Optimal Midcourse Guidance Law with Flight Path Angle and Lead Angle Constraints to Reach Circular Target Area

An optimal midcourse guidance law with flight path angle and lead angle constraints to reach a circular target area is proposed here. In this paper, the circular target area is defined as a circle which center is a target to intercept and radius becomes a seeker's detection range. This guidance law is especially useful for a missile which has a strap-down type seeker with limited F.O.V. (Field Of View) because a missile's lock-on condition can be satisfied by imposing a final lead angle constraint with consideration of a seeker's F.O.V. limit. In addition, through a final flight path angle constraint, a missile can occupy an advantageous homing point. This guidance law is derived from an optimal control theory which minimizes a range weighted control energy and its characteristics are studied further. Finally, performance of this guidance law is verified by a numerical simulation.