海上目标随海面颠簸导致姿态变化，引起回波功率调制效应，导致回波多普勒体现时变和非平稳特性。为此，本文将微多普勒理论应用于海杂波中弱目标检测，提出一种基于高斯短时分数阶Fourier变换（GSTFRFT ）的海面微动目标检测方法。首先，建立海面目标的平动和三维转动回波模型；然后，基于海尖峰判别方法对回波信号进行数据筛选，改善信杂比，并采用GSTFRFT对微动信号进行增强处理，利用海面目标与海杂波的微动特征差异设计恒虚警检测方法；最后，通过GSTFRFT域滤波，提取信号的微动特征并得到瞬时频率。实测雷达数据仿真结果验证了算法的有效性，具有在强海杂波中检测微弱目标的能力。%The attitude of target at sea may vary with the fluctuation of sea surface ,which induces the effect of power modu-lation of radar echo ,and also the Doppler reflects time-varying and nonstationary properties .In this paper ,micro-Doppler theory is applied to weak target detection within sea clutter ,and an algorithm of detecting micro-motion target at sea is proposed via Gaussian short-time fractional Fourier transform (GSTFRFT ) .Firstly ,signal model of target on the sea surface is established including transla-tion and 3-D rotation movements .Then ,radar returns are selected based on sea spikes identification for better signal-to-clutter ratio . Moreover ,micro-motion signal is enhanced via GSTFRFT ,and signature differences between target and sea clutter are utilized for designing constant false alarm ratio detector .Finally ,micro-motion signature and instantaneous frequency can be extracted and ob-tained by filtering in GSTFRFT domain .Simulation results with real datasets validate the effectiveness of the algorithm ,which is qualified for detecting weak target in strong sea clutter environment .
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