Design of Fuzzy Logic Guidance Law Against High-Speed Target

Abstract

An advanced guidance law is developed against very high-speed targets. Preliminary studies have shown that the aspect angle of the interceptor at lock-on near 180 deg is a fundamental requirement for achieving small miss distance against a very high-speed target. To meet this requirement, a fuzzy guidance law in midcourse phase that is more similar to human decision making is designed. In terminal phase, a proportional and derivative-type fuzzy terminal guidance law is explored. It is shown that the integrated guidance scheme offers a near head-on homing condition before the missile enters terminal phase and provides better e nal results (smaller miss distance and wider defensible volume ) than the conventional guidance law. A complete simulation study is performed to show the effects of the proposed design. Nomenclature CD = drag coefe cient CD0 = zero drag coefe cient CL = lift coefe cient CLa = @CL/@a D = drag h = vertical coordinate L = lift m = mass Q = dynamic pressure Stref = reference area of ballistic target s = reference area T = thrust v = missile speed vt = target speed W = target weight x = horizontal coordinate a = angle of attack b = ballistic coefe cient c = e ight-path angle c t = reentry angle of target d = velocity angle error h = inertial line-of-sight angle l = induced drag coefe cient q = atmospheric density r = heading error angle