A PassiveSonar SystemforSearching Acoustic Beacons inDeep Sea

Authorsdeveloped a passive sonarsystemfor searching rocket boosters withacoustic beacons, whichwillbe launched byJAXAwithH2A rocket, detached fromtherocket, andsinkunderdeepsea.Thesystem consists ofanunderwater unitthatcanbeoperated at6500mdeepandanonboardunit withsignal processing anddisplay functions. Theunderwater unitismountedonROV whichistowedbyamothershipat 5001000mabovethebottom. Thesystem provides detection and alocalization functions. Thedetection isrealized byusing two linear, multi-element, hydrophone arraysreceiving acoustic pulses radiated fromacoustic beacons frombothsides, multi- beamformers, andwaterfall displays. Thelocalization isrealized byusing a 4-element planar hydrophone arrayandanSSBL acoustic positioning signal processing. The acoustic signals received bythehydrophone arrays aredigitized andtransmitted totheonboard unitviaanoptical fiber cable. Theonboard unit consists oftwoPC's, whichexecute signal processing anddisplay functions.