Tracking And Intercept Guidance Methods Against Hypersonic Glide Targets

The Hypersonic glide target(HGT)breaks through the flight mode of the traditional ballistic target,which can glide in near space for a long time by virtue of an aerodynamic configuration with large lift-drag ratio.As one of the most threatening offensive weapons,it simultaneously possesses high velocity and strong maneuverability.How to intercept the HGT has been the research hotspot and frontier problem in the field of missile defense.Based on this background,this dissertation conducts research on target tracking and intercept guidance.First,in terms of the problem that modeling errors in a tracking model against HGT lead to low tracking precision,a robust nonlinear filtering algorithm is constructed based on the unscented Kalman filter(UKF)frame and used to estimate the motion state of HGT.The precision of target tracking is closely related to target tracking model and filtering estimation algorithm.In view of complex and various modes of HGT motion,it is difficult to establish a target motion model matching the real motion mode in real time.Then,the modeling error is generated.From a dynamic perspective,unknown aerodynamic accelerations are represented as generalized aerodynamic parameters which are assumed as Wiener processes.The parameters are augmented into the target motion equation and then estimated along with the kinematic state of target.The measurement model of ground-based radar is established.The strong tracking filtering theory and the Huber technique are embedded into the UKF frame,which are used to enhance the robustness to errors from state and measurement models respectively.In addition,the mutual interferences are suppressed between the two robust tools.Through Monte Carlo simulations,the robust nonlinear filtering algorithm can lower the state estimation error in the presence of model errors.Second,two tracking methods of adjusting maneuver-frequency are proposed based on interacting-multiple-model(IMM)and measurement innovation.The self-adaptation of maneuver-model parameter is employed to enhance the adaptation of tracking method to HGT complex and various motion modes.Several typical maneuver models are introduced.The aerodynamic acceleration of HGT is modeled as the Singer model.An IMM method is designed to adapt the critical maneuver-frequency parameter in the Singer model and extend the coverage of motion model.Another approach to adapting maneuver-frequency is proposed based on measurement innovation.According to the orthogonality principle,an adjustment factor that can reflect modeling errors to some extent is computed from measurement innovation to online adjust the maneuver-frequency in the Singer model.In terms of multiple patterns of HGT maneuver,the adaption of the above two approaches is verified by Monte Carlo simulations.The modeling error from a fixed model parameter is reduced and consequently the tracking precision is improved.However,the estimated precision of the measurement-innovation-based approach is superior to that of the IMM-based one,and the computation cost is lower.Third,in terms of the problem that the endoatmospheric interceptor has a disadvantage in speed over HGT,novel differential geometric guidance laws(DGGL)are put forward based on differential geometric theory,and can be applied to head-on intercept HGT inside the atmosphere.The differential geometric model of interceptor-target engagement is established in the interceptor arc system.An extended DGGL is derived composed of curvature and torsion commands with no assumptions on motion states of interceptor and target.The corresponding capture performance is analyzed and a sufficient condition is given.Based on the extended DGGL,a generalized DGGL is presented for secondary design which eliminates the complex computation of torsion and the information of target acceleration.The effectiveness of the novel DGGL to head-on intercept HGT is verified through simulating different engagement scenarios.Final,the generalized DGGL is combined with modern control approaches to suppress interceptor-target line-of-sight rotation resulting from HGT strong maneuver.Three guidance laws are designed and named as adaptive sliding-mode guidance law based on a rapid reaching law,adaptive integral sliding-mode guidance law with finite-time convergence,and path-tracking-based guidance law with finite-time convergence.To obtain the robustness to target maneuver and avoid command chattering,the sliding-mode-control method is adopted to track a predetermined sliding-mode surface,target maneuver is adaptively dealt with,and advanced intercept guidance laws are derived with different convergence characteristics.By intercepting HGTs with various maneuver patterns,simulations results indicate the three guidance laws can flexibly control the convergence of line-of-sight rate.The terminal miss distance is small,the guidance command is continuous,and an excellent tradeoff is made between robustness and chattering.Moreover,the laws possess certain robustness to measurement noises and are beneficial to be implemented in engineering.Clinging to the development frontier of missile defense,this dissertation enriches the idea and method of studying the problem of tracking and intercepting HGT.The research is able to provide theoretical support and solution reference for our country's technology development of defensing HGT.