水下线性调频信号分段循环自相关被动检测法

摘要

Linear frequency modulation(LFM)pulse is one of the most common underwater sound pulse sig-nals.Under low signal-to-noise ratio(SNR),the performance of energy detection、auto-dechirp or phase lock loop method is weak.This paper proposeed a new sectional detection method based on cyclic autocorrelation function envelope to capture and detect LFM signal of underwater white Gaussian noise environment.The pulse width of receive signal was divided into many equal segments,then make cyclic autocorrelation operation respec-tively.At last,put the envelope of cyclic autocorrelation function as test statistic to detect LFM signal.Numeri-cal simulation results demonstrated the superiority of the proposed method to energy detection method under low SNR.%线性调频(LFM)脉冲是最常见的水下声信号波形之一，由于传统上采用的能量检测、自解线频调及锁相环技术在低信噪比条件下检测性能较差，针对水下高斯白噪声背景中的 LFM信号被动检测问题，提出一种基于分段循环自相关函数包络的检测方法，将接收信号脉宽分为等间隔的段，在每段进行循环自相关运算，将循环自相关函数包络作为线性调频信号的检验统计量进行判决，从而有效地实现低信噪比下LFM信号的检测。数值仿真结果表明，在低信噪比条件下该方法的检测性能优于能量检测方法。