability. Moreover, the complex interaction of the spacecraft with the plasma environment and charge control beams is modeled to determine what hardware requirements are necessary to achieve the desired electric potential levels. Lastly, the attitude dynamics and feedback control development is validated experimentally using a scaled down terrestrial testbed. High voltage power supplies control the potential on two nearby conductors, a stationary sphere and a freely rotating cylinder. The nonlinear feedback control algorithms developed above are implemented to achieve rotation rate and absolute attitude control. Collectively, these studies decisively validate the feasibility of Coulomb charging for remote spacecraft attitude control. Advisors/Committee Members: Hanspeter Schaub, Webster Cash, Brandon Jones, Daniel Moorer, Zoltan Sternovsky.

Subjects/Keywords: electrostatic modeling; high voltage experimentation; spacecraft attitude control; spacecraft charging; Multi-Vehicle Systems and Air Traffic Control; Navigation, Guidance, Control and Dynamics; Space Vehicles

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APA (6^th Edition):

Stevenson, D. (2015). Remote Spacecraft Attitude Control by Coulomb Charging. (Doctoral Dissertation). University of Colorado. Retrieved from https://scholar.colorado.edu/asen_gradetds/94

Chicago Manual of Style (16^th Edition):

Stevenson, Daan. “Remote Spacecraft Attitude Control by Coulomb Charging.” 2015. Doctoral Dissertation, University of Colorado. Accessed March 04, 2021. https://scholar.colorado.edu/asen_gradetds/94.

MLA Handbook (7^th Edition):

Stevenson, Daan. “Remote Spacecraft Attitude Control by Coulomb Charging.” 2015. Web. 04 Mar 2021.

Vancouver:

Stevenson D. Remote Spacecraft Attitude Control by Coulomb Charging. [Internet] [Doctoral dissertation]. University of Colorado; 2015. [cited 2021 Mar 04]. Available from: https://scholar.colorado.edu/asen_gradetds/94.

Council of Science Editors:

Stevenson D. Remote Spacecraft Attitude Control by Coulomb Charging. [Doctoral Dissertation]. University of Colorado; 2015. Available from: https://scholar.colorado.edu/asen_gradetds/94

University of Colorado

6. O'Keefe, Stephen Andrew. Autonomous Sun-Direction Estimation Using Partially Underdetermined Coarse Sun Sensor Configurations.

Degree: PhD, Aerospace Engineering Sciences, 2015, University of Colorado

URL: https://scholar.colorado.edu/asen_gradetds/95

► In recent years there has been a significant increase in interest in smaller satellites as lower cost alternatives to traditional satellites, particularly with the… (more)

▼ In recent years there has been a significant increase in interest in smaller satellites as lower cost alternatives to traditional satellites, particularly with the rise in popularity of the CubeSat. Due to stringent mass, size, and often budget constraints, these small satellites rely on making the most of inexpensive hardware components and sensors, such as coarse sun sensors (CSS) and magnetometers. More expensive high-accuracy sun sensors often combine multiple measurements, and use specialized electronics, to deterministically solve for the direction of the Sun. Alternatively, cosine-type CSS output a voltage relative to the input light and are attractive due to their very low cost, simplicity to manufacture, small size, and minimal power consumption. This research investigates using coarse sun sensors for performing robust attitude estimation in order to point a spacecraft at the Sun after deployment from a launch vehicle, or following a system fault. As an alternative to using a large number of sensors, this thesis explores sun-direction estimation techniques with low computational costs that function well with underdetermined sets of CSS. Single-point estimators are coupled with simultaneous nonlinear control to achieve sun-pointing within a small percentage of a single orbit despite the partially underdetermined nature of the sensor suite. Leveraging an extensive analysis of the sensor models involved, sequential filtering techniques are shown to be capable of estimating the sun-direction to within a few degrees, with no a priori attitude information and using only CSS, despite the significant noise and biases present in the system. Detailed numerical simulations are used to compare and contrast the performance of the five different estimation techniques, with and without rate gyro measurements, their sensitivity to rate gyro accuracy, and their computation time. One of the key concerns with reducing the number of CSS is sensor degradation and failure. In this thesis, a Modified Rodrigues Parameter based CSS calibration filter suitable for autonomous on-board operation is developed. The sensitivity of this method's accuracy to the available Earth albedo data is evaluated and compared to the required computational effort. The calibration filter is expanded to perform sensor fault detection, and promising results are shown for reduced resolution albedo models. All of the methods discussed provide alternative attitude, determination, and control system algorithms for small satellite missions looking to use inexpensive, small sensors due to size, power, or budget limitations. Advisors/Committee Members: Hanspeter Schaub, Penina Axelrad, Nikolaus Correll, Brandon Jones, Jay McMahon.

