基于高斯短时分数阶Fourier变换 的海面微动目标检测方法

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.

Gaussian Short-Time Fractional Fourier Transform Based Detection Algorithm of Target with Micro-Motion at Sea

The attitude of target at sea may vary with the fluctuation of sea surface,which induces the effect of power modulation 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 translation 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 obtained 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.