Threats Assessment And Countermeasures Design On Approaching Spacecrafts

With the rapid development of space technology,outer space has gradually become a brand-new field essential to human life and development,but at the same time,the competition for limited space resources and favorable strategic positions have become increasingly fierce.Although the peaceful use of space is the mainstream of the times,military research on space has never stopped in countries such as the United States and Russia.Malicious approach behaviors of hostile aircraft approaching target aircraft for the purpose of limiting,disabling,seizing,paralyzing or countering the ability of target aircraft often occur.In order to improve the survivability of spacecraft facing malicious approach threats,this paper studies the maneuvering identification of non-cooperative spacecraft,the safety analysis of spacecraft facing approach threats and the countermeasures of spacecraft countering approach threats.The main research results of this paper are as follows:A maneuvering identification method for non-cooperative spacecraft with sparse orbit information is proposed.The orbital inversion model of spacecraft based on sparse orbital elements is established.Based on the orbital inversion,the optimization identification method of maneuvering parameters of spacecraft is proposed,and the optimization model of maneuvering parameters optimization identification is established.A double optimization algorithm of "global optimization and local correction" for solving the maneuvering parameter optimization model is proposed,which can improve the global search efficiency when using the high-precision orbit extrapolation model.Simulation results show that the proposed method can effectively identify the maneuvering parameters of non-cooperative aircraft under the condition of sparse orbit information.The safety analysis model of spacecraft facing approaching threat is established.The safety analysis flow of spacecraft facing approaching threat is put forward.The approach threat assessment method based on Multi Attribute Decision Making is proposed.The minimum relative distance,approach energy consumption and approach time are selected as the approach threat assessment indicators.The indicators are analyzed and standardized,and a multi-index approach threat assessment model for spacecraft is established.The simulation results show that the approach threat assessment method proposed in this paper can effectively assess the approach threat faced by spacecraft,and even if the tracker is on standby,the potential threat of the tracker can still be predicted by using this method.A tracker approach intention recognition method based on fuzzy recognition is proposed,and the indicators of fuzzy recognition are analyzed.The standardized fuzzy sets of four relative motion forms,i.e.rendezvous,flight around,skimming and hovering,are constructed,and the fuzzy recognition model of tracker approach intention is established.The simulation results show that the fuzzy recognition method proposed in this paper can effectively recognize the relative motion form of tracker approach,and on this basis,combined with prior information,the tracker approach intention can be judged.An anti-approach avoidance maneuver strategy considering maneuver window and relative navigation observability is proposed.Considering the energy consumption of tracker,the approach maneuvering window model based on the maneuvering reach domain of spacecraft is established.The relative navigation model with only-angle measurement is established,and on this basis,the measurement observability of tracker in relative navigation with only-angle measurement is defined.The active avoidance strategy of the target considering the maneuvering window and observability of the tracker is proposed.Simulation results show that the active avoidance strategy of the target proposed in this paper can effectively reduce the threat of the tracker.When the maximum avoidance maneuver of the target cannot completely eliminate the tracker approaching the maneuver window,it can reduce the relative navigation observability of the tracker while minimizing the tracker approaching the maneuver window,and improve the relative state estimation difficulty of the tracker.