Optimal intercept guidance for short-range tactical missiles

Introduction IVTISSILE dynamic time lags, guidance command satura1? JL tion, and target acceleration are major factors contributing to excessive terminal miss distances resulting from shortrange intercept trajectories. The objective of this Technical Note is to describe a linear closed loop guidance law which compensates for these factors. Optimal control theory is utilized where the missile dynamics, represented as a single time lag, and target acceleration are defined in the constraint equations. A quadratic performance index is employed which implicitly effects a soft limit on the acceleration command. A zero terminal miss distance is the only boundary constraint imposed on the problem. The final form of the guidance law which includes a time varying navigation gain represents an extension of the guidance laws discussed by Bryson, Garber, and Abzug and is applicable to short range air-to-ground and air-to-air interception.