This paper presents an adaptive fixed-time guidance law for the three-dimensional interception guidance problem with impact angle constraints and control input saturation against a maneuvering target. First, a coupled guidance model formulated by the relative motion equation is established. On this basis, a fixed-time disturbance observer is employed to estimate the lumped disturbances. With the help of this estimation technique, the adaptive fixed-time sliding mode guidance law is designed to accomplish accurate interception. The stability of the closed-loop guidance system is proven by the Lyapunov method. Simulation results of different scenarios are executed to validate the effectiveness and superiority of the proposed guidance law.
