Research And Implementation Of Anti-jamming Null Broadening Technology Based On Digital Multi-beam

With the rapid development of global satellite navigation system(GNSS),robust beamforming algorithm has gradually become a hot topic in high dynamic environment.When intended receivers move at high speed,the directions of arrival(DOA)corresponding to interferences may change rapidly in a small range.Howerver,the anti-jamming null which generated by conventional beamforming algorithm is very narrow,when the update speed of weight vector lags behind the change speed of interference,interference will be removed from the null range which will cause a performance degradation of array antenna.Therefore,it is of great important significance to study robust beamforming algorithm in high dynamic environment.This dissertation mainly studies the DOA estimation algorithm and null broadening algorithm in the process of robust beamforming,and analyzes their anti-jamming performance combined with digital multi-beam algorithm.1)In order to simulate the real array signal,this dissertation first establishes the spatial signal model based on the common arrays such as square array and uniform circular array,and deduces the array manifold of arbitrary planar array.Then,studies on the adaptive beamforming algorithm based on digital multi-beam.2)Aiming at the problem that some beamforming algorithms need the direction of signal and the number of sources,this dissertation studies the common DOA estimation algorithms such as multiple signal classification algorithm(MUSIC)and estimating signal parameters via rotational invariance techniques(ESPRIT).Then,studies the source number estimation algorithm based on information theory.After that,this dissertation proposed a fast source number estimation algorithm which used subspace analysis,because it avoids the proess of eigenvalue decompositon,so it can further improve the calculation speed.3)Aiming at the interference suppress problem of fast motion interference in high dynamic environment,this dissertation introduces some domestic and foreign latest research achievements of null broadening algorithms.On this basis,firstly,this dissertation proposed a null broadening algorithm based on Laplace distribution.This algorithm can not only effectively solve the problem of shallow null depth of conventional covariance matrix taper algorithms,but also can be applied to any planar array.Secondly,proposed a novel null broadening algorithm which used power estimation.Compared with the existing robust beamforming method,this algorithm has the best anti-jamming performance.4)In order to meet the requirements of fast and robust beamforming algorithm in engineering,firstly,this dissertation uses the combination of Laplace null broadening algorithm and power inversion(PI)algorithm to design the hardware implementation scheme,that will be based on ZYNQ hardware platform.Then,introduces the key module design of matrix inversion,matrix eigenvalue decomposition,matrix multiplication and other core modules in the algorithm process.Finally,verifies the correctness of the scheme through simulation test.