Researches On Guidance Laws For Intercepting Large Maneuvering Targets

The environment for intercepting missiles in the contemporary wars has becomeincreasingly complex，and the targets become more and more diverse. Such changes putforward higher requirements for the performance of the interceptor missiles. Proportionalnavigation law has been proven that it was a performance guidance law after decades ofPractice. But it is mainly applied to intercept none maneuvering or small maneuvering targets.When it is used for intercepting targets with strong mobility, its efficiency decreased.Therefore, this article has been studied new guidance laws with superior performance andsuitability.This paper analyzed the performance of existed guidance laws, referred to the researchesof new control technology applying on Guidance Law, studied the principle of guidance lawfor intercepting maneuvering targets, and then designed guidance laws based on the newcontrol technologies. First, according to the characteristics of the application of the moderninterceptor missiles on intercepting maneuvering targets, and variable structure control theory,designed the sliding mode variable structure guidance law. And then it smoothed the guidancelaw with switch parts. Simulated and compared with proportional navigation guidance law.Simulation results showed that performances of the sliding mode variable structure guidancelaw for intercepting large maneuvering targets are better. However, due to inertia of thesystem and the selecting of guidance law parameters, Sliding mode variable structureguidance law in some cases will cause a more serious jitter of line of sight angular rate, whichis detrimental to the guidance performance.In order to obtain guidance laws with better performances. This paper studied the adaptive sliding mode fuzzy guidance law which based on fuzzy control technology andvariable structure control technology. Fuzzy control rules expresses by analytic equations inthis paper, range of parameter-adaptive in analytical equations is determined by simulationand curve fitting. Accelerations of the targets are estimated by state reconstruction method.Finally, simulated with the adaptive sliding mode fuzzy guidance law, the sliding modevariable structure guidance law and proportional navigation method and then compared withthem every. Simulation results showed that when use Adaptive Fuzzy Guidance Law tointercept a variety of maneuvering targets, the intercept ballistic is the straightest, neededacceleration is the smallest, and its performance is the best of the three.