Missile Guidance Law Design via μ-Synthesis

A new design method of a robust guidance law for missiles is presented. It has two features. One is that the guidance law is designed based on the heuristic idea that keeping the line-of-sight angular rate small can make the miss distance small. The other is that a linear robust control method, i.e., the μ-synthesis, is employed. When these are incorporated, uncertainties and disturbances in the homing system can explicitly be taken into account in the design to achieve the control or guidance objective. Specifically, the uncertainties and disturbances considered here include time delays in the missile dynamics, range variation between missile and target, measurement noise of the line-of-sight angular rate, and normal target acceleration. The guidance law obtained by this approach is a 4th order dynamic compensator requiring the line-of-sight angular rate as the only measurement. The miss distance is evaluated through nonlinear simulation. The simulation study shows that the proposed guidance law is generally superior to the proportional navigation guidance law and is also superior or equivalent to the suboptimal guidance law in miss distance.