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Full-Text Articles in Mechanical Engineering
Applications Of Relative Motion Models Using Curvilinear Coordinate Frames, Alex C. Perez
Applications Of Relative Motion Models Using Curvilinear Coordinate Frames, Alex C. Perez
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
A new angles-only initial relative orbit determination (IROD) algorithm is derived using three line-of-sight observations. This algorithm accomplishes this by taking a Singular Value Decomposition of a 6x6 matrix to arrive at an approximate initial relative orbit determination solution. This involves the approximate solution of 6 polynomial equations in 6 unknowns. An iterative improvement algorithm is also derived that provides the exact solution, to numerical precision, of the 6 polynomial equations in 6 unknowns. The initial relative orbit algorithm is also expanded for more than three line-of-sight observations with an iterative improvement algorithm for more than three line-of-sight observations. The …
Spacecraft Guidance Techniques For Maximizing Mission Success, Shane B. Robinson
Spacecraft Guidance Techniques For Maximizing Mission Success, Shane B. Robinson
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Traditional spacecraft guidance techniques have the objective of deterministically minimizing fuel consumption. These traditional approaches to guidance are developed independently of the navigation system, and without regard to stochastic effects. This work presents and demonstrates a new approach to guidance design. This new approach seeks to maximize the probability of mission success by minimizing the variance of trajectory dispersions subject to a fuel consumption constraint. The fuel consumption constraint is imposed by formulating the dynamics in terms of a steering command, and placing a constraint on the final time. Stochastic quadratic synthesis is then used to solve for the nominal …
Guidance And Navigation Linear Covariance Analysis For Lunar Powered Descent, Travis J. Moesser
Guidance And Navigation Linear Covariance Analysis For Lunar Powered Descent, Travis J. Moesser
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
A linear covariance analysis is conducted to assess closed-loop guidance, navigation, and control system (GN&C) performance of the Altair vehicle during lunar powered descent. Guidance algorithms designed for lunar landing are presented and incorporated into the closed-loop covariance equations. Navigation-based event triggering is also included in the covariance formulation to trigger maneuvers and control dispersions. Several navigation and guidance trade studies are presented demonstrating the influence of triggering and guidance and study parameters on the vehicle GN&C performance.