Research On Multipath Echo Tracking For Skywave Radar With Array Mutual Coupling And Interferences

Skywave over-the-horizon radar can detect long-distance targets of 1000 to 4000 kilometers by using ionospheric reflection,and has great application value in military and defense fields.However,in practical applications,the sky-wave over-the-horizon radar detection process is affected by ionospheric pollution,multipath effects and strong sea clutter,making the target detection and tracking face a harsh application environment of weak targets,multiple targets,low signal-to-noise ratio,and strong pollution.In this context,the multi-path echo tracking method for sky-wave radar with mutual coupling and interferences is studied to improve the tracking accuracy of sky-wave radar.Firstly,the sky-wave radar signal model and measurement model are established,and the sky-wave radar coordinate registration method is derived.At the same time,the multiple signal classification(MUSIC)for direction-of-arrival(DOA)and the standard Capon beamforming algorithm for interference suppression are introduced.Secondly,the array mutual coupling correction method before target tracking is studied.The forward and backward smoothing MUSIC algorithm with array mutual coupling is introduced.Based on an array mutual coupling coefficient matrix reconstruction method,a mutual coefficient matrix reconstruction method based on importance resampling is proposed.This method can improve the DOA estimation accuracy of the MUSIC algorithm.Then,the interference suppression method before target tracking is studied.Aiming at the problem that the standard Capon beamforming algorithm affects the expected signal when suppressing the interference,a method of reconstructing the interference plus noise covariance matrix based on maximum likelihood resampling is proposed.The key of this method is to evaluate the reconstructed interference plus noise covariance matrix using maximum likelihood estimation.The interference can be more effectively suppressed by using the reconstructed interference plus noise covariance matrix.Finally,the multi-path target tracking method of sky-wave radar is studied,and redundant multi-path interference is removed based on coordinate registration.The target track is formed by particle filtering and volume Kalman filtering.And the application of target tracking method in distributed sky-wave radar is showed.