Neoclassical Guidance for Homing Missiles

A new approach to guidance of homing missiles is considered. Like classical proportional navigation (PN), the new guidance law utilizes line-of-sight (LOS) rate measurement only. However, its performance is superior to PN, in the sense that zero-miss-distance (ZMD) is obtained against highly maneuvering targets. This merit is achieved with neither the estimation of target maneuver nor time to go. In the derivation of the new guidance law, a linearized formulation of the PN interception kinematics is used. Based on the method of adjoints, it is proved analytically that when the overall transfer function of the missile is biproper, that is, the degree of the numerator equals the degree of the denominator, ZMD is obtained. The ZMD property holds in the following cases: deterministic target maneuvers, random target maneuvers, deterministic target maneuvers with random starting times, fading noise, and passive- and active-receiver noise. The realization of the new guidance law requires lead compensation. When LOS rate measurement is corrupted by noise, lead-lag compensation can be used instead. These design considerations are illustrated in simulations, which verify that negligible miss distance against highly maneuvering targets is obtained even when the LOS rate measurement is noisy.