Airspace Anti-jamming Technology For Satellite Communication System

With the enhancement of jamming technology,the anti-jamming ability of satellite communication system has been challenged greatly.In order to ensure the reliability of satellite communication system,it is necessary to adopt more effective and robust antijamming measures.Traditional anti-jamming strategies mainly suppress or eliminate interference according to the characteristics of time-frequency domain.On the one hand,such anti-jamming measures need accurate interference detection and identification schemes,on the other hand,for some special interference,accurate anti-jamming cannot be carried out.Since the satellite communication system contains space information in the information transmission,this paper focuses on how to realize the effective antiinterference of the satellite communication system by combining the multi-domain information from the airspace.The main content of this thesis consists of four parts:The second chapter designs the spatial anti-jamming module of satellite communication system link.After analyzing the downlink structure of satellite communication system,different spatial anti-jamming models are designed.Firstly,the DOA estimation module combined with spatial anti-jamming structure is added to achieve effective spatial anti-jamming when there is no interference information,and then the space-time anti-jamming structure and space-frequency anti-jamming structure are proposed for the broadband satellite communication system.The third chapter studies the interference reconstruction algorithm based on DOA estimation.Among various effective airspace anti-jamming measures,adaptive beamforming technology is selected for airspace anti-jamming.On the premise of effective realization of interference DOA estimation,An LS algorithm based on interference vector reconstruction(LS-IVR)is proposed.Firstly,several interference reconstruction algorithms based on gradient search are described.Then the LS-IVR algorithm is proposed.The simulation results show that the traditional algorithm is not robust enough under different interference,but the LS-IVR algorithm can realize errorfree transmission in the rear system.The fourth chapter studies space-time adaptive beamforming algorithm based on LCMV criterion.Firstly,different types of space-time adaptive beamforming algorithms are studied.Then,a reduced rank space-time adaptive processing based on feature oblique projection(STAP-Fop)was proposed.The simulation results show that the proposed algorithm can realize error-free transmission in the rear system under three kinds of interference without increasing the consumption of computing resources,and the array gain can be maintained around 12 d B.The fifth chapter studies an adaptive air-frequency beamforming algorithm based on subband decomposition.Firstly,different types of air-frequency adaptive beamforming algorithms are studied.And then proposed space-frequency adaptive processing based on frequency-domain interference detection(SFAP-FID).Simulation results show that the proposed algorithm can reduce the computational complexity of antiinterference to an order of magnitude,and realize error-free transmission in the rear system under three kinds of interference.Compared with the STAP-Fop algorithm,the SFAP-FID algorithm has a slightly weaker anti-jamming ability,but it has the advantages of lower hardware requirements and low sensitivity to interference types.