Research On The Methods To Realize Space-Time Anti-Jamming In Satellite Navigation

With the Beidou-navigation service devices is increasingly developed,its location and communication services have been widely used in various fields.The existence of various interferences not only threaten the positioning accuracy of the system,but also limit the applied range of satellite navigation equipment severely.So it is urgent to study navigation anti-jamming technology.Space-time adaptive anti-jamming technology has become the focus of navigation anti-jamming because of its multi-domain combination advantage.The traditional space-time anti-jamming method not only has the disadvantages of too much computation due to too many dimensions,but also has the problem of main lobe deformity caused by signal and interference coming too close.Therefore,based on the above two points,this paper studies the improvement and implementation of anti-jamming algorithm for satellite navigation.The main contents are as follows:Firstly,starting at the structure of navigation receiver,the composition of satellite signals and the classification of interferences are analyzed,and under the two-dimensional surface array model,the spatial estimation of interferences,including the estimation of the number and the azimuth of interferences,is mainly introduced.Firstly,the number of narrowband and broadband interferences in space is estimated by MDL and AIC correctly.Then,the direction of interferences are identified by two-dimensional MUSIC and two-dimensional ESPRIT algorithm accurately.Finally,the simulation verifies the accuracy of space quantity and azimuth estimation under multiple interference sources,which provides prior knowledge for the anti-interference processing.Then,on the one hand,in order to solve the problem of increasing computation amount due to the increase of dimension in space-time processing,the GSC structure is introduced to realize space-time anti-interference.Using the dimensionality reduction function of blocking matrix in GSC structure,this paper provides a method of constructing GSC blocking matrix with PM propagator,namely PM-GSC.Compared with the traditional algorithm,the new algorithm not only overcomes the problem of high algorithm complexity caused by eigenvalue decomposition or singular value decomposition,but also improves the efficiency of the algorithm.On the other hand,in the scene where there are few visible satellites and the interference is too close to the desired satellite signal,a preprocessing blocking matrix is added before the ordinary GSC structure to filter out the adjacent interference components in the received signal in advance.Based on the above,this paper provided an improved PMGSC method,namely Imp-PM-GSC.The PM propagator method is used to construct the preprocessing blocking matrix and blocking matrix in the improved GSC structure.The new algorithm can not only promise the main lobe are well maintained and eliminate the suppression effect of neighboring interference,but also has an ideal output signal-to-noise ratio at low snapshot count,so it is suitable for engineering applications.Finally,based on the satellite navigation system,the hardware structure and chip selection of anti-jamming module are introduced in detail.Then,the multi-core DSP architecture design and parallel processing mechanism based on TMS3206678 development platform are discussed.Finally,using C language and DSP library function,the anti-jamming method of IMP-PM-GSC is realized efficiently.The results of digital source signal show that the algorithm is rationality,robust and practical.