Research On Joint Anti-Jamming Algorithm Of Main And Side Lobe For Sparse Array

Modern radars work in a complex electromagnetic eviroment,and beamforming is more widely used in electronic warfare to improve the radar ability.For side lobe interference,various kinds of adaptive beamforming technologies can obtain good interference suppression effects.However,for main lobe interference,that is,when the interference enters from the main beam,the common adaptive methods will cause a deep zero point to be formed in the direction of the main lobe,shift the direction of the main beam,deform the main beam and significantly increase the side lobe level,which will affect the subsequent direction finding and tracking of the targets.If the radar seeker cannot effectively deal with these interferences,it will seriously damage the subsequent target detection and guidance functions.Therefore,modern electronic warfare puts forward higher requirements for adaptive beamforming,interference suppression capabilities,and target tracking capabilities.To the above problems,this thesis has a research on joint anti-jamming algorithm of main and side lobe for sparse array,the detail content can be seen as follows.First of all,the thesis introduces and simulates the traditional anti-main and side-lobe interference algorithms.For the side lobes interference,there are mainly conventional orthogonal projection algorithms,SMI algorithms,and multi-constrained LCMV algorithms and so on.The anti-main lobe algorithms mainly include the shaped main lobe interference suppression method,the BMP based on the preprocessing of the blocking matrix and the interference suppression conformal method based on the preprocessing of the characteristic matrix.However,the main lobe shaped LCMV can only solve the problem of the complete split of the main lobe,and still cause the main beam to be deformed.If the EMP and BMP do not use the shape-preserving strategy,the main lobe will also be offset.Secondly,this thesis introduces the basic principles of the four-channel anti-jamming algorithms.So four-channel GSC algorithms are used on sparse arrays,which can suppress the side-lobe interference,perform a shape-preserving of the main beam,and then use the four-channel method to suppress the main lobe interference.As a result,the angle discriminating curve is approximately the same as the static angle discriminating curve,and the angle measurement accuracy is fine.At the same time,a method of widening the zero notch and simultaneously resisting the interference of the main and side lobes is proposed,and good performances have been achieved.Finally,the performance of the four-channel method against main lobe interference is analysised,mainly the impact of amplitude and phase error on the four-channel interference suppression and angle measurement,the impact of amplitude and phase error on the main lobe offset,and the interference angle on the angle measurement error,And then the simulation conclusion can be drawn.According to the measured data,a suitable highprecision angle measurement method Capon algorithm is selected for direction finding.The tic-tac-toe array is divided into two sub-arrays,and the verification and analysis of related methods for suppressing the main and side lobes based on the measured data are given.