Nonlinear mapping based impact angle control guidance with seeker's field-of-view constraint

A novel nonlinear mapping based guidance strategy is proposed for attacking stationary and non-maneuvering moving targets with desired impact angle and seeker's field-of-view (FOV) constraints. In this paper, the impact angle is related with the line-of-sight (LOS) angle, and the seeker's FOV constraint is transformed to be the limit of the relative speed perpendicular to the LOS between missile and target. Firstly, the second-order nonlinear state equations of the guidance system are established, and backstepping control technique is used for the guidance commands design. The LOS angle is regulated in the first step by a bounded virtual guidance law designed based on hyperbolic tangent function. By introducing a one-to-one nonlinear mapping in the second step, the relative speed perpendicular to the LOS is controlled to track the virtual guidance law without exceeding the prescribed limit by a real guidance law. Then the stability of the closed loop system and the nonsingularity of the guidance commands are proved. Finally, the performances of the proposed guidance law are illustrated with numerical simulations. (C) 2019 Elsevier Masson SAS. All rights reserved.