Research On Method And Simulation Of Line-of-sight Angular Rate Extraction For Strapdown Seeker

As an important part of low-cost missiles,the performance of strapdown seeker directly affects the hit accuracy and combat effectiveness of Self-homing missiles,and has a greater impact on the combat effectiveness of Self-homing guidance weapons,which has become a research hotspot of scholars all over the world.The strapdown seeker is directly connected with the missile.It can only directly output the line of sight angle,but can not output the angular rate information needed for guidance.Therefore,it is of great significance to study the angular rate extraction method based on the known information of strapdown seeker.In this paper,based on the application background of air defense missile,the method of extracting line-of-sight angular rate of strapdown seeker is studied,and the method of extracting line-of-sight angular rate is simulated and analyzed based on the process of interception and confrontation of air defense missile.In this paper,several main coordinate systems needed for modeling are defined and the transformation relations of coordinate systems are briefly introduced.On this basis,the missile dynamics and kinematics model,target model and proportional guidance model in the process of air defense missile interception and confrontation are constructed.The initial trajectory simulation parameters are set up,and the mathematical simulation under two scenarios of interception and confrontation is carried out.The trajectory simulation data of missile and target in the process of interception and confrontation are obtained.By analyzing the characteristics of strapdown seeker,it can be seen that strapdown seeker optical system is directly connected with missile,and a large number of ballistic attitude and motion information are coupled in the signal of strapdown seeker.The nonlinear characteristics of these information are obvious.In order to eliminate the coupling between strapdown seeker and missile attitude motion,a decoupling model of strapdown seeker’s line-of-sight angular rate is established.Nonlinear mathematical models such as state equation,measurement equation and noise model are established to extract strapdown seeker’s line-of-sight angular rate.It lays a foundation for the design of lineof-sight angular velocity extraction filter.In this paper,based on the extraction of line-of-sight angular rate,extended Kalman filter(EKF)algorithm and unscented Kalman filter(UKF)algorithm and Gauss integral particle filter algorithm are studied,and three algorithms are applied to the filter design in this paper.According to the established strapdown seeker line-of-sight angular rate extraction non-linear mathematical model,in four different interception confrontation scenarios,respectively,the output signal of strapdown seeker is filtered to complete the extraction of strapdown seeker line-of-sight angular rate,using MATLAB mathematical simulation to verify the effectiveness of the algorithm.The simulation results of three kinds of filtering algorithms are analyzed,and the causes of different accuracy of different motion conditions and different filtering algorithms under the same motion conditions are analyzed.