Quasi-optimum proportional navigation

The problem of deriving feedback guidance laws for interceptor type aerodynamically controlled missiles which seek to engage moving targets is considered. These missiles contain target trackers which provide angular information about the relative interceptor-to-target geometry. The performance criterion for this problem is quadratic, but the system equations are nonlinear. Suitable guidance mechanizations are obtained by applying the technique of quasi-optimum control. The efficiency of the resulting guidance system, relative to a linear optimum guidance system and a proportional navigation system, is demonstrated by simulations of attack situations in which the interceptor missile launch conditions depart from the nominal attack geometry.