Horizontal ADCP, new instrument for measuring current speed in a horizontal plane

The purpose of the development is to observe strong currents in narrow channels where many vessels pass through. The instrument is designed to be placed on a vertical wall beneath the sea surface. The instrument utilizes the Doppler shift principal for its measurement. Very narrow acoustic beams are transmitted horizontally to the center of the channel from the transducer and the backscatter signals are analyzed to find current speed and direction. The authors have carried out the field tests at the Kanmon Strait, which is the important sailing route connecting the Sea of Japan and the Seto Inland Sea. the tests confirmed that current speed and direction within 500 m far from the transducer can be measured by the new instruments.