A Nonlinear Suboptimal Guidance Law with 3D Impact Angle Constraints for Ground Targets

Abstract

Using the recently developed model predictive static programming (MPSP) technique, a suboptimal guidance law is presented in this paper considering the three-dimensional nonlinear engagement dynamics. The main feature of the guidance law is that it accurately satisfies terminal impact angle constraints in both azimuth as well as elevation, in addition to being capable of hitting the target with high accuracy. Moreover, it minimizes the control eort (i.e. the latax demand) throughout the engagement and hence leads to an optimal trajectory as well. The guidance law is primarily based on nonlinear optimal control theory and hence imbeds eective trajectory optimization concept into the guidance law. The performance of the proposed scheme is investigated using nonlinear simulation studies for stationary, moving and maneuvering ground targets, by considering both thrusted as well as unthrusted vehicles. Multiple munition engagement results are also presented to show the eectiveness of the proposed guidance scheme in such a scenario. A comparison plot for the Zero Eort Miss (ZEM) is also included, which reconfirms the superiority of the proposed optimal guidance over an augmented proportional navigation guidance available in the literature to engage maneuvering targets.