| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a collecting undersea sensor system that detects existence of a fish shoal and can acquire information about a present position of the fish shoal, a base station for acquiring information about the fish shoal from the collecting undersea sensor system, and an optimal navigation device for guiding a fishing boat based on the information about the fish shoal acquired from the base station. <P>SOLUTION: Undersea sensor devices 3 have an ultrasonic radar, and operate in one of a first operation state of transmitting ultrasonic pulses with a certain frequency and a second operation state of transmitting the ultrasonic pulses with a frequency higher than the former frequency. The undersea sensor devices 3 detect a fish shoal in the first operation state, and transmit an informative signal to the base station 4. The base station 4 specifies an undersea sensor device 3 to be put into the second operation state based on the informative signal, and transmits an operation command signal to the collecting undersea sensor system 2. The undersea sensor device 3, on receiving the operation command signal and recognizing that itself is specified, starts the operation in the second operation state. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
