Research On Interference Mitigation Technique Between LEO Satellite Constellation Systems

LEO satellite internet constellation system has the advantages of low communication delay and wide coverage,which has attracted domestic and foreign aerospace enterprises to deploy and launch LEO satellite constellation.The frequency used by different satellite constellation systems overlaps,resulting in harmful interference between satellite constellation systems.Therefore,it is urgent to study and develop technical methods that can mitigate the interference between LEO satellite internet constellation systems.Aiming at the problem of co-frequency interference between LEO satellite Internet constellation systems,this paper studies the complex interference scenarios,the interference mitigation techniques and interference evaluation methods between LEO satellite constellation systems.Then this paper puts forward two novel interference mitigation techniques,which are verified by simulation.Compared with the existing interference mitigation methods between LEO satellite internet constellation systems,the interference scenarios considered in this paper are more universal and comprehensive.In addition,the available time of the interfered earth station accounts for a higher proportion after using the proposed interference mitigation techniques.Therefore,the interference mitigation effect of the proposed interference mitigation techniques is better.The interference mitigation techniques proposed in this paper have certain guiding significance for the research of interference mitigation between LEO satellite constellation systems.The specific contents are as follows:1)An interference mitigation technique between LEO satellite internet constellation systems based on satellite antenna beam pointing optimization is proposed.The concept of dynamic exclusion zone of satellite antenna beam pointing is proposed for the first time,that is,the dynamic exclusion zone of satellite antenna beam pointing varies with the position of satellite on orbit.Then,considering the rapid change of link distance and link angle with time,the dynamic exclusion zone angle is optimized.The effectiveness of the proposed interference mitigation method is verified by selecting the system parameters of typical LEO satellite constellation.The simulation results show that the available time of the interfered system accounts for 98.5%after using the interference mitigation technique proposed in this paper.The proposed interference mitigation technique can effectively mitigate the harmful interference between LEO satellite constellation systems.2)An adaptive null interference mitigation technique based on cooperation and linear constraint minimum variance criterion is proposed.The interfering satellite accurately obtains the geographic location information of the interfered earth station through cooperation.Based on the linear constraint minimum variance beamforming criterion,the satellite antenna adaptively forms a main beam pointing to the communication earth station in the system according to the changes of the electromagnetic environment,and a null pointing to the interfered earth station.In addition,it transmits the signal with the minimum power.The working parameters of typical constellation systems are selected to verify the effectiveness of the proposed method.The simulation results show that the available time of the interfered system accounts for about 80%after using the proposed interference mitigation.The proposed interference mitigation method can effectively mitigate the harmful interference to the interfered system and improve the frequency compatibility between LEO satellite constellation systems.