Integrated guidance and control with input saturation and disturbance observer

In presence of input saturation,a novel integrated guidance and control(IGC)law based on the backstepping technique is proposed for missiles attacking manoeuvring target in this paper.A modified saturation function and an auxiliary system are proposed to deal with the input saturation.The state of the auxiliary system is used in the IGC law design process and stability analysis.Considering the uncertainties caused by target manoeuvres,model errors and variation of the aerodynamic parameters,disturbance observers which converge in finite time are introduced to estimate and compensate them.Based on the Lyapunov theory,the detailed stability analysis of the closedloop system is presented.The non-linear numerical simulations are presented to illustrate the effectiveness of the proposed IGC law.