Subjects/Keywords: Coarse Sun Sensors; Sun-Direction Estimation; Underdetermined; CubeSat; small satellite; mission limitation; Multi-Vehicle Systems and Air Traffic Control; Systems Engineering and Multidisciplinary Design Optimization; The Sun and the Solar System

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APA (6^th Edition):

O'Keefe, S. A. (2015). Autonomous Sun-Direction Estimation Using Partially Underdetermined Coarse Sun Sensor Configurations. (Doctoral Dissertation). University of Colorado. Retrieved from https://scholar.colorado.edu/asen_gradetds/95

Chicago Manual of Style (16^th Edition):

O'Keefe, Stephen Andrew. “Autonomous Sun-Direction Estimation Using Partially Underdetermined Coarse Sun Sensor Configurations.” 2015. Doctoral Dissertation, University of Colorado. Accessed March 04, 2021. https://scholar.colorado.edu/asen_gradetds/95.

MLA Handbook (7^th Edition):

O'Keefe, Stephen Andrew. “Autonomous Sun-Direction Estimation Using Partially Underdetermined Coarse Sun Sensor Configurations.” 2015. Web. 04 Mar 2021.

Vancouver:

O'Keefe SA. Autonomous Sun-Direction Estimation Using Partially Underdetermined Coarse Sun Sensor Configurations. [Internet] [Doctoral dissertation]. University of Colorado; 2015. [cited 2021 Mar 04]. Available from: https://scholar.colorado.edu/asen_gradetds/95.

Council of Science Editors:

O'Keefe SA. Autonomous Sun-Direction Estimation Using Partially Underdetermined Coarse Sun Sensor Configurations. [Doctoral Dissertation]. University of Colorado; 2015. Available from: https://scholar.colorado.edu/asen_gradetds/95

University of Colorado

7. Chabot, Joshua A. A Spherical Magnetic Dipole Actuator for Spacecraft Attitude Control.

Degree: MS, Aerospace Engineering Sciences, 2015, University of Colorado

URL: https://scholar.colorado.edu/asen_gradetds/100

► Spacecraft generally require multiple attitude control devices to achieve full attitude actuation because of the limited control authority a single, traditional device can provide.… (more)

Subjects/Keywords: attitude control; magetic dipole; magnetic bearing; reaction sphere; spherical actuator; Navigation, Guidance, Control and Dynamics; Space Vehicles

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APA (6^th Edition):

Chabot, J. A. (2015). A Spherical Magnetic Dipole Actuator for Spacecraft Attitude Control. (Masters Thesis). University of Colorado. Retrieved from https://scholar.colorado.edu/asen_gradetds/100

Chicago Manual of Style (16^th Edition):

Chabot, Joshua A. “A Spherical Magnetic Dipole Actuator for Spacecraft Attitude Control.” 2015. Masters Thesis, University of Colorado. Accessed March 04, 2021. https://scholar.colorado.edu/asen_gradetds/100.

MLA Handbook (7^th Edition):

Chabot, Joshua A. “A Spherical Magnetic Dipole Actuator for Spacecraft Attitude Control.” 2015. Web. 04 Mar 2021.

Vancouver:

Chabot JA. A Spherical Magnetic Dipole Actuator for Spacecraft Attitude Control. [Internet] [Masters thesis]. University of Colorado; 2015. [cited 2021 Mar 04]. Available from: https://scholar.colorado.edu/asen_gradetds/100.

