Analysis of optimal midcourse guidance law

An optimal midcourse guidance law is presented that maximizes the final speed for missiles against a target at far distance or at low attitude in which the final speed is a prime factor. An explicit acceleration command is derived analytically in which the trajectory-dependent optimal control gains are written in terns of thrust, lift, drag, and intercept boundary condition. The optimal guidance law can be implemented either in airframe coordinates or inertia coordinates. It is shown that the acceleration commands with constant control gain are adequate when the range is relatively short; during midcourse guidance, however, the optimal control gains are required to enhance the performance.