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Optimal Guidance of Low-Thrust Interplanetary Space Vehicles


Ash, Gerald Richard (1969) Optimal Guidance of Low-Thrust Interplanetary Space Vehicles. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/RDY0-PH47.


The low-thrust guidance problem is defined as the minimum terminal variance (MTV) control of a space vehicle subjected to random perturbations of its trajectory. To accomplish this control task, only bounded thrust level and thrust angle deviations are allowed, and these must be calculated based solely on the information gained from noisy, partial observations of the state. In order to establish the validity of various approximations, the problem is first investigated under the idealized conditions of perfect state information and negligible dynamic errors. To check each approximate model, an algorithm is developed to facilitate the computation of the open loop trajectories for the nonlinear bang-bang system. Using the results of this phase in conjunction with the Ornstein-Uhlenbeck process as a model for the random inputs to the system, the MTV guidance problem is reformulated as a stochastic, bang-bang, optimal control problem. Since a complete analytic solution seems to be unattainable, asymptotic solutions are developed by numerical methods. However, it is shown analytically that a Kalman filter in cascade with an appropriate nonlinear MTV controller is an optimal configuration. The resulting system is simulated using the Monte Carlo technique and is compared to other guidance schemes of current interest.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:(Electrical Engineering and Mathematics) ; Optimal Control; Optimization; Space vehicle guidance; Ion Engine; Low Thrust Guidance
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Electrical Engineering
Minor Option:Mathematics
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Sridhar, Rangasami
Thesis Committee:
  • Unknown, Unknown
Defense Date:14 October 1968
Record Number:CaltechTHESIS:02192014-095711728
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:8085
Deposited By: Benjamin Perez
Deposited On:19 Feb 2014 19:17
Last Modified:25 Apr 2024 20:17

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