Calibration of Standard Hydrophones in the Frequency Range of 20 Hz to 200 kHz at 10 MPa Hydrostatic Pressure

This paper describes the coupler reciprocity method and free-field reciprocity method used for standard hydrophones calibration in the frequency range of 20 Hz to 200 kHz at 10 MPa hydrostatic pressure, and the coupler reciprocity calibration facility working in the frequency from 20 Hz to 3.15 kHz and free-field reciprocity calibration facility working in the frequency from 3.15 kHz to 200 kHz was established on these methods. Standard hydrophones RHC14 and RHS30 were calibrated separately using these facilities, and their sensitivities at 10 MPa hydrostatic pressure was presented. Analyze of measurement uncertainties proved that the expand uncertainty (at k=2) of coupler reciprocity calibration facility was 0.5 dB, and free-field reciprocity calibration facility was 0.7 dB (below 100 kHz) or 0.9 dB (100 kHz to 200 kHz).The construction of these facilities and capabilities sets the test foundation for deep-diving underwater sound devices.