Research On Compensation Methods For Radome Error Slope Of Missile Seeker

In modern or future warfare,the model of war has gradually changed from the suppression of the firepower to the precision strike of the target.Therefore,precision guided weapons play an increasingly important role.As part of the precision guided weapon,the missile has indispensable in the modern war.This paper uses a self-seeking missile containing a radar seeker as the background.The radar seeker can track the target and provide the necessary information for the missile guidance system.In order to ensure that the missile's internal seeker antenna can work normally in high-speed airflow,the top of the missile is equipped with a streamlined radome.Theoretically,the radar seeker can receive all external electromagnetic signals to update guidance information.However,due to the influence of the shape and material of the radome,the electromagnetic signal will undergo refraction and reflection during the course of passing through the radome,which will seriously affect the measurement accuracy of the seeker,causing it to point to a false target,resulting in a LOS error.This error varies with the incident angle of the electromagnetic signal.This rate of change is called the slope of the radome sighting error.Therefore,estimating the radome error slope and compensating it has important significance for improving the guidance accuracy of the missile.Firstly,a qualitative analysis of the influence of the radome error on the missile guidance system was made,and the reasons for the accuracy of the guidance sys tem were theoretically analyzed,the radome error slope introduces a new attitude angle in the guidance system,producing a seeker-elastic body coupling loop,which greatly reduces the stability margin of missile guidance loops which affects the guidance accuracy and even the stability of the system.By establishing the nonlinear system mathematical model and analyzing the nonlinear observability,this system can satisfy the weak and obscure of the nonlinear system.The slope of the radome error can be estimated by filtering.Secondly,the radome error slope should be estimated.Since the model's state equation is linear,yet the observation equation is nonlinear.Therefore,this paper designs two different nonlinear filtering methods based on Extended Kalma n Filter(EKF)and Unscented Kalman Filter(UKF)respectively to estimate the radome error slope.According to the digital simulation,both the EKF and UKF methods can effectively estimate the error slope.We can see that compared to the extended Kalman filter,the estimation effect of the untracked Kalman filter is more accurate and faster.Finally,the compensation scheme of the radome error slope is designed,and the estimation results obtained by extended Kalman filter and untracked Kalman filter are substituted into the guidance system for compensation.And through the comparison of digital simulations,it can be seen that the miss distance after compensation is significantly reduced,explains that the compensation scheme is effective.The radome error slope estimated by the EKF and UKF methods can significantly improve the accuracy of missile guidance.