Characterization of the Accmf-system for a Simultaneous Calibration Technique

The Microflown Ultimate Sound Probe (USP) is an acoustic vector sensor capable of measuring the acoustic intensity in 3D and consists of a pressure microphone and a 3D particle velocity sensor. In order to perform a calibration of all three orthogonally positioned components of the particle velocity sensor simultaneously, we calibrate the USP by means of a reference velocity field above a vibrating piston in an ordinary room without anechoic conditions. During measurements and in this simultaneous calibration procedure it is a matter of importance to know the orientation of the USP. Therefore, a 3D-acceleration sensor and the USP are combined to the ACCeleration MicroFlown (ACCMF)-System. In this paper we present a characterization of the ACCMF, where the 3D-acceleration sensor and the USP are analysed concerning the orientation of the axes and the sensitivity of each component of the sensors. Furthermore, we compare our calibration results with the manufacturer’s. Microflown performs the calibration of the USP with the Piston On a Sphere (POS) calibrator and is not able to calibrate the whole frequency range of interest at once and all three components simultaneously. This POS calibration procedure only provides nine calibration parameters, which were obtained from a least square fit of a sensitivity model. For a proper comparison of our obtained calibration results to the POS calibration data, the post processing of the POS calibration procedure is performed by an own implementation of the evaluation process. ACCMF aided calibration results are compared to the results of the POS calibration technique and deviations of the two different calibration procedures are discussed.