Research Of Targets Super-resolution Direction Finding And Rectification Method For HFSWR

High frequency ground wave radar has the ability of over-the-horizon detection,because of large observation range and all-weather work,etc,it is becoming more and more popular.Because array aperture of the radar system is small,it is not sensitive to the bearing of the target,and this leads to the low accuracy of the target direction finding.Because of super-resolution method's higher resolution is widely used,without increasing array aperture radar.Currently super-resolution method is mainly include classical MUSIC algorithm and improved MUISC,This paper aims at the practical application of radar,super-resolution measurement and correction method are studied to improve the accuracy of radar direction finding.Main work of this paper is as follows:(1)The comparison of typical super-resolution direction finding method is proposed to be analyzed.It introduces the principle of classical MUSIC algorithm,and the simulation analyze the factors that affect the performance of direction finding algorithm.For different factors,the improved MUSIC algorithms are analyzed with the simulation.Using the measured radar data,MUSIC algorithm and improved algorithm are compared to verify.In practice,it provides the reference basis to select the appropriate algorithm.(2)The improved MUSIC algorithm has the problem that can't direction finding for the fast time-varying signal,single snapshot MUSIC algorithm is studied.The single snapshot dimensionality reduction MUSIC algorithm estimates the covariance matrix of dimension reduction algorithm,which reduces the performance of DOA estimation problem.We put forward the array-based data rearrangement single snapshot MUSIC direction finding method for HFSWR.The array receive a snapshot of data arranged in a Toeplitz matrix,and then estimate the covariance matrix to solve the array aperture losses.Simulation and experimental validation data analysis showed that the array-based data rearrangement single snapshot MUSIC direction finding method for HFSWR.Compared with dimensionality reduction algorithm,it not only improves the position estimation accuracy and has higher resolution.(3)Because of the super resolution method in direction finding has errors in practical application.Based on the AIS data,the rectification method of super-resolution direction-finding HFSWR is studied.Because of the performance of subspace rectification method has edgradation problems in the case of low SNR,an improved subspace rectification method is equivalent.We introduce the principles and processing of the method and compared by simulation analysis to verify the improved method has higher azimuth rectification performance at low SNR.Finally,Combined AIS and HFSWR measured data,The performance of the subspace rectification method and improved subspace rectification method is evaluated and analyzed.