| As one of the four largest global satellite navigation system,Compass ? satellite system can provide high-precision positioning and timing information in all-day and all-weather globally for users worldwide.It is widely used in national defense,earthquake relief,navigation,aviation and other fields.However,since navigation satellites are very far away the earth,and complex electromagnetic environment is existing during transmission,the power level of satellite navigation signals arriving at the earth recever is so low that satellite navigation receiver is vulnerable to various kinds of interference.So it has become an urgent problem of realizing real-time accurate navigation and positioning and improving the anti-interference ability of receiver for the users.The thesis focuses on Beidou navigation system and combined with Beidou navigation receiver signal processing project,this thesis realizes the design of three auxiliary channels' ASLC system and the system can suppress the broadband jamming signals which enter from antenna side-lobes.firstly,the thesis gives wideband ASLC and analyzes theory and derived formula based on sample matrix inversion(SMI)algorithm in detail.The selection of several methods for calculating the inversion of covariance matrix in weight computation is discussed and determine that Cholesky decomposition method can reduce the complexity of algorithm.Finally,the simulation model for the actual requirements is built,and interference signal of sampling Beidou satellite to act as the input signal,and ends up with the test results by processing of various modules of adaptive anti-jamming system.Simulation results show that the adaptive side-lobe cancellation system perform well in suppress active interference,and cancel ratio can reach 15 dB,and it can meet the design requirements.Besides,some mainly influencing factors are analyzed by simulation in detail,such as number of the interfering sources,interference intensity and delays. |
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