Council of Science Editors:

Chabot JA. A Spherical Magnetic Dipole Actuator for Spacecraft Attitude Control. [Masters Thesis]. University of Colorado; 2015. Available from: https://scholar.colorado.edu/asen_gradetds/100

University of Colorado

8. Peng, Ji. Uncertainty Quantification via Sparse Polynomial Chaos Expansion.

Degree: PhD, Mechanical Engineering, 2015, University of Colorado

URL: https://scholar.colorado.edu/mcen_gradetds/112

► Uncertainty quantification (UQ) is an emerging research area that aims to develop methods for accurate predictions of quantities of interest (QoI's) from complex engineering… (more)

▼ Uncertainty quantification (UQ) is an emerging research area that aims to develop methods for accurate predictions of quantities of interest (QoI's) from complex engineering systems, as well as quantitative validation of the associated mathematical models, with presence of random inputs. To perform a comprehensive UQ analysis, polynomial chaos expansion (PCE) is now a commonly used approach in which the QoI is represented in a series of multi-variate polynomials that are orthogonal with respect to the measure of the inputs. Traditional methods for PCE, such as Monte Carlo, stochastic collocation, least-squares regression, are known to suffer from either slow convergence rate or rapid growth of the computational cost (as the number of random inputs increases) in identifying the PCE coefficients. When the PCE coefficients are sparse, i.e., many of them are negligible, it has been shown that compressive sampling is an effective technique to identify the coefficients with smaller number of system simulations. In the context of compressive sampling, this thesis presents new approaches which improve the accuracy of identifying PCE coefficients, and therefore the PCE itself. In detail, a weighted L_1-minimization including a priori information about the PCE coefficients, a bi-fidelity L_1-minimization, a bi-fidelity orthogonal matching pursuit (OMP), and an L_1-minimization including the derivatives of QoI with respect to the random inputs are proposed. Both theoretical analyses and numerical experiments are presented to demonstrate that all the proposed approaches reduce the cost of computing a PCE. % We use various numerical experiments to show that all the proposed approaches improve the accuracy in PCE approximation. For a QoI whose PCE with respect to the measure of the underlying random inputs is not sparse, a polynomial basis design is proposed where, in addition to the coefficients, the basis functions are also learned from the simulation data. The approach has been empirically shown to find the optimal basis which makes the PCE converge more rapidly, and enhances the accuracy of the PCE approximation. Advisors/Committee Members: Alireza Doostan, Daven Henze, Brandon Jones, Kurt Maute, Oleg Vasilyev.

Subjects/Keywords: Basis design; Compressive sampling; Polynomial chaos expansion; Sparse approximation; Uncertainty quantification; Applied Mathematics; Mechanical Engineering; Statistics and Probability

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APA (6^th Edition):

Peng, J. (2015). Uncertainty Quantification via Sparse Polynomial Chaos Expansion. (Doctoral Dissertation). University of Colorado. Retrieved from https://scholar.colorado.edu/mcen_gradetds/112

Chicago Manual of Style (16^th Edition):

Peng, Ji. “Uncertainty Quantification via Sparse Polynomial Chaos Expansion.” 2015. Doctoral Dissertation, University of Colorado. Accessed March 04, 2021. https://scholar.colorado.edu/mcen_gradetds/112.

MLA Handbook (7^th Edition):

Peng, Ji. “Uncertainty Quantification via Sparse Polynomial Chaos Expansion.” 2015. Web. 04 Mar 2021.

Vancouver:

Peng J. Uncertainty Quantification via Sparse Polynomial Chaos Expansion. [Internet] [Doctoral dissertation]. University of Colorado; 2015. [cited 2021 Mar 04]. Available from: https://scholar.colorado.edu/mcen_gradetds/112.

Council of Science Editors:

Peng J. Uncertainty Quantification via Sparse Polynomial Chaos Expansion. [Doctoral Dissertation]. University of Colorado; 2015. Available from: https://scholar.colorado.edu/mcen_gradetds/112

University of Colorado

9. Jasper, Lee E.Z. Open-Loop Thrust Profile Development for Tethered Towing of Large Space Objects.

Degree: PhD, Aerospace Engineering Sciences, 2014, University of Colorado

URL: https://scholar.colorado.edu/asen_gradetds/82

► Towing objects in space has become an increasingly researched mission concept. Active debris removal, satellite servicing, and asteroid retrieval concepts in many cases rely… (more)

