Hybrid Guidance Algorithm using Flatness and Dynamic Inversion for RLV

A simplified guidance law suitable for onboard implementation is derived in this paper exploiting the flatness property of the translational dynamics of a reusable launch vehicle (RLV). A tracking law to follow a reference trajectory profile is formulated. Dynamic inversion helps cancel the undesired dynamics and replaces the inerent dynamics of the vehicle by desired dynamics. Simulation studies indicate the effectiveness of the tracking law in case of nominal and off-nominal conditions. The behaviour of the tracking law for perturbations in initial conditions, aerodynamic coefficients and for physical variations such as mass is analyzed.