一种水声瞬态信号的下降沿检测方法

A Falling Edge Detection Method of Underwater Transient Signals

基于最大似然比准则,在高斯分布方差变化的假设下推导了水声瞬态信号累积和下降沿检测的检验统计量和非线性量的概率密度函数表达,重新利用FFT(Fast Fourier Transform)法分析了累积和性能模型,基于纽曼皮尔逊准则计算了在一定检测概率和虚警概率假设下方差和检测门限,并利用舰船转舵仿真信号、鱼雷出管仿真信号和水池重物落水实测脉动信号进行了检验.验证结果表明,相比常规方法,低信噪比下该方法对水声瞬态信号下降沿的判断精确度更高,稳健性更好.

In this paper,based on the maximum likelihood ratio(MLR)criterion,the test statistics and the probability density function of non-linearity of the Page test are derived to detect the falling edge of underwater transient signals under the assumption of variance change of Gaussian distribution.The performance of the Page test is analyzed by FFT(Fast Fou⁃rier Transform)method again.The variance and detection threshold under certain detection probability and false alarm prob⁃ability are calculated based on Newman Pearson criterion.The simulation signals of ship steering,torpedo ejecting and the measured signal of heavy falling obtained in the anechoic tank are exploited to verify the algorithm.The results show that,compared with the conventional method,this method has higher accuracy and better robustness in judging the falling edge of underwater transient signal at low SNR.