The involvement with the CIPM highlights USRD’s presence with an international community emphasizing the promotion of world-wide uniformity in units of measurement and their traceability to the International Systems of Units (SI). CIPM meets in accordance with the BIPM (International Bureau of Weights and Measures). Significant external test events of this nature have involved USRD’s past and continuing participation in the CIPM (International Committee for Weights and Measures) Key Comparison for the Calibration of hydrophones in the frequency range from 1 kHz to 500 kHz. The data gathered from these measurements is used as part of an overall quality assurance process. Gas and bubble production by siphonopheres (Naval Undersea Warfare Center, 1967), by George V Pickwell and Naval Undersea Warfare Center (U.S.) (page images at HathiTrust US access only) An investigation of XBT encoding errors and their effect on sonar range prediction (Naval Oceanographic Office, 1977), by Alvin Fisher, L Riley, and United. The Round Robins allow comparisons of measurements to be made on the same physical unit at multiple test locations. These Round Robin units are comprised of a representative set of hydrophones covering the significant frequency range over which measurements are typically conducted in the underwater acoustics arena. USRD participates in internal and external tests of devices designated as Round Robin units. Staff members who helped achieve the designation include, front row from left, Anthony Paolero, Michael Bergeron and Joseph Sheltry. The reciprocity technique is performed at USRD within acoustical free-field test environments and within small pressure vessels (designated as Reciprocity Couplers) for applicable low frequency measurements. THE NAVAL UNDERSEA Warfare Center Division Newport’s Underwater Sound Reference Division has been named a Designated Institute by the National Institute of Standards and Technology. This technique utilizes the measurement of electronic parameters coupled with an intimate knowledge of the controlled acoustic environment under which the measurements are undertaken. Primary calibrations of acoustic receive sensitivity for underwater hydrophones are accomplished via the use of the reciprocity calibration technique. USRD has had and continues to have key involvement in the content and structure of the ANSI/ASA S1.20 standard. These are, respectively, nationally and internationally recognized standards. Underwater acoustic metrology related activities at the USRD are multi-faceted in the protocols, depth and capabilities related to acoustic reference services.įormalized protocols established in ANSI/ASA S1.20 (Procedures for Calibration of Underwater Electroacoustic Transducers) and, to a degree, those established in IEC 60565 (Underwater acoustics - Hydrophones - Calibration in the frequency range 0,01 Hz to 1 MHz ) form the foundation of the standardized procedures utilized in the underwater acoustic calibration work performed by USRD.
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