A computationally efficient, real time trajectory optimization and guidance approach for hypersonic aircraft is described. The optimization algorithms compute, in-flight, minimum fuel trajectories within constraints from the current aircraft position to its final destination. In-flight trajectory computation can provide a high degree of vehicle autonomy which could greatly reduce aircraft ground support costs. The optimization approach is based on Euler-Lagrange theory and energy state approximations. A 3-D, spherical earth, aircraft motion model, with constraints on temperature, dynamic pressure and stall, is used. An exact optimal iterative solution and an approx. closed form feedback solution method are developed. In the exact approach, solutions are computed by iteration on adjoint constants. Each iteration requires a complete forward trajectory integration. In the approx. closed form feedback approach, the adjoint constants are expressed in terms of the states. No forward trajectory calculations are required, thus, the computations are minimal. Minimum fuel climb to orbit, powered abort, and unpowered abort trajectories are computed with both methods. The approx. closed form feedback solution closely matches the optimal iterative solution. A computationally efficient method for generating unpowered descent footprints is also described. Footprints are used to identify candidate landing sites under an engine failure or other emergency conditions, and to initiate final descent. A hypersonic vehicle guidance, navigation, and control configuration using the optimal closed form feedback guidance and the footprint generator is described.
Navigation, Guidance, and Trajectory Optimization for Hypersonic Vehicles
1990
22 pages
Report
Keine Angabe
Englisch
Spacecraft Trajectories & Flight Mechanics , Air Transportation , Aircraft configurations , Aircraft guidance , Hypersonic aircraft , Trajectory optimization , Air navigation , Aircraft models , Iterative solution , Aerodynamic stalling , Aircraft design , Algorithms , Cost reduction , Engine failure , Euler-lagrange equation , Fuel consumption , Real time operation , Trajectory control
Trajectory Optimization for Hypersonic Aircraft Guidance
British Library Conference Proceedings | 1992
|Trajectory Optimization for Hypersonic Aircraft Guidance
NTIS | 1992
|