Research On Guidance Strategy And Filtering Method For Tactical Ballistic Missile Interceptor

With the rapid development of the missile technology, our country has been threatened by the spread of the ballistic missiles, especially tactical ballistic missiles(TBM). Because of the high velocity and spiral maneuver of TBM during their reentry flight, the anti-missile system faces a big challenge. On the background of endoatmospheric TBM interceptor, some key technologies of guidance and filtering are discussed. The main contents of the dissertation are as follows:After comparing and demonstrating some representative modeling methods, the dissertation proposes an H∞guidance law and analyzes its performance under the modified polar coordinates. On the condition that the target escapes with the optimal strategy, analytical solutions of capture region, interception time and miss distance are demonstrated, and the concept of the capture region with acceleration limitation is proposed and analyzed, which reveals the relationship among the relative distance, the tangent velocity of line of sight (LOS), the normal velocity of LOS and the acceleration limitation.To avoid the influence of missile's dynamic feature, based on the precise motion model, an integrated guidance and control strategy is proposed, which considers the missile's guidance feature and control feature. Facing high maneuvering targets, the strategy can eliminate the negative effect of missile's dynamic characteristic, and get high precision even without control loop compensation. Then the influence of measurement accuracy is analyzed, and basing on the strategy's application, the solution is discussed.Then to reduce the measurement noise while intercepting TBM, some guidance laws and filtering algorithms are reached.To avoid the disturbance of airflow heat effect, the head-pursuit intercept method is introduced. To analyze the quality of this intercept method, a variable structure guidance is designed in which the normal velocity of LOS is chosen as the slide mode. Then the integrated guidance and control strategy mentioned in the previous section is redesign in the case of head-pursuit interception. The simulation results show the validity and superiority of these methods.According to the characteristics of ballistic missiles'spiral maneuver, based on the conical spiral coordinates, the quasi-cylinder coordinates are established, the target motion equations are deduced. A linear filter is designed based on the coordinates and motion equations, and the filter can effectively track the conical spiral or circular maneuvering targets without knowing their maneuver frequency. During the terminal guidance period, the line of sight rate measured by the seeker changes irregularly, so the EMD-KF filtering method is proposed. The method can filter nonlinear signals adaptively, and avoids the end effect of empirical mode decomposition (EMD) by using Kalman theory. Simulation results show that the proposed method exhibits good filtering performance for the line of sight rate.