基于小波变换的舰船辐射噪声检测

On Detecting Ship Noise with a New Method Based on Wavelet Transform

分析了舰船辐射噪声 (简称舰船噪声 )与 1 /f信号的关系 ,提出了一种基于小波变换的信号检测方法 ,对白噪声背景下的舰船辐射噪声进行了检测 ;推导了相应的检测统计量及其统计分布特性 ,并与传统的匹配滤波器、能量检测器进行了比较 ,计算机仿真结果证明了本方法是有效的 。

When SNR (signal to noise ratio) is low, detecting ship noise with traditional methods such as energy detector and matched filter is not quite effective. We now propose a new method based on coefficients of wavelet transform. Our method is based on the fact that, although ship noise appears to be very disorderly as shown in Fig. 1, its power spectrum attenuation has the same characteristic as 1/f signal shown in Fig. 2. Subsection 2.2 points out that 1/f signal can be mathematically treated with wavelet transform. Subsection 3.1 derives Eq.(9), which involves coefficients of wavelet transform, as the important criterion needed for computer detection of ship noise. Subsection 3.2 gives computer simulation results. Fig. 3 compares our wavelet transform method (curve marked WT) with energy detector method (curve marked ED) and matched filter method (curve marked MF). These results show preliminarily that our new method is indeed effective