The Research Of Calibration Method For Plural Hydrophone Sensitivity Using Laser Doppler Technique

With the development of the technique of modern underwater acoustics and the improvement of sonar equipment, the requirement for performance of sonar elements is increasing. In modern digital sonar equipment, hydrophones are mainly applied to collect signal waveforms. To achieve this target signals reversion, we should know the plural sensitivity of hydrophone elements — the phase sensitivity and amplitude sensitivity. Although the improved normal three transducers reciprocal method can obtain plural sensitivity, when the calibration frequency comes up to a thousand hertz, it's impossible to eliminate the influence of distance factor completely, and make the uncertainty of phase calibration increase linearity with frequency. This paper is to study the calibration of the plural sensitivity of hydrophone using laser Doppler vibrometer technology in the frequency range form ten kilohertz to hundred kilohertz, and take steps to make the uncertainty of calibration in the stipulation scope.Firstly, the paper introduces the basic knowledge of laser Doppler measure. It consist of the principle and construct of Doppler vibrometer, the application of Laser Doppler vibrometry technology in the acoustical measurement, and three types laser measurement method commonly used in underwater acoustic.Secondly, it will deduce calibration formula for hydrophone plural sensitivity of three transducers reciprocals method and laser method in detail. And we not only take the relations between vibration velocity measured by laser interferometer and surface velocity of membrane under the acousto-optic function into account, but also offer the phase response and amplitude response curves of equivalent refraction coefficient, now it afford the theory basis for the calibration data revision. Finally, according to the calibration principle, we constructed the experimental system, and analyzed the whole measurement system's uncertainties.