▼ Towing objects in space has become an increasingly researched mission concept. Active debris removal, satellite servicing, and asteroid retrieval concepts in many cases rely on a thrusting vehicle to redirect and steer a passive object. Focus is often placed on the method of attachment, considering techniques such as grappling or netting the passive object. However, the actual process of towing, once capture has occurred, has not yet received much attention. This research considers the process of towing in space with the tug and passive object attached by a tether. Tethers are not only an effective way of transmitting forces, but they are utilized on many of the towing concepts considered, especially in orbital debris removal. Because the two end bodies are tethered, there is a potential for collision after any maneuver. To avoid collisions, the maneuver, and therefore thrust profile, must be designed in such a way as to limit separation distance reduction between the end bodies. Open-loop input shaping techniques are developed and employed in order to control the flexible system in both deep space and on-orbit environments. To study the behavior, an active debris removal system is proposed as a case study. This system, called the tethered-tug, considers using the reserve fuel from a recently launched upper stage rocket to rendezvous with, capture, and tow a near-by debris object. The system’s performance is considered for five distinct open-loop thrust control profiles including on-off/step, frequency notched, discretized notch, Posicast, and bang-off-bang. Tether property variations are also considered along with off-axis towing, slack tethers, and debris with initial rotation rates. Input shaping is not only necessary but, it can be robust to unknown system properties while nearly zeroing relative motion between the end bodies. When considering on-orbit behavior specifically, the system settles into a tumbling or gravity gradient oscillation formation. This is highly advantageous because the orbital dynamics keep the end bodies separated. While the study focuses on the debris problem, conclusions from this dissertation are applicable to general tethered towing mission concepts. Advisors/Committee Members: Hanspeter Schaub, John K. Bennett, Brandon Jones, Jeffrey Parker, Daniel Scheeres.

Subjects/Keywords: active debris removal; input shaping; orbital debris; space tether; tethered towing; Aerospace Engineering

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APA (6^th Edition):

Jasper, L. E. Z. (2014). Open-Loop Thrust Profile Development for Tethered Towing of Large Space Objects. (Doctoral Dissertation). University of Colorado. Retrieved from https://scholar.colorado.edu/asen_gradetds/82

Chicago Manual of Style (16^th Edition):

Jasper, Lee E Z. “Open-Loop Thrust Profile Development for Tethered Towing of Large Space Objects.” 2014. Doctoral Dissertation, University of Colorado. Accessed March 04, 2021. https://scholar.colorado.edu/asen_gradetds/82.

MLA Handbook (7^th Edition):

Jasper, Lee E Z. “Open-Loop Thrust Profile Development for Tethered Towing of Large Space Objects.” 2014. Web. 04 Mar 2021.

Vancouver:

Jasper LEZ. Open-Loop Thrust Profile Development for Tethered Towing of Large Space Objects. [Internet] [Doctoral dissertation]. University of Colorado; 2014. [cited 2021 Mar 04]. Available from: https://scholar.colorado.edu/asen_gradetds/82.

Council of Science Editors:

Jasper LEZ. Open-Loop Thrust Profile Development for Tethered Towing of Large Space Objects. [Doctoral Dissertation]. University of Colorado; 2014. Available from: https://scholar.colorado.edu/asen_gradetds/82

University of Colorado

10. Lathrop, Brian Wesley. An Investigation of Alternate Transfer Strategies to the Sun-Earth Triangular Lagrangian Points.

Degree: PhD, Aerospace Engineering Sciences, 2014, University of Colorado

URL: https://scholar.colorado.edu/asen_gradetds/84

► Techniques for low energy transfers have been applied to constructing trajectories to various locations in the solar system. Previous techniques have concentrated on orbit… (more)

Subjects/Keywords: invariant manifolds; L4 L5; Lagrangian points; Low Energy Transfer; periodic orbits; three-body dynamics; Astrodynamics; Navigation, Guidance, Control and Dynamics

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Lathrop, B. W. (2014). An Investigation of Alternate Transfer Strategies to the Sun-Earth Triangular Lagrangian Points. (Doctoral Dissertation). University of Colorado. Retrieved from https://scholar.colorado.edu/asen_gradetds/84

Chicago Manual of Style (16^th Edition):

Lathrop, Brian Wesley. “An Investigation of Alternate Transfer Strategies to the Sun-Earth Triangular Lagrangian Points.” 2014. Doctoral Dissertation, University of Colorado. Accessed March 04, 2021. https://scholar.colorado.edu/asen_gradetds/84.

MLA Handbook (7^th Edition):

Lathrop, Brian Wesley. “An Investigation of Alternate Transfer Strategies to the Sun-Earth Triangular Lagrangian Points.” 2014. Web. 04 Mar 2021.

Vancouver:

Lathrop BW. An Investigation of Alternate Transfer Strategies to the Sun-Earth Triangular Lagrangian Points. [Internet] [Doctoral dissertation]. University of Colorado; 2014. [cited 2021 Mar 04]. Available from: https://scholar.colorado.edu/asen_gradetds/84.

