SONAR METHOD FOR DETECTION OF UNDERWATER OBJECTS MOVING AT LOW RADIAL VELOCITY IN CONTROLLED WATER AREA AND SONAR CIRCULAR SCANNING STATION REALIZING THIS METHOD

摘要

FIELD: hydroacoustics, applicable for detection of underwater objects moving at a low radial velocity in the controlled water area.;SUBSTANCE: the method is based on successive irradiation of water space by hydroacoustic signals in different directions, reception of echo signals from fixed objects and objects moving at a low radial velocity, demodulation, filtering and display of the received echo signals on the screen of the two-coordinate indicator. At the same time K "radiation-reception" cycles are accomplished in m directions, all the received echo signals discredited in l elements of the distance are memorized, displayed on the screen of the two-coordinate indicator in the form of luminous marks so that in each of m directions successively K times l elements of the distance are displayed. The decision of detection of the object by the m-th direction is taken by appearance on the respective section of the indicator screen of a path formed by the luminous marks of the echo signal, obtained in K "radiation-reception" cycles. The detected objects moving at a low radial velocity and the fixed objects are classified by the presence of inclination of the luminous marks of the echo signals from the moving objects determined by variation of the distance to them and absence of inclination of the luminous marks of the echo signals from the fixed objects. The sonar station has a hydroacoustic cylindrical antenna of piezoelectric transducers combined in n identical bands, "radiation-reception" selector switch, generating device, reception channel. Each band is turned about its axis relative to the adjacent band so that the acoustic axis of the directional pattern of each i-th transducer of one band is shifted relative to the acoustic axis of the directional pattern of the i-th transducer of the adjacent band through angle ϕ=2&Pgr;/mn.;EFFECT: provided detection and classification of underwater objects moving at a low radial velocity, as well as reduced loss of power at radiation of hydroacoustic signals and enhanced signal-to-noise ratio at reception of reflected signals in a circular scanning sonar.;3 cl, 2 dwg