JPS641995A - Active sonar apparatus - Google Patents

Abstract

PURPOSE: To know the position of a target exactly in three dimensions, by providing means to detect the depth of the target in addition to the bearing and range thereof.

CONSTITUTION: A target detection unit 6 calculates an apparent range Rf along a sound ray 22 to a target 20, from a difference between the time of emission of a sound wave and the time of reception of a reflected wave, and supplies same to a sound ray calculator 1. A horizontal bearing detection unit 7 supplies the angle of access of a reflected sound in the horizontal direction, i.e. a horizontal direction angle ψ, to a target position calculator 2. A vertical bearing detection unit 8 detects an apparent angle θ of access in the vertical direction of the target 20 from the angle of access of the reflected sound, likewise, and supplies same to the calculator 1. The calculator 1 calculates the curve of the sound ray at the pertinent depth by using the correlation data on the depth of water and the velocity of sound stored beforehand, as well as the depth of a sonar transducer and the angle θ of access in the vertical direction, and supplies same to the calculator 2. A display unit 3 displays one point in a three- dimensional space in the sea on the basis of a range Rf and a direction angle ϕfrom the calculator and the direction angle ϕ from the detection unit 7.

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