The Doppler current meter is a fishery instrument that measures the direction and the speed of tidal current in each depth, and displays it on the graphics screen by the vector and the numerical value, and the key role is borne in deciding the position and timing that the round haul netter throws the fishing net. It is necessary to expand the fishing net at the depth of the aim to raise the haul. Therefore, before throwing the fishing net, it becomes important to grasp the tidal current from the vicinity of sea surface to the aim depth that the fishing net arrives at. Recently, needs of the tidal current measurement of large depth had risen in the trawler and the gill netter, etc. besides the round haul netter.
Our company devised the improvement of the receiving signal processing and the display method, and have developed Doppler current meter JLN-650 that was able to confirm the tidal current from the vicinity of the sea surface to large depth almost continuously, and introduce it as follows.