Estimate Of Guidance Information For Strapdown Seeker And Design Of Integrated Guidance And Control Law

With the development of inertial devices and the advances in microprocessor technology,strapdown seeker and strapdown homing guidance technology have gradually been the concern of the world's military powers.Combining with the modern control theory and the characteristics of the strapdown system,the design concept of strapdown homing integrated guidance and control(IGC)has been developed.The strapdown seeker is an important part of the strapdown homing IGC missile.Firstly,some design specifications and technical problems to be solved are proposed for the strapdown seeker,and the working principles are described.Take a four-quadrant detector component type of And Differential circuit for example to note the measuring principle of laser seeker.Build a simplified model of the strapdown laser seeker when it is in a state of the Linear Tracking.In the case of the capture field of view for a strapdown seeker is not big enough,if there is an angle between the optical-axis of the seeker and the vertical-axis of the body artificially,defined as the pitching angle of optical-axis,it will be very helpful for detecting and capturing the target earlier,increasing the working time and distance of guidance,meanwhile improving the accuracy of hit.Aiming at solving the problem that the strapdown seeker cannot measure the line-of-sight(LOS)rate directly,a decoupling nonlinear guidance-information-estimated mathematical model of the strapdown seeker with a pitching angle of optical-axis was established.Three guidance-information-estimated methods respectively based on extended Kalman filter(EKF),unscented Kalman filter(UKF)and particle filter(PF)algorithms have been presented and simulated by MATLAB software.A hardware-in-the-loop simulation system was built up to provide the feasibility and effectiveness for engineering applications of a material strapdown laser seeker utilizing the UKF algorithm to estimate LOS rate.On the basis of the relationship between the dynamics and kinematics of missile,a six-degree-of-freedom nonlinear mathematical model of full state coupling was established.A longitudinal integrated guidance and control missile model has been obtained after simplifying.Based on the sliding-mode-variable-structure control theory,combining with the guidance information estimated by the strapdown seeker,aiming at solving the problem of difficulty in measuring the angle of attack in engineering implementation,an integrated guidance and control arithmetic of for engineering applications was developed.The feasibility of the proposed approach was verified by mathematic simulation.