Terminal Time and Angle-constrained Interception of a Non-Maneuvering Target Under Autopilot Lag

This paper presents a guidance strategy for a pursuer, which is constrained to intercept a non-maneuvering target at a fixed set of terminal time and angle. The proposed method diverges from traditional methods in the sense that an explicit computation or estimation of time-to-go is unnecessary. Instead, we ensure that the relevant states of the pursuer-target engagement are brought to and maintained on a sliding manifold within a finite time. We further relax the assumption that the inner control loop is arbitrarily fast and account for the control loop dynamics by approximating it as a lower-order rational transfer function. The proposed design is completely nonlinear to allow for wide launch envelops and engagements commencing far from the collision course. We provide simulations to attest to the efficacy of the proposed approach.