Missile Guidance System Design With Impact Angle Constriants

Missiles as precision-guided weapons have been widely applied in destructing important military targets in modern war. The missle's guidance ability which can decide the warhead whether attacked the targets precisely or not. So missile guidance system has been an important area of research in the past few decades. The main objective of a guided missile in terminal guidance process is to intercept the maneuverable target with zero miss distance and minimum effort consumption. In order to increase the lethality of warheads, guidance with impact angle constraints has become a necessity in most modern warfare.Now sliding mode control theory has widely appeared in the guidance law design,but traditional sliding mode control applied in guidance law design inevitableiy suffering from chattering, so we propose a Chattering free full-order sliding mode control used in the guidance accounting for first-order dynamics of missile autopilot and impact angle constraints.Using the Lyapunov stability theorem, it is proved that all signals in the closed loop system are ultimately bounded in finite time.Simulation comparision results demonstrate that the chattering free sliding mode control guidance law not only compensates the autopilot lag but also garantees the impact angle constaints with no chattering phenomenon.The classical missile guidance and control approaches treat the guidance and control systems as two separate processes. Although such approaches have been proven to be efficient for attacking the ground fixed targets and slowly constant velocity targets,but when the missile intercept the high maneuvering targets the cooperation between the two subsystems is hardly smooth with big miss distance. To overcome the shortcomings, the engineers proposed intergrated guidance and control algorithms designing the missile control systems.However, to the best of the knowledge of the authors, few attempts are made on IGC design for missiles with terminal impact angle constraints in the scenario intercept highly velocity maneuverable targets.So, in this paper we designed two guidance and control methods to solve the missle attacking maneuverable targets with impact angle constraints. The first method we use the Nonsingular terminal sliding mode and Dynamic surface control to deal with the mathematical model which we have builded about the missile dynamics and the kinematic engagement equations. As we known that the Sliding mode controller contains the switching functions compensating the uncertainty of nonlinear syetems of missile model which resulting in chattering phenomenon. The second method, we design the Reduced-order extended state observer (ESO) to estimate the uncertainties of guidance control loop. Based on the first method, we introduce the Reduced-order ESO into IGC design for the missle pursuing and attacking the evasive maneuverable targets with impact angle constraints. A comparision simulation among the two guidance and control law intercepting targets with sinusoidal acceleration show that the novel composite IGC law with ESO has obvious advantage in effort consumption and disturbance rejection performance.