Nonlinear optimal tracking for missile gimbaled seeker using finite-horizon state dependent Riccati equation

The majority of homing guided missiles, uses gimbaled seekers. The equations describing seeker gimbal system are highly nonlinear. Accurate nonlinear control of the motion of the gimbaled seeker through the attached DC motors is required. In this paper, an online technique for finite-horizon nonlinear tracking problems using Finite-Horizon State Dependent Riccati Equation (SDRE) is presented. The idea of the proposed technique is the change of variables that converts the nonlinear differential Riccati equation to a linear Lyapunov differential equation. The proposed technique is effective for a wide range of operating points. Simulation results for a realistic gimbaled system are given to illustrate the effectiveness of the proposed technique.