Hybrid Re-entry Guidance for Reusable Launch Vehicle

Abstract

A hybrid re-entry guidance approach, based on the nominal trajectory guidance method and predictor-corrector guidance, is proposed for the reusable launch vehicle (RLV). This approach generates a feasible re-entry trajectory which consists ofpre-entry phase, optimized bank angle phase and predictor-corrector phase. With the help of quasi-equilibrium glide condition (QEGC), the angle's constraints are transformed from re-entry constraints in optimized bank angle phase, and then guidance command is optimized using sequential quadratic program (SQP).In predictor-corrector phase, downrange errors are repeatedly calculated to updateconstant bank angle profiles.A bank reversal strategy based upon an azimuth error deadbandis designed to control crossrange. Simulationswith nominal and dispersion conditions demonstrategood performance of the guidance method.