Research On Transfer Alignment Technology Of Vehicle-borne Submunition On Moving Base

Ballistic missile carrier submunition warhead can effectively carry out long-range,large-area strikes.Due to the limitation of load-carrying capacity,the submunition usually carries inertial devices with smaller volume and lower precision,while the ammunition warhead has stronger load-carrying capacity and can carry larger and more precise inertial devices,so the inertial navigation accuracy of the submunition warhead is higher than that of the submunition warhead.The installation error angle of the shrapnel and the bullet is estimated by the difference of inertial navigation information between the shrapnel and the submunition.The attitude matrix of the shrapnel is modified by this angle,an d the low precision inertial navigation information of the submunition is approached to the high precision inertial navigation information of the shrapnel.This process is called transfer alignment.In the course of vehicle carrying submunition traveling to launch point,various random excitations will occur due to braking,road gradient and other reasons.In this paper,the dual-vector dynamic characteristics of these random excitations are tested,and then the transfer alignment model of different vehicle-borne inertial navigation systems for submunition inertial navigation is established,and the vehicle-borne inertial navigation system for submunition inertial navigation is aligned;then the submunition is erected separately.The transfer alignment of th e carrier missile inertial navigation system to the submunition inertial navigation system is carried out during the flight of the missile in the active phase.The multi-scheme transfer alignment process is used to reduce the missile's pre-firing preparation time and accurately estimate the installation error angle between the shrapnel and the bullet,so as to ensure that the bullet inertial navigation system has more accurate initial navigation information at the moment of separation of the shrapnel.Because of the information asynchrony of INS and other reasons,there are time delays between master and sub-inertial navigation data.This paper considers that the acceleration and angular velocity of the carrier are approximately unchanged in the delay time.A transfer alignment model based on time delay compensation is established to reduce the influence of time delay on transfer alignment and improve the accuracy of transfer alignment.There is a certain distance between the shrapnel and the bullet,and it is not rigid installation,which leads to the rod arm effect and elastic deformation between the shrapnel and the bullet.These factors are coupled to reduce the accuracy of transfer alignment.In this paper,the second-order Markov model is used to model the elastic deformation,and the elastic deformation and rod arm effect are compensated separately,then the coupling dynamic rod arm compensation is established.Compensation model is used to improve the final transfer alignment accuracy.The actual inertial navigation error model is a complex non-linear model,which requires the use of non-linear filters such as EKF and UKF for alignment,and these filters generally take a long time to calculate.The linearization of the model will result in truncation error,which makes the model deviate from reality and reduces the alignment accuracy.In this paper,a quadratic alignment method based on virtual rotation of coordinate axis is proposed.First,the first transfer alignment is carried out,then the coordinate axis of the bullet inertial navigation system is rotated virtual according to the estimated results of the first transfer alignment,and the second transfer alignment is carried out again.The quadratic alignment is compared with the non-linear UKF and CKF filtering algorithms.The results show that the secondary alignment can effectively improve the transfer alignment accuracy and reduce the alignment calculation time.