SONAR SYSTEM FOR CURRENT METERS AND DOPPLER LOGS

摘要

The invention relates to the emission antennasof Doppler logs and current meters.It consists in distributing the transducers(701) of such an antenna over a circular plane base.The polarities, phases and sequence of feeding thesetransducers with two distinct frequencies F1 and F2make it possible to obtain four emission lobes inclinedby 30° foreward, aftward, to port and to starboard.Appropriate summation of the reception signals makes itpossible to define two fore/aft and port/starboardreception lobes in which the echoes are distinguishedthrough the frequency.It makes it possible to determine the speed ofthe carrier boat independently of the speed ofpropagation of sound in the water. Moreover, the emission baseis plane is substantially smaller than an ordinary basecomprising four groups of inclined transducers.