Research On Information Processing In Asynchronous Interception Of Hypersonic Aircraft

In recent years, with the United States as an example, many countries have vigorously developed the near space hypersonic aircraft. With the characteristics of speed, range, maneuverability, survivability and load carrying, the hypersonic aircraft can perform air surveillance, or other combat support tasks, to national security has brought a huge threat. Therefore, it is of great significance to study its defense technology. The difficulty of intercepting an hypersonic target mainly lies in detecting inaccuracy:(1) affections from aerospace background electromagnetic waves, refraction and reflection;(2) affections on detection system from strong Interaction of the hypersonic target flying through the atmosphere. Meanwhile, The maneuvering overload of hypersonic target is generally small er than the interceptor, thus we assume that working out the detection inaccuracy problem by the cooperation of multiple kill vehicles plays a more important role in successful interception. Based on the desire of successful interception and cost savings, the separate interceptions in terms of time is proposed and studied. Main reserch includes the following aspects:Firstly, the scheme of separate interceptions is described and modeled. The relative motion equations are given after defining the relevant coordinate system. The contents and steps of the scheme are illustrated by the geometry of the three objects and the working sequence of the two interceptors. Formulas for information transmission are derived following. The whole process of the interception is divided into the ‘estimation period’ and the ‘forecast period’ in terms of the time, and the study will be carried out on these two segments respectively.Secondly, through the analysis of the motion characteristics of hypersonic vehicle, the reasonable tracking model is determined. Based on the results of the simulation which is led by widely consulting literature of hypersonic vehicle trajectory, the motion characteristics of the hypersonic flight is revealed and appropriate acceleration tracking model is chosen accordingly. Combining with the relative motion equations between missile and target, the model of tracking and estimation is obtained.Thirdly, this paper studied the ‘estimation period’. The task during this period is to obtain two interceptors’ relative motion information, so as to generate their guidance commands. In this paper, we put forward two methods of information acquisition, respectively based on the method for calculating the geometric and the method based on collaborative filtering. For the former, The influence of estimation error on the next interceptor’s guidance error during the information transmission is analyzed, helping gaining the estimation accuracy requirements. And in response to the estimation accuracy requirements, the guidance law which can improve the observability of relative motion information by active maneuvers is given. The effictiveness of the proposed guidance law is verified by simulations. For the latter, observability calculation shows that estimation of the second interceptor ’s guidance information is accurate and reliable. However, the tracking of the target is not as good as the former method.Finally, the ‘forecast period’ is studied, including trajectory forecast of the target, and the midcource guidance law design. Fitting of the filter result of the target acceleration from the ‘estimation period’ to forecast the future target acceleration, helps obtaining the forecast of target trajectory in ‘forecast period’. ‘Forecast by direct extrapolation’ and ‘forecast with the introduction of warning information’ are both presented and simulated. The former behaves effective in case of short-time forecast, while the latter behaves flexible in case o f long-time forecast. Guidance law based on the predictive interception point(PIP) is designed for the next interceptor’s midcourse. Simulation demonstrates that it is more suitable for ‘forecast with the introduction of warning information’. Comprehensive simulation about different forecast time range is conducted, according to which, the acceptable longest time range of forecast and the appropriate forecast method s and guidance laws for different-range forecasts are analyzed qualitatively.