  We study a multi-body asset-guarding game in missile defense where teams of
interceptor missiles collaborate to defend a non-manuevering asset against a
group of threat missiles. We approach the problem in two steps. We first
formulate an assignment problem where we optimally assign subsets of
collaborating interceptors to each threat so that all threats are intercepted
as far away from the asset as possible. We assume that each interceptor is
controlled by a collaborative guidance law derived from linear quadratic
dynamic games. Our results include a 6-DOF simulation of a 5-interceptor versus
3-threat missile engagement where each agent is modeled as a missile airframe
controlled by an autopilot. Despite the assumption of linear dynamics in our
collaborative guidance law and the unmodeled dynamics in the simulation
environment (e.g., varying density and gravity), we show that the simulated
trajectories match well with those predicted by our approach. Furthermore, we
show that a more agile threat, with greater speed and acceleration, can be
intercepted by inferior interceptors when they collaborate. We believe the
concepts introduced in this paper may be applied in asymmetric missile defense
scenarios, including defense against advanced cruise missiles and hypersonic
vehicles.
