Characteristic Model-Based Reentry Vehicle Guidance Law Design

A novel drag acceleration tracking guidance law is proposed for a hypersonic reentry vehiclewith high lift-drag ratio.By applying the characteristic model-based adaptive control method,a drag ac-celeration tracking guidance method is proposed together with a flight azimuth angle tracking used to mod-ify lateral distance.The characteristic model-based adaptive control method do not need the analyticalform of the aerodynamic lift and drag forces,which are often obtained by curve fitting of the trimmedflight data.This is especially advantageous when the reentry vehicle makes a flight through a large regimeand the aerodynamic parameters vary greatly.The flight azimuth angle tracking command is used to modi-fy the banking command,thus changing the lateral distance slightly without bank reversal.Six degree-of-freedom simulation results demonstrated that the guidance law proposed in this paper is effective but at thecost of the loss of total distance.