Title: SEAFAC Acoustic Sensors And Instrumentation
Abstract: Abut# -The success of the submarine noise reduction program has dramatically reduced the radiated noise from U.S. submarines.Lower submarine radiated noise levels coupled with increased Ocean traffic has created a challenging measurement problem.As submarines have gotten quieter the Ocean they operate in has become noisier, thus making it more difficult to measure submarine radiated noise.It is important to make the distinction betwetn a detection system and a measurement system.A detection system can operate a t very low signal to noise ratios and still answer the question is there anything there?A measurement must go beyond detection, but must provide answers to additional questions.What is the absolute sound pressure level?What is the source(s)?The area where the distinction between a detection and measurement system is most noticeable is the type and quality of data.A measurement system provides the engineering data necessary to affect changes in submarine design and/or submarine systems design.The accuracy and repeatability of the measurement is central when considering that data from the measurement will be utilized in deciding whether a multi-million dollar ship alteration or design modification is pursued.Among the most important criteria in the design and implementation of a measurement system for submarine radiated noise are: an understanding of the submarine noise spectra, measurement site environment, acoustic sensor selection and instrumentation.The design of the SEAF'AC measurement system will be viewed as a sequential consideration of these criteria.