Council of Science Editors:

Lathrop BW. An Investigation of Alternate Transfer Strategies to the Sun-Earth Triangular Lagrangian Points. [Doctoral Dissertation]. University of Colorado; 2014. Available from: https://scholar.colorado.edu/asen_gradetds/84

University of Colorado

11. Trowbridge, Michael Aaron. Autonomous 3D Model Generation of Orbital Debris using Point Cloud Sensors.

Degree: MS, Aerospace Engineering Sciences, 2014, University of Colorado

URL: https://scholar.colorado.edu/asen_gradetds/86

► A software prototype for autonomous 3D scanning of uncooperatively rotating orbital debris using a point cloud sensor is designed and tested. The software successfully… (more)

Subjects/Keywords: 3D scanning; explicit loop closure heuristic; Graph SLAM; model generation; orbital debris; point clouds; Aerospace Engineering; Artificial Intelligence and Robotics; Computer-Aided Engineering and Design; Systems Engineering and Multidisciplinary Design Optimization

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Trowbridge, M. A. (2014). Autonomous 3D Model Generation of Orbital Debris using Point Cloud Sensors. (Masters Thesis). University of Colorado. Retrieved from https://scholar.colorado.edu/asen_gradetds/86

Chicago Manual of Style (16^th Edition):

Trowbridge, Michael Aaron. “Autonomous 3D Model Generation of Orbital Debris using Point Cloud Sensors.” 2014. Masters Thesis, University of Colorado. Accessed March 04, 2021. https://scholar.colorado.edu/asen_gradetds/86.

MLA Handbook (7^th Edition):

Trowbridge, Michael Aaron. “Autonomous 3D Model Generation of Orbital Debris using Point Cloud Sensors.” 2014. Web. 04 Mar 2021.

Vancouver:

Trowbridge MA. Autonomous 3D Model Generation of Orbital Debris using Point Cloud Sensors. [Internet] [Masters thesis]. University of Colorado; 2014. [cited 2021 Mar 04]. Available from: https://scholar.colorado.edu/asen_gradetds/86.

Council of Science Editors:

Trowbridge MA. Autonomous 3D Model Generation of Orbital Debris using Point Cloud Sensors. [Masters Thesis]. University of Colorado; 2014. Available from: https://scholar.colorado.edu/asen_gradetds/86

University of Colorado

12. Anderson, Paul V. Characterizing Longitude-Dependent Orbital Debris Congestion in the Geosynchronous Orbit Regime.

Degree: PhD, Aerospace Engineering Sciences, 2010, University of Colorado

URL: https://scholar.colorado.edu/asen_gradetds/14

► The geosynchronous orbit (GEO) is a unique commodity of the satellite industry that is becoming increasingly contaminated with orbital debris, but is heavily populated… (more)

Subjects/Keywords: active debris removal; geostationary orbit; geosynchronous orbit; orbital debris; Aerospace Engineering

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Anderson, P. V. (2010). Characterizing Longitude-Dependent Orbital Debris Congestion in the Geosynchronous Orbit Regime. (Doctoral Dissertation). University of Colorado. Retrieved from https://scholar.colorado.edu/asen_gradetds/14

Chicago Manual of Style (16^th Edition):

Anderson, Paul V. “Characterizing Longitude-Dependent Orbital Debris Congestion in the Geosynchronous Orbit Regime.” 2010. Doctoral Dissertation, University of Colorado. Accessed March 04, 2021. https://scholar.colorado.edu/asen_gradetds/14.

MLA Handbook (7^th Edition):

Anderson, Paul V. “Characterizing Longitude-Dependent Orbital Debris Congestion in the Geosynchronous Orbit Regime.” 2010. Web. 04 Mar 2021.

Vancouver:

Anderson PV. Characterizing Longitude-Dependent Orbital Debris Congestion in the Geosynchronous Orbit Regime. [Internet] [Doctoral dissertation]. University of Colorado; 2010. [cited 2021 Mar 04]. Available from: https://scholar.colorado.edu/asen_gradetds/14.

Council of Science Editors:

Anderson PV. Characterizing Longitude-Dependent Orbital Debris Congestion in the Geosynchronous Orbit Regime. [Doctoral Dissertation]. University of Colorado; 2010. Available from: https://scholar.colorado.edu/asen_gradetds/14

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