A computationally efficient, real-time trajectory optimization and guidance approach for hypersonic aircraft is described. The optimization approach is based on Euler-Lagrange energy state approximations. A three-dimensional, spherical-earth, aircraft-motion model with constraints on temperature, dynamic pressure, acceleration, and angle of attack is employed. Climb-to-orbit, return-from-orbit, flight-to-designated-landing-site, unpowered-abort, and powered-abort flight conditions are considered. Different performance criterion are used for different problems. Solution methods of varying computational complexity and performance capability are developed. An exact solution to the optimization problem using iteration on adjoint variables is developed. This method is the most exact but is not suitable for on-board processing. However, it serves as the basis of performance comparison for the approximate methods. Approximate solution methods suitable for onboard guidance are developed for the climb-to-orbit problem and the flight-to-a-landing site problem. A computationally efficient method for generating footprints is described. Footprints are used to determine when to start final descent and to identify candidate landing sites under an air-breathing-engine or rocket-engine abort or other emergency conditions. A hypersonic-vehicle guidance, navigation, and control configuration of the complete optimal guidance scheme is described. Sensitivity analysis results are included for climb-to-orbit trajectories. The probability of achieving orbit using the optimal guidance scheme and a stored nominal approach are compared.


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    Trajectory Optimization for Hypersonic Aircraft Guidance

    Schultz, R. L. / Hoffman, M. J. / Case, A. M. et al. | British Library Conference Proceedings | 1992


    Navigation, Guidance, and Trajectory Optimization for Hypersonic Vehicles

    R. L. Schultz / M. J. Hoffman / A. M. Case et al. | NTIS | 1990