Ship Target Micro-Doppler Feature Extracted by Multi-Synchrosqueezing Transform and Inverse Radon Transform

Ship targets with oceanic waves appear a unique micro-Doppler (m-D) feature, which is important for target identification. In this paper, we propose a method to extract the features of ship target based on Multi-Synchrosqueezing Transform (MSST) and Inverse radon transform (IRT). Firstly, we analyze the complex relative motion between radar and the ship target. After the envelope correction, the echo is a sinusoidal frequency modulation (SFM) signal mixed with a remained time-varying phase. However, it is a challenge to extract the m-D feature directly. Thus, the MSST is used to enhance the TF spectrum concentration, in order to extract the remained phase with m-D characteristics accurately by IRT. The experimental results prove the effectiveness of the proposed method and the accurate estimation of micro motion features.