| 摘要 |
PURPOSE:To elevate the accuracy with an object measurement by measuring the direction of receiving an ultrasonic signal emitted of a depth detector accurately with a measuring device on the bottom of a ship to detect the net position based on the direction and depth information. CONSTITUTION:A depth detector 2 fixed on a net cast detects a water pressure and outputs depth information as ultrasonic signal. On the other hand, this apparatus is provided with an ultrasonic wave measuring device comprising ultrasonic vibrators Z(O)-Z(K-1) mounted on the bottom of a ship with the finding range set over the entire perimeter below the bottom of the ship, a vibrator scanning means 30 for scanning the ultrasonic vibrators in the vertical and horizontal ways, a max. reception level detection circuit 5 for detecting the maximum of the ultrasonic signal level from the detector 2 at the scanning position of the respective vibrators scanned by the means 30 and latch circuits 40-45 for latching the vibrator scanning position of the means 30 at the timing detecting the max. reception level of the circuit 5. Then, the net position is detected from the vibrator scanning position latched with the reference line and the depth information of the detector 2. |
