Optimal Missile Midcourse and Terminal Guidance and Control Law Design

This paper summarizes a combined midcourse and terminal guidance and control law design of missiles to achieve range enhancement and stability with excellent intercept performance. We derive analytic solutions of a closed loop, nonlinear optimal guidance law for three dimensional flight for both the midcourse and terminal phases. Since this combined guidance law contains the proportional navigation feature, it can quickly modify the missile trajectory in the case when the target position changes drastically during midcourse guidance. This results in zero heading error at handover from midcourse to terminal guidance. To design the autopilot for this missile, a unique modern autopilot synthesis technique is employed. The resulting guidance and control algorithm is sufficiently simple for onboard implementation and has been applied successfully for on-line operation. This has led to large overall performance improvement in missiles. Although a surface-to-air missile model is used in the guidance and control law design, analysis, and simulation, the guidance law can also be applied to surface-to-surface. air-to-air, and air-to-surface type missiles.