A Simplified Midcourse Guidance Law for Air Interceptors

In this paper, a class of simplified midcourse guidance laws is introduced for atmospheric interceptors. This type of guidance uses an additional flight path angle with respect to generalized collision course for the first stage of flight. The additional flight path angle is converted to a variable bias for the interceptor-target line-ofsight angular velocity. The original guidance scheme needs inertial measurement unit and command update for the midcourse phase, but the simplest form of the proposed guidance uses only line-of-sight angular velocity. Also, a vertical gyro reference is needed to separate the vertical and azimuth acceleration command. In the case in which the closing velocity is measured onboard, the guidance algorithm is improved. Therefore, the implementation of this guidance strategy is simple, even for available interceptors as an upgrade kit.