Research On Guidance Law Of Air-based Missile For Boost Phase Interception

The air-based anti-boost phase missile can intercept ballistic missiles in the boost phase.It has the characteristics of flexible launch deployment,rapid response,and high combat efficiency.It is an important development direction for the missile defense system.However,in the process of interception guidance,there are many problems such as short available interception time,complex interception rendezvous scenes,variable acceleration of the target and uncertain trajectory.This article has conducted deep research on the rapid and precise guidance of air-based anti-boost missiles,focusing on the analysis of interception scenarios,rapid planning and tracking of intercept trajectories,online guidance law design,and terminal guidance law design.The main contents are as followsFirstly,modeling and analysis of the interception scenario of the air-based antiboost missile.The composition of the air-based anti-boost missile system,the interception process and the specific structure type of the interceptor are introduced.The dynamic model of the interceptor and the target is established separately.Combining the movement characteristics,a remote interception scenario of the booster segment is constructed,and the interception sequence and the characteristics are analyzed.According to the execution mode of guidance command and flight characteristics,the flight process of interceptor is divided into four stages: first stage boost phase,second stage boost phase,midcourse guidance phase and terminal guidance phase.In view of the characteristics of rapid response required for the boost phase interception,a rapid launch decision scheme is designed based on BP neural network and particle swarm optimization algorithm.It can calculate the launch data and intercept window quickly,and provide flight instructions for the boost phase after the launch of the interceptor.It also lays a foundation for trajectory planning and tracking control,and guidance law design in the following flight phase.There are many flight constraints and uncertain parameters in the second boost phase of interceptor.Based on the improved sequential convex optimization and model predictive control theory,a fast trajectory planning and tracking control method is designed.The trajectory planning problem is established by analyzing the flight scene and constraints of the secondary boost phase.The dynamic equation is transformed into the relation equation between the state change and the control change,which is used as the equality constraint to construct the convex optimization model.The sequence convex optimization method is used to obtain the flight command.In order to reduce the influence of the initial value on the solution results and avoid the infeasible phenomenon of the sub-problems,the original convex optimization problem is transformed into two sub-problems to be solved by designing the relaxation factor and the convergence process of the trust region,which can improve the convergence of the algorithm.When the flight process of the air-based anti-boost missile has the influence of deviation disturbance,the trajectory tracking method is designed by combining the proposed convex optimization model with model predictive control theory.The flight command can be solved quickly in a short prediction time domain,and stable tracking of the planned trajectory can be realized.In the midcourse guidance phase of interceptor,the uncertainty of target trajectory prediction will lead to the time-varying prediction intercept point.The interceptor needs to adjust the flight state according to the target change until the seeker captures the target.In this paper,a convex optimization method with dynamically adjustable discrete points and trust region is designed,and then a midcourse guidance scheme with online command modification is proposed.Firstly,a medium guidance model with time-varying prediction hit point and interception time is established.The target trajectory forecast information is introduced into the model,and the handover constraint conditions are converted into the optimization problem of the zero-control miss amount of the end flight,which is used as a constraint under the mid-guidance optimization framework.Then,the flight command optimization problem was established with the least energy consumption and the shortest flight time as cost function.Using pseudo-spectral discretization method and non-convex constraint conversion method to convert the original optimization problem into a convex optimization problem,the flight command can be solved.Considering the uncertainty of flight parameters and target trajectory prediction,based on the convex optimization model,the flight command is re-planned according to the current state of the interceptor and the target trajectory in each guidance cycle.Since it takes a certain amount of time to calculate the guidance command,it will delay the command on the interceptor.The command correction method is designed based on the nonlinear programming sensitivity analysis theory.At the same time,an adaptive adjustment strategy of trust region and discrete points is designed to improve the efficiency of online guidance instruction calculation and has the potential for real-time guidance applications.Considering the terminal guidance of air-based anti-boost missiles,a kinetic interceptor terminal guidance law suitable for the maneuvering targets is designed.A guidance model is established based on the relative motion relationship between the interceptor and the target in the line-of-sight rotating coordinate system.Through the interception conditions derived from the camouflage characteristics of the motion,the expression of the guidance command acting in the normal direction of the line of sight is derived.When the guidance thrust of the kinetic energy interceptor is limited,the PWPF regulator is used to adjust the guidance command.Considering the controllable conditions and interception conditions of the system,the regulator parameters are theoretically designed.Then,the interception performance of the motion camouflage terminal guidance law is analyzed theoretically based on the relative motion equation and interception conditions.According to the initial state of terminal guidance and the upper bound of target maneuver,the theoretical range of guidance coefficient and the angular rate of missile target line of sight rotation is given.Then,the range of guidance coefficient and the range of initial motion state of the interceptor,that is,the acquisition ability of the terminal guidance law,are derived when the interception conditions are satisfied.It can provide theoretical support for the selection of terminal guidance law coefficient and the judgment of interception ability.