| 摘要 |
PURPOSE: To provide a system for giving prior warning of a navigation a dangerous matter at the sea bottom which jeopardizes safe navigation of a ship. CONSTITUTION: A sonar system includes a sonar transmitter/receiver 16 equipped with a ship in the forward monitoring direction. A processor 42 produces a declivity contour generated by a sonar of the sea bottom area in front of a route of a ship 10. A memory 40 stores the declivity contour of the sea bottom area in front of the ship, and the contour is generated from the chart depth data. The declivity contour generated by the stored chart depth data is compared with the declivity contour generated by a sonar reflected wave to determine whether the declivity contour generated by a sonar and the declivity contour of the depth data shown in a chart agree with each other or not. If the declivity contour generated by a sonar reflected wave in the sea bottom area is larger than a predetermined threshold level (selected to identify possible front dangerous matter in the sea bottom) and the contour generated by the chart depth data on such area does not display this possible dangerous matter, the abnormality is identified and a signal showing such abnormality is generated. |
