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Master's Projects

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Start date: 2010 × End date: 2019 × search.filters.applied.f.advisor: Holzinger, Marcus J. ×

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Now showing 1 - 7 of 7
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    A scalable hardware-in-the-Loop simulation for satellite constellations and other multi-agent networks
    (Georgia Institute of Technology, 2018-05-01) DeGraw, Christopher F.
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    Space Object Detection in Images Using Matched Filter Bank and Bayesian Update
    (Georgia Institute of Technology, 2015-12-11) Murphy, Timothy S.
    Electro-optical sensors, when used to track space objects, are often used to produce detections for some orbit determination scheme. Instead, this paper proposes a series of methods to use electro-optical images directly in orbit determination. This work uses the SNR optimal image filter, called a matched filter, to search for partially known space objects. By defining a metric for measuring matched filter template similarity, a bank of matched filters is efficiently defined by partitioning the prior knowledge set. Once partitioned sets are known, the matched filter bank can be localized to regions of the sky. A method for hypothesis testing the result of a matched filter for a space object is developed. Finally, a framework for orbit determination based on the matched filter result is developed. Simulation shows that the analytic results enable a better framework for implementing matched filters for low SNR object detection
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    Multi-Objective CubeSat Constellation Optimization for Space Situational Awareness
    (Georgia Institute of Technology, 2015-12-01) Snow, Adam C.
    The proliferation of on-orbit debris has motivated much of the recent space situ ational awareness (SSA) missions and related research. Space-based missions are typically carried out by large spacecraft, yet the emerging and improving technol ogy for CubeSat class satellites offers a potential new platform for SSA. This paper presents the graduate Special Problem effort to develop explore the optimization of a CubeSat constellation for SSA. This optimization approach considers two ob jectives: to maximize the number of daily unique detections while minimizing the lifecycle cost of a constellation. The epsilon constraint method is used to devel op the Pareto Frontier with a genetic algorithm as the single-objective optimizer. This work was prepared as part of a larger effort for the Journal of Spacecraft and Rockets, and the supporting material is included.
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    Use of Uninformative Priors to Initialize State Estimation for Dynamical Systems
    (Georgia Institute of Technology, 2015-12-01) Worthy, Johnny L., III
    The admissible region must be expressed probabilistically in order to be used in Bayesian estimation schemes. When treated as a probability density function (PDF), a uniform admissible region can be shown to have non uniform probability density after a transformation. This paper uses the fundamental multivariate probability transformation theorem to show that regardless of which state space an admissible region is expressed in, the probability density must remain uniform. The admissible region is shown to be a special case of the Jeffreys’ prior, an uninformative prior with a probability density that remains constant under reparameterization. This paper introduces requirements on how these uninformative priors may be transformed and used for state estimation.
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    Control Cost and Mahalanobis Distance Binary Hypothesis Testing for Spacecraft Maneuver Detection
    (Georgia Institute of Technology, 2015-11-12) Jaunzemis, Adris D.
    An anomaly hypothesis testing technique using the minimum-fuel control distance metric is extended to incorporate non-Gaussian boundary condition uncertainties and employ binary hypothesis testing. The adjusted control distance metric utilizes Gaussian mixtures to model non-Gaussian boundary conditions, and binary hypothesis testing allows inclusion of anomaly detection thresholds and allow able error rates. An analogous framework accommodating Gaussian mixtures and binary hypothesis testing is developed. Both algorithms are compared using simulated and empirical satellite maneu ver data. The North-South station-keeping scenario shows control distance to be less sensitive with increased uncertainty than Mahalanobis distance but more consistent with respect to observation gap duration, a trend which is corroborated using available real-world data. The same consistency with respect to observation gap is observed in East-West station-keeping while also showing control distance metric to be more sensitive for shorter observation gaps. In the non-Gaussian boundary con dition case, control distance outperforms Mahalanobis distance in both detection and computational complexity.
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    Coding Framework and Implementation for Resident Space Object Observation
    (Georgia Institute of Technology, 2015-05-01) Tyman, Nicole M.
    The detection, classification, and tracking of Earth-orbiting space objects is of great importance for the safety of orbiting spacecraft, motivating the improvement of the current space situational awareness (SSA) model. A revolutionary concept for SSA introduced by DARPA includes allowing independent observers to contribute observational data in order to reduce cost and introduce more space object data for the SSN. With the installment of a Raven-class telescope at the Georgia Institute of Technology, this report seeks to provide a coding framework for observations that allows for relevent contributions to the SSA concept. The information and coding architecture are illustrated, and the coding performance is analyzed. Improvements to the current architecture are introduced as future work.
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    Solar Sail Equilibria with Albedo Radiation Pressure in the Circular Restricted Three Body Problem
    (Georgia Institute of Technology, 2015-01-05) Grotte, Mariusz E.
    In this paper the albedo radiation pressure (ARP) is investigated in the circular restricted three body problem (CR3BP) for a system consisting of the Sun, a minor body and a solar sail. The analytical framework is provided with extension to the solar radiation pressure (SRP) theory. The minor body is treated as Lambertian with bidirectional reflectance distribution function (BRDF) for approximation purposes. In this study it is found that ARP dominates SRP in a volume around the minor body which extends to L1 and L2, characterized as the region of influence (RoI) with an analytically defined boundary. Numerical simulations show that the inclusion of albedo effects generates new locations of artificial equilibrium points nearby the minor body, an important fact to address for solar sail missions to asteroids and comets. Local stability and controllability at equilibrium points are investigated and the system is found to be unstable but controllable in general when solar sail attitude angles are chosen as control inputs. Furthermore, equilibrium points along the RoI boundary are found to be Lyapunov stable.