Accession Number : AD0710325

Title :   SUB-OPTIMAL CORRECTION OF SPACECRAFT TRAJECTORIES.

Descriptive Note : Doctoral thesis,

Corporate Author : NEW YORK UNIV BRONX SCHOOL OF ENGINEERING AND SCIENCE

Personal Author(s) : Parkins,George

Report Date : JUN 1968

Pagination or Media Count : 87

Abstract : The problem considered is the minimum-fuel correction of spacecraft trajectories. The presence of a nominal trajectory during the midcourse phase is exploited to represent the system by a set of linear, time-dependent, ordinary differential equations. The control is assumed to be constrained in magnitude. Both measurement and execution errors are assumed to be present so that the resulting problem is stochastic. By an application of Decision Theory, an open-loop, fuel-optimal control is derived which is continuous in nature and dependent only on the solution of a deterministic version of the problem. A sub-optimal approximation, which is on-off in nature, is presented. The sub-optimal open loop control also depends only on the solution of a deterministic version of the problem, and in addition, provides a separation property whereby the estimator and the controller can be optimized separately. In the noiseless case, the sub-optimal control reduces to the optimal deterministic control. (Author)

Descriptors :   (*MANNED SPACECRAFT, MIDCOURSE GUIDANCE), (*MIDCOURSE GUIDANCE, CORRECTIONS), ITERATIONS, BOUNDARY VALUE PROBLEMS, DECISION THEORY, STOCHASTIC PROCESSES, CONTROLLABLE-THRUST ROCKET MOTORS, FUEL CONSUMPTION, ERRORS, NUMERICAL ANALYSIS, THESES

Subject Categories : Spacecraft Trajectories and Reentry

Distribution Statement : APPROVED FOR PUBLIC RELEASE