A DOA Estimation Method of Distributed Multi-shipborne High-frequency Surface Wave Radar under Ship Swing State

Distributed Multi-Shipborne High-Frequency Surface Wave Radar (DMS-HFSWR) system combines the advantages of long-range detection of high-frequency surface wave radar and the maneuverability of traditional single-ship radar. By jointly processing radar data from each ship platform, the radar aperture is increased, thereby enhancing target detection and angle measurement capabilities. Therefore, Direction of Arrival (DOA) estimation of DMS-HFSWR has significant research significance. However, for the DMS-HFSWR system, the motion of the carrier platform can reduce the performance of DOA estimation. To overcome this difficulty, the impact of the forward and six-degree-of-freedom (6-DOF) motion of the platform on the receiving array posture and its array manifold is firstly analyzed. Then, this paper utilizes the derived antenna position coordinate transformation matrix under ship swing conditions to propose a method that corrects the transformation matrix in the virtual interpolation transform with ship swing angle information, thereby improving the accuracy of DOA estimation results. Finally, this paper conducts simulation analysis. A signal model for distributed multi-ship high-frequency surface wave radar is established. Based on this, the MUSIC algorithm based on virtual interpolation array transformation (VIA-MUSIC) and the Dual-Resolution ESPRIT algorithm based on virtual interpolation array transformation (VIA-DR-ESPRIT) are simulated. Time-invariant processing in the virtual interpolation transformation is carried out using segmentation. The simulation verifies the impact of ship swing on the DOA estimation results of the distributed multi-ship array, and comparative analysis demonstrated the effectiveness of the proposed correction method. The experimental results demonstrate that method in this paper can be used in the DOA estimation of DMS-HFSWR to improve the accuracy of the estimation results.