ABSTRACT
The classical approach to missile guidance is usually based on applying a guidance law obtained from certain line-of-sight (LOS) geometrical rules. The guidance law is the algorithm by which the desired geometrical rule is implemented. According to the well-known proportional navigation (PN) law, widely used in military applications, the missile acceleration is proportional to the measured LOS rate. However, acting as the commanded missile acceleration, this law produces the missile real acceleration, which differs from the desired commanded acceleration. Usually, kinematics of PN are analyzed without taking into account missile dynamics, and most recommendations concerning guidance law parameters are made based on this analysis. In the previous chapters, we acted the same way. As shown in Chapter 4 [see equation (4.6)], the miss distance due to a step target maneuver is exactly zero for an idealized linearized inertialess two-dimensional PN missile-target engagement model. The inœuence of missile dynamics was examined analytically for single-lag models of guidance systems by using the method of adjoints [see equation (4.22)]. As indicated, the singlelag models, as well as the binomial models, do not quite match reality and do not accurately reœect œight control system dynamics. The analytical approach to analysis of effectiveness of PN for more realistic models of guidance systems, reœecting airframe and autopilot dynamics against weaving targets was considered in Chapter 5.
