Guidance law design against a ballistic target with multiple decoys: A finite time approach

In this paper, we consider a terminal interception engagement problem in which a flight vehicle intercepting a penetrating ballistic target accompanied with multiple decoys which appear as apparent targets. Due to the limitation of the maneuverability of the flight vehicle, these targets have to be taken into account before the the real target is identified. Otherwise, the interception of the real target maybe fails. First, we analyze the guidance course and obtain the equivalent constraints on the line-of-sight (LOS) angle rates to keep the targets within the reachable set of the intercepting flight vehicle, and this stage of the terminal guidance is called maintaining guidance. Next, the time during which the targets are reachable is calculated. Then, the guidance problem is converted into a Finite Time Stability (FTS) one, i.e. the stability of the LOS angle rates during the finite maintaining guidance time. The maintaining guidance command is designed via the linear state feedback controller design approach, by which the LOS angle rates remain within the bounded limit. Finally, numerical simulation is conducted and the results show the effectiveness of the proposed method.