Expanded Target DOA Estimation for Shipborne HFSWR Based on Toeplitz Covariance Reconstruction With Time-Trequency Information

The manoeuvring motion of shipborne High Frequency Surface Wave Radar (HFSWR) platform can cause the target echo signal to expand, leading to a reduction in the target echo amplitude and signal-to-noise ratio (SNR), which adversely affects the Direction of Arrival (DOA) estimation of the target. To solve this problem, this paper proposes an extended target DOA estimation method based on Toeplitz covariance reconstruction with time-frequency information. Firstly, the method adopts a time-frequency analysis process combined with heading compensation to extract the ridges of the extended target signals, which lays the foundation for making full use of the time-frequency information of the extended target to construct the covariance matrix. Then, the constructed covariance matrix undergoes Toeplitzification, which suppresses the non-stationary noise, improves the target SNR, and solves the problem of the degradation of the extended target’s SNR, thus realizing accurate DOA estimation. Finally, the proposed method is validated by simulation and measured data, and the results show that the root mean square error of the proposed method is reduced by 1.2° compared to the single-peak MUSIC and DBF methods under the same SNR and target expansion, thereby proving the effectiveness of the proposed method.