METHOD FOR DETERMINING COORDINATES OF UNDERWATER OBJECT IN SHELF-DEEP SEA TRANSITION ZONE Russian patent published in 2021 - IPC G01S15/08 

FIELD: hydroacoustics.

SUBSTANCE: invention relates to applied hydroacoustics and can be used in the development of rangefinder type hydroacoustic navigation systems that determine the coordinates of underwater objects (UO) in the shelf-deep sea transition zone. The method includes the installation in the marine environment outside the surf zone of at least two stationary hydroacoustic beacons (HB), synchronized by a system of uniform time with each other and with the UO, the introduction of the coordinates of each HB into the on-board device for calculating the coordinates of the UO, the emission of complex acoustic signals by the HB at a frequency below 10 kHz with embedded in them by coding the conventional HB number and radiation time, reception of acoustic signals by a combined receiver UO with fixation of the reception time, extraction by decoding from the received acoustic signals of the HB number and the time of emission of the acoustic signal, determination of the group delay time of the acoustic signal along the HB-UO route. The distances between the HB and the UO are determined using a predetermined profile of the vertical distribution of the speed of sound in the marine environment, the slip angle at the location of the UO and the phase velocity, a predetermined invariant and the invariant velocity as the velocity of an inhomogeneous wave corresponding to zero reflection coefficient of the water-sea bottom. The positioning horizon of the UO during the determination of the distance is set as close as possible to the seabed in case of movement in a shallow sea or as close as possible to a predetermined axis of the underwater sound channel when moving in deep sea. After determining all the required parameters, the desired distances between the HB and the UO are entered into the on-board device for determining the coordinates of the UO and the coordinates of the UO are determined in the local coordinate system associated with the HB, or in the geographic coordinate system.

EFFECT: invention reduces the error in determining the coordinates of the UO in the absence of access to satellite navigation systems, increases the accuracy of determining the coordinates of the UO.

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