Profile-tracking-based gain-varying backstepping guidance law for maneuvering target interception with input saturation

In this paper, a profile-tracking-based gain-varying backstepping guidance law is developed to address the impact angle constrained guidance issue for the maneuvering target with input saturation. A new range-elapsed-based polynomial function is formulated as the reference line-of-sight angle profile to guide the missile to intercept the target with a specified angle. The profile can be analytically determined without tedious numerical optimization. Then, a novel gain-varying finite-time constrained backstepping guidance law is developed for tracking the designed profile. The tracking-error-based varying gain is designed to counteract the disturbance effects of target maneuvers. The stability of the closed-loop system is theoretically guaranteed. Finally, comparative simulations verify the effectiveness and advantages of the proposed method.