A New Composite Proportional Navigation Entry Guidance Strategy for Glider Under Multiple Uncertainties

This work presents a high precision entry guidance strategy for the glider subject to uncertainties in both aerodynamic parameters and atmospheric density. A new composite proportional navigation combined with disturbance observer is proposed to improve the precision of entry guidance. Firstly, the multiple uncertainties are analyzed and a dynamic model with uncertainties is established where the multiple uncertainties have been transformed into equivalent disturbances. Secondly, a disturbance observer is designed to estimate and compensate the equivalent disturbances. Meanwhile, a proportional navigation law is designed to guide the glider without considering the effect of uncertainties. Stability analysis are given to guarantee the closed-loop performance. Simulation results of X-33 model show the effectiveness and performance of composite proportional navigation entry guidance strategy for glider.