TABLE OF CONTENTS This chapter presents a discussion and overview of missile guidance and control laws as well as the basic equations that are used in intercepting a given target. Theoretically, the missile target dynamics are highly nonlinear. This is due to the fact that the equations of motion are best described in an inertial coordinate system, whereas aerodynamic forces and moments are conveniently represented in the missile and target body axis system. In addition, and if optimal control theory is used to model and/or formulate the plant (or system), unmodeled dynamics or parametric perturbations usually remain in the plant modeling procedure. Furthermore, speed plays an important role in determining interceptor missile aerodynamic maneuverability. Two basic guidance concepts will be discussed: (a) the homing guidance system, which guides the interceptor missile to the target by means of a target seeker and an onboard computer; homing guidance can be modeled as active, semiactive, and passive; and (b) command guidance, which relies on missile guidance commands calculated at the ground launching (controlling) site and transmitted to the missile. In addition to these guidance systems, two other forms of missile guidance have been used in the past or are being used presently: (a) inertial guidance (used mostly in ballistic missiles, and which will be discussed in detail in a later chapter), and (b) position-fixing guidance. Some guided missiles may contain combinations of the above systems. One such missile, the Bomarc (developed in the 1950s), had a command guidance system...
