JPS55152484A - Oblique sweeping acoustic searching system - Google Patents

Abstract

PURPOSE:To enable accurate depth measurement or the like in oblique sweeping, by using prescribed clock pulses corresponding to the inclination angle of a swingable transmitter-receiver to control a memory circuit into which a reflection signal is stored. CONSTITUTION:When a transmitter-receiver is inclined at an angle of theta to the horizontal plane by a swing mechanism 6 and a point P on an oblique underwater ground 2 or the like is acoustically searched, a reflected wave signal from a reception amplifier 7 is stored into a memory circuit 10 at prescribed clock frequency F. The clock frequency F is changed into outputs F/sintheta, f/costheta by a converter 9 which is regulated by a controller 8 in proportional to the inclination angle of the swung transmitter-receiver 3. The outputs are used as clock pulses to read recorded signals from the memory circuit 10 to determine the distance B between a measuring point S and another point S' just above the under-water point P and the depth C thereto. Outputs representing the distance and the depth are shaped and entered into a recorder 4 so that the shaped outputs are recorded. Accurate depth measurement can thus be effected even for the underwater ground of unknown gradient.