Patent ID: 8059485

Claim:
A communication system for obtaining predetermined information from an underwater terminal via a sonobuoy, comprising: an underwater terminal for transmitting and receiving sound wave signals; a base station apparatus for transmitting and receiving radio wave signals; and a plurality of sonobuoys for transmitting and receiving said sound wave signals to and from said underwater terminal, and for transmitting and receiving said radio wave signals to and from said base station apparatus, wherein said base station apparatus selects one of the sonobuoys having a highest communication quality of based on both communication quality said sound wave signals and communication quality of said radio wave signals, and obtains prescribed information from said underwater terminal via the one of the sonobuoys selected, wherein said one of the sonobuoys capable of detecting said sound wave signal from said underwater terminal calculates a communication quality of said detected sound wave signal and transmits information on said communication quality of said detected sound wave signal to said base station apparatus using said radio wave signals, wherein said base station apparatus calculates said communication quality of said radio wave signal and selects said one of the sonobuoys as having the highest communication quality based on said communication quality of said sound wave signal and said calculated communication quality of said radio wave signal, and wherein said base station apparatus selects said one of the sonobuoys having said highest communication quality at least by: receiving said radio wave signals transmitted from said plurality of sonobuoys; selecting said radio wave signals corresponding to each of said plurality of sonobuoys; calculating each communication quality of said radio wave signals; demodulating said radio wave signals and extracting said each communication quality of said sound wave signals in said demodulated radio wave signals; selecting the sonobuoy having the highest communication quality based on both said each communication quality of said sound wave signals and said each communication quality of said radio wave signals.