Research Of Target Angle Estimation On Distributed Multi-Shipborne HFSWR

Distributed Multi-Shipborne High Frequency Surface Wave Radar(DMSHFSWR)is a radar system with larger array aperture that can be processed by the radar equipment on different ships,so it has stronger angle-measuring ability and detection ability.And thanks to the flexibility of the ship’s platform,the system can work better in the changing ocean environment.Therefore,the target azimuth estimation method of DMS-HFSWR has important research significance.Firstly,the signal model of DMS-HFSWR is analyzed.Based on the model,three DOA estimation methods of DMS-HFSWR are studied and their performances are analyzed.The influence of factors such as signal-to-noise ratio,number of virtual array elements and array spacing on the MUSIC algorithm based on Virtual Interpolation Array transformation(VIA-MUSIC)and Dual-Resolution ESPRIT(DR-ESPRIT)algorithm is analyzed by simulation.The simulation results show that the estimation performance of the DR-ESPRIT algorithm is better.According to the motion characteristics of the shipborne radar system,the basic principle of the Synthetic Aperture(SA)algorithm is studied,and the comparison with the conventional MUSIC algorithm shows the advantages of the method.Then,in view of the limitation that the DR-ESPRIT algorithm is only suitable for satisfying the dual-resolution translation invariance array,combined with the virtual interpolation transformation method,this paper proposes a DR-ESPRIT algorithm based on virtual interpolation transformation(VIA-DR-ESPRIT),which can be applied to DMS-HFSWR which has the complex and changeable array distribution.In view of the situation that the DMS-HFSWR system is in a relatively static state,this paper analyzes the different array distribution situations and different array element distribution situations of the radar system,and discusses 11 possible distribution situations in radar systems.The performance of different DOA estimation algorithms in these 11 situations is studied by simulation.The simulation results show that the VIA-DR-ESPRIT algorithm has better DOA estimation performance when applied to the DMS-HFSWR.Finally,the DOA estimation method under the relative motion state of DMSHFSWR is studied.Aiming at the problem that the performance of DOA estimation is degraded due to the difference of the array structure before and after virtual interpolation transformation,this thesis studies a Synthetic Aperture algorithm based on virtual interpolation transformation(VIA-SA).At the same time,in view of the time-dependent data received by the time-varying array,the virtual interpolation transform is used for time-invariant processing.The midpoint method and the segment method are studied in this paper.The DOA estimation method based on these two methods is studied and compared with the VIA-SA.The simulation results show that the segment method has more advantages than the midpoint method.At the same time,the VIA-DR-ESPRIT algorithm has the advantages of better goniometric performance.Finally,various array distribution situations in motion state are discussed,and simulation experiments and performance analysis of different DOA estimation algorithms are carried out.