Accession Number:

ADA416545

Title:

Aerocapture Guidance Methods for High Energy Trajectories

Descriptive Note:

Master's thesis

Corporate Author:

AIR FORCE INST OF TECH WRIGHT-PATTERSONAFB OH

Personal Author(s):

Report Date:

2003-05-23

Pagination or Media Count:

149.0

Abstract:

This thesis investigates enhancements of an existing numerical predictor-corrector aerocapture guidance algorithm PredGuid. The study includes implementation of an energy management phase prior to targeting with a generic method of transition and replacement of heuristic features with more generic features. The vehicle response during energy management was modeled as a second-order springmassdamper system. Phase change occurred when two conditions were met First, the vehicle could fly a constant bank angle of 1100 for the remainder of the trajectory and have the resulting apogee below or within a given tolerance above the target apogee. Second, the predicted final energy indicated that the vehicle would be on an elliptical, not hyperbolic, trajectory. So as to incorporate generic features, modeling of a separate lift down phase was replaced by using a lift-down condition to determine phase change and biasing to the same lift- down condition during targeting. Also, use of a heuristic sensitivity to calculate the first corrected bank angle was replaced by a simple smart guessing algorithm. Finally, heuristic lateral corridor boundaries were replaced by boundaries based on percentage of forward velocity.

Subject Categories:

  • Numerical Mathematics
  • Guided Missile Trajectories, Accuracy and Ballistics
  • Target Direction, Range and Position Finding

Distribution Statement:

APPROVED FOR PUBLIC RELEASE