To sufficiently ensure safety of a diver even without using a complicated and expensive communication apparatus.
In a method for performing underwater communication between one master unit 1M and a plurality of slave units (1Sa-1Sc) by using ultrasonic waves, the master unit and slave units are communication apparatuses each having an ultrasonic oscillator 40 and communication sections (41, 42) for performing communication by using ultrasonic signals. The master unit stores identifiers of the respective slave units, and each of the slave units individually stores the identifier. The master unit transmits a signal for distance measurement toward each slave unit (s43), and the slave unit returns, to the master unit, a reception signal including the identifier when the signal for distance measurement is received (s52a-s52c). The master unit acquires relationships of distances to the respective slave units specified based on the time required for communication related to the transmission of the signal for distance measurement and the return of the reception signal from the slave unit, determines priorities of the respective slave units in order from longer distance (s46), and performs communication in order from the slave unit of higher priority (s47a-s47c, s54a-s54c).
JP2008265527A | 2008-11-06 | |||
JP2008531984A | 2008-08-14 | |||
JP2008265527A | 2008-11-06 | |||
JP2008531984A | 2008-08-14 |
Osamu Suzawa
Kazuhiko Miyasaka