| 摘要 |
Involves at least two different types of detectors (1,2,3) which are set out in the area to be monitored. When an object is detected, they transmit a signal to at least one signal processor (4) which produces a signal showing that a foreign object is present in the area and where it is located. The processor can also calculate the foreign object direction of movement and its speed. - The detector used is a sonar (3) with a registering range of 360 degrees horizontally. and at least 45 degrees downwards, with the signal processor (4) calculating the approx. depth of the foreign object. |
