Abstract: The paper presents the experimental research associated with hydroacoustic multi-sensor array which is used for positioning object in water environment. Moreover, the paper presents the methodology of determination of target localization from bearing angles, and its accuracy. The construction of multi-sensor array consist of four hydrophones and it has a shape of a tetrahedron. This three-dimensional array is well known as a good solution of passive sonar and it is made of four elements assumed to have identical features and lying on a plane. The position of each hydrophones in a tri dimensional coordinate system correspond to the direction of the arriving acoustic plane wave. These features cause that the tetrahedral antenna has significant civil and military applications.