Research On Guidance Algorithm Of Full Strap-down Guidance System

With the development of guidance technology,precision guided weapons have gradually become the main attack means of modern warfare due to the characteristics of high precision and high performance.The full strap-down guidance system has the advantages of low manufacturing cost,high guiding precision,and simple structure,thus become the key object of research in the research process of modern weapon systems.This paper takes the full strap-down guidance system as the research object.The research content mainly includes three parts: middle guidance algorithm design based on strap-down inertial navigation information,terminal guidance information estimation for the full strap-down seeker and the terminal guidance law design.In the study of missile attacking ground,it was found that the yaw motion and the tilt motion have a greater coupling effect,while the pitch angle and the trajectory inclination angle of the missile are larger in the conventional horizontal reference coordinate system.When the missile hits the target vertically,the missile loses a degree of freedom due to the yaw angle coincides with the roll angle.And there will be an unbounded quantity in the equation of missile attitude motion,so it is impossible to simulate the vertical attack trajectory.In order to solve these two problems,this paper introduces the oblique reference coordinate system,and designs the SINS method based on the oblique reference coordinate system.Then,according to the navigation solution data in the oblique reference coordinate system,the research of the midcourse guidance algorithm based on strap-down inertial navigation information is studied.Secondly,the full strap-down seeker is completely fixed on the missile body and can only sense the target line of sight information based on the missile body coordinate system,which cannot be directly applied to the terminal guidance law design.Therefore,this paper establishes the nonlinear mathematical model of the inertial line-of-sight angular velocity in the missile terminal guidance section.The extended Kalman filter algorithm and the unscented Kalman filter algorithm are applied respectively to filter the terminal guidance information.Through mathematical simulation,the filtering effects of the two filtering algorithms are verified and compared.Finally,in order to improve the guidance accuracy of the missile terminal guidance section,the guidance information of the full strap-down seeker is combined with the SINS solution information to conduct compound guidance in the terminal guidance section.And the optimal guidance law and the sliding mode variable structure guidance law with terminal angle constraints are designed.The mathematical simulation of the terminal guidance algorithm under different oblique angles is performed to compare the guidance effects of the two terminal guidance laws in the missile terminal guidance section.And the superiority of the oblique reference coordinate system in the study of the full strapdown guidance system is verified under the condition of large angle attack.