Terminal Guidance Law Based on Proportional Navigation

Introduction A TOPIC of classical interest in atmospheric flight dynamics of a landing aircraft or lifting-body vehicle is the synthesis of flight path from an arbitrary initial point to a terminal point with a desired final velocity vector direction. This problem has been extensively analyzed in the published literature.1−3 In a sense, similar problems can be considered for a mobile body such as an automobile, mobile robot, floating point, etc. Proportional navigation is a well-known homing interception guidance law4−6 for which the velocity vector (heading) of the interceptor is turned at a rate proportional with a navigation ratio λ to the rotation rate of the line joining the interceptor and moving target, which is the line of sight. As a rule, for the intercept trajectories the navigation ratio is held fixed. It is evident that the proportional navigation is acceptable for the nonmoving targets. In this case, the navigation ratio can be considered as a control variable, which depends on the current and desired final states. This Note presents a terminal guidance law to find a vehicle trajectory with the specified heading at the desired final point.