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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Huygens probe entry, descent, and landing trajectory reconstruction using the Program to Optimize Simulated Trajectories II

Striepe, Scott A. (Scott Allen), 1965- 29 August 2008 (has links)
The objectives of this research were to develop a reconstruction capability using the Program to Optimize Simulated Trajectories II (POST2), apply this capability to reconstruct the Huygens Titan probe entry, descent, and landing (EDL) trajectory, evaluate the newly developed POST2 reconstruction module, analyze the reconstructed trajectory, and assess the pre-flight simulation models used for Huygens EDL simulation. An extended Kalman filter (EKF) module was developed and integrated into POST2 to enable trajectory reconstruction (especially when using POST2-based mission specific simulations). Several validation cases, ranging from a single, constant parameter estimate to multivariable estimation cases similar to an actual mission flight, were executed to test the POST2 reconstruction module. Trajectory reconstruction of the Huygens entry probe at Titan was accomplished using accelerometer measurements taken during flight to adjust an estimated state (e.g., position, velocity, parachute drag, wind velocity, etc.) in a POST2-based simulation developed to support EDL analyses and design prior to entry. Although the main emphasis of the trajectory reconstruction was to evaluate models used in the NASA pre-entry trajectory simulation, the resulting reconstructed trajectory was also assessed to provide an independent evaluation of the ESA result. Major findings from this analysis include: Altitude profiles from this analysis agree well with other NASA and ESA results but not with Radar data, whereas a scale factor of about 0.93 would bring the radar measurements into compliance with these results; entry capsule aerodynamics predictions (axial component only) were well within 3-[sigma] bounds established pre-flight for most of the entry when compared to reconstructed values; Main parachute drag of 9% to 19% above ESA model was determined from the reconstructed trajectory; based on the tilt sensor and accelerometer data, the conclusion from this assessment was that the probe was tilted about 10 degrees during the Drogue parachute phase.
12

TRANSFORMATIONS AND DISCONTINUITIES FOR OPTIMAL SPACE TRAJECTORIES

Mason, Joseph D. January 1968 (has links)
No description available.
13

A study of a first perturbation solution to the equations of motion of a freely falling missile

Ronn, Benjamin 12 1900 (has links)
No description available.
14

A study of analyticity requirements on Regge singularities.

Haddad, Lewis Marlin. January 1970 (has links)
No description available.
15

Optimization of low-thrust spacecraft trajectories by direct shooting methods.

Rampersad, Christopher. January 2004 (has links)
Thesis (M.A. Sc.)--University of Toronto, 2004. / Adviser: Chris J. Damaren.
16

An extension of the quantum theory of scattering to the non-asymptotic regime using Bohmian trajectories /

Stenson, Jared R., January 1900 (has links)
Thesis (Ph. D.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 126-129). Also available on the World Wide Web.
17

Spacecraft guidance strategies for proximity maneurvering and close approach with a tumbling object

Boyarko, George A. January 2010 (has links) (PDF)
Dissertation (Ph.D. in Astronautical Engineering)--Naval Postgraduate School, March 2010. / Dissertation supervisor: Romano, Marcello. "March 2010." Description based on title screen as viewed on April 30, 2010. Author(s) subject terms: spacecraft proximity operations, Inverse Dynamics in the Virtual Domain, rapid-trajectory generation, spacecraft rendezvous, spacecraft docking, autonomous assembly, Pontryagin, Minimum Principle, GPOPS, optimal reorientation, optimal rendezvous, quaternion, polynomial. Includes bibliographical references (p. 193-197). Also available in print.
18

Regge pole analysis of pseudoscalar mesonbaryon inelastic scattering reactions

Sarma, Kuruganti Veera Lakshmana, January 1968 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1968. / Vita. Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.
19

Regge poles in boson-fermion scattering

Freedman, Daniel Z. January 1964 (has links)
Thesis (Ph. D.)--University of Wisconsin, 1964. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Bibliography: leaves 131-135.
20

TRAJECTORY PLANNING WITH DYNAMICS-AWARE PARABOLIC BLENDS

Unknown Date (has links)
This thesis presents the concept of dynamics-aware parabolic blends for an unmanned surface vehicle. Typically, trajectory generation techniques consider only kinematic constraints on a vehicle. By transforming the equations of motion for a surface vehicle to the body fixed frame, the dynamical constraints on the system are more intuitively integrated into the trajectory generator, when compared to working in the Earth fixed frame. Additionally, the accelerations, velocities, and positions generated by the parabolic blend algorithm are incorporated into the dynamic equations of motion for the vehicle to provide the feedforward control input of a two degree of freedom control law. The feedback control input of the two degree of freedom scheme is an integral sliding mode control law, which tracks the error between the vehicle state and the desired states generated by the novel parabolic blend technique. The approach is numerically validated through simulation, where the described control law demonstrates a 71.93% reduction in error when compared to a standard proportional-derivative control law subjected to the same desired trajectory. Furthermore, on water experiments were performed using both a proportional-derivative control law and an integral sliding mode control law. Both showed the ability to track the proposed parabolic blend approach. / Includes bibliography. / Dissertation (PhD)--Florida Atlantic University, 2021. / FAU Electronic Theses and Dissertations Collection

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