The article deals with the detection of hydro acoustic signals in the case of a negative signal-to-noise ratio. The ambiguity of the linear (classical) correlation algorithm is shown when solving the problem of detecting a DSSS signal under real operating conditions in the case of using the criterion of the maximum value of the correlation function on the observed interval. A method is proposed for determining the threshold value for a reliable and accurate detection of a complex phase-manipulated signal using symbolic correlation in information, measuring and control sonar systems. The accuracy of the detection is not worse than the symbol duration. A method is used for DSSS signals modulated by pseudorandom or Gold sequences. The organization the numerical and field experiments are described. The results obtained in the course of the experiments confirm the correctness of the proposed method. Application of the method in digital signal processing units for sonar systems allows the creation of asynchronous navigation, communication and control systems in the implementation of both single cast and multi-cast service in underwater data collection networks, the elements of which can be underwater vehicles and monitoring stations.
