| 摘要 |
PURPOSE:To enable immediate determination of a net towing course or the like after a finding while facilitating the operation of a ship by jointly indicating depth difference between the sea bottom and school of fish as distance from a wake of the ship. CONSTITUTION:A fish detection circuit [II] stores a reflection information signal based on the depth difference within a specified range including the sea bottom according to a control pulse P1 from a control signal generation circuit [ I ] into a memory 6. A control circuit 9 reads out the contents of the memory 6 in the order of a rising signal of the sea bottom B and reflected signals of fish F2 and F1. A track recorder [III] memorizes a new positional coordinate of a ship, the sea bottom and a fish signal with a memory of an arithmetic unit 14 based on a signal proportional to the azimuth thereof from a gyrocompass 11 and an output proportional to a running distance from a speedometer 12. A display circuit [V]indicates the position of own ship and the position of fish related thereto on a CRT18. |
