acoustic doppler current profiler acoustic seabed classification acoustic location acoustic mine albert beaumont wood alexander behm alternating current analog signal animal echolocation array gain band-pass filter bat beached whale beamforming bioacoustics british h class submarine bulk modulus captor mine canary islands cavitation chirp clearance diver convection decompression sickness deep sea density depth charge digital object identifier dolphin doppler echo sounding electrical generator electrostatics empirical endangered species act figure of merit fish finder fishfinder fishing flotilla fourier transform frequency fuel cell hertz hydroacoustics hydrophone hydropower inverse-square law isle of portland lbl long-term mine reconnaissance system moss marine mammal protection act mass montreal morgan electro ceramics multibeam echosounder nato national environmental policy act natural resources defense council nautical mile naval mine naval warfare navigation nixie noise dosimeter noise level nuclear submarine ocean acoustic tomography oxford english dictionary oyashio class submarine parametric array passive acoustics passive radar patent paul langevin piezoelectricity pillenwerfer plan position indicator pressure propeller pulse pulse compression radar refraction reginald fessenden robert william boyle royal navy sodar sofar channel spie salinity shipping shoal side-scan sonar signal-to-noise ratio signal processing sonobuoy sound space shuttle columbia spectrogram speed of sound sphere submarine sustainability synthetic aperture sonar target strength terfenol-d thales underwater systems thermocline towed array sonar trajectory transducer transformer uk intellectual property office underwater port security system underwater acoustics united kingdom of great britain and ireland united states united states navy upward looking sonar vanguard class submarine vibration visibility whale world war i world war ii wrench