一种基于广义互相关的水声直扩信号检测方法

直扩信号因其低功率谱密度特性使得检测十分困难,针对传统自相关法在低信噪比条件下检测性能急剧下降的问题,在分析了直扩信号自相关特性的前提下,提出一种基于广义互相关估计的直扩信号检测方法.首先对接收信号分段并对相邻信号段分别进行广义互相关估计,估计结果采用二阶矩非相干积累,提取相关峰获得检测统计量,将检测统计量与门限比较,...

A detection method of underwater acoustic DSSS signal based on generalized cross-correlation

Direct sequence spread spectrum (DSSS) signal is difficult to detect due to its low power spectral density characteristics. Aiming at the problem that the performance of traditional auto-correlation detection method for DSSS signal degrades sharply under the condition of low signal-to-noise ratio (SNR), according to the analysis of autocorrelation characteristics of DSSS signal, a detection method based on generalized cross-correlation (GCC) estimation is proposed. Firstly, the received signal is segmented and the generalized cross-correlation estimation for adjacent segmented signals is performed successively, then the estimated results are processed by non-coherent accumulation of the second-order moment to extract cross-correlation peaks as detection statistics, which are compared with a certain threshold to determine whether a signal exists or not. The comparison between the performances of the improved autocorrelation detection method and the proposed method in this paper is made by computer simulation, and the result shows that the SNR tolerance of the proposed method is reduced by 5 dB compared with the improved auto-correlation method, and the proposed method can detect DSSS signals under low SNR condition. The processing result of pool test data also verifies the practicability of the proposed method.