Performance Analysis Of The Guidance Law For Missile Guidance System Based On Time-varying Model

Precision guided weapon represented by missile has been used widely inmodern high-tech wars. In order to pursue a higher precision of missile terminalguidance, people improve new guidance law constantly to meet the needs of morecomplex environment. At the same time, they try to analyze and evaluate theperformance of the existing terminal guidance system on combat missions. Thisthesis conducts research on the guidance law design and performance evaluation ofterminal guidance system.First, this paper established the coordinate systems which commonly used inthe process of the missile terminal guidance. The conversion relationship betweenthese coordinate systems is given also. The working principle of each subsystem inthe missile terminal guidance system is introduced in detail, such as seeker and itsnoise, controller and the guidance law, autopilot and play-mesh model of relativemovement. To get the linear time-varying model of missile terminal guidancesystem, the paper integrates and simplifies each subsystem based on the transferfunction of them. Depending on the characteristics of the missile terminal guidancesystem, this paper analysis the main points of guidance law design and thedifficulties of performance evaluation for terminal guidance system. This laid asound foundation for following research.Secondly, considering the missile may be face the faster maneuvering target.Based on the Lyapunov stability theory, a kind of extended proportional guidance law is designed;meanwhile, in the process of terminal guidance, a variable structure guidance law isdesigned. The extended proportional guidance has a easy form, and performances wellin attacting targets with a CA maneuvering; and the variable structure guidancelaw has stronger robustness for external disturbance and system parameterperturbation, therefore it still has well guidance accuracy when againstmaneuvering target.Finally, according to the general form of guidance law and using the methodof finite time norm, the paper estimates the effects of target maneuver and seekernoise on miss distance of terminal guidance system when parameters of autopilotsubsystem have different values. The quantitative relationship between the missdistance of missile and factors above-mentioned is summarized. The miss distanceof guidance system is evaluated in the case that seeker has a variety of input n oiseand target has escape maneuver. Based on the results of the assessment, the paperoptimizes some parameters of autopilot subsystem in specific tasks such as time constant and damping ratio.