Preface of MBES(MultiBeam Echo Sounder) system

 The system transmits the shape echo sounder beam from the transmitter and receives the beam reflected from the seabed using the hydrophone.
 The water depth is calculated from the travel time of the beam between the transmitter and the receiver.
 Having many transmitters make fan beams across the keel, this system can obtain a lot of bathymetric data on a wide angle at once.
 The travel time of the beam (from the transmitter to the seabed and from the seabed to the receiver) is corrected using the vertical profile of the sound velocity obtained from the in situ observations.