Particle velocity estimation based on a two-microphone array and Kalman filter

Abstract

A traditional method to measure particle velocity is based on the finite difference (FD) approximation of pressure gradient by using a pair of well matched pressure microphones. This approach is known to be sensitive to sensor noise and mismatch. Recently, a double hot-wire sensor termed Microflown became available in light of micro-electro-mechanical system technology. This sensor eliminates the robustness issue of the conventional FD-based methods. In this paper, an alternative two-microphone approach termed the u-sensor is developed from the perspective of robust adaptive filtering. With two ordinary microphones, the proposed u-sensor does not require novel fabrication technology. In the method, plane wave and spherical wave models are employed in the formulation of a Kalman filter with process and measurement noise taken into account. Both numerical and experimental investigations were undertaken to validate the proposed u-sensor technique. The results have shown that the proposed approach attained better performance than the FD method, and comparable performance to a Microflown sensor.

Reproduction of the vibroacoustic response of panels under stochastic excitations using the source scanning technique

“…Thus, the particle velocity can be obtained by evaluating the pressure gradient ∂p/ ∂x3 [29,30] by using the two point nite dierence method…”

Research on the Detection Technology of Audible Noise Sources of UHVDC Transmission Lines

“…There are two methods to measure sound intensity: (1) The method, a combination of a pressure microphone with a particle velocity transducer, is limited for measuring the sound intensity in near fields, resistant fields and unsteady fields [15]. (2) The method, making use of two closely spaced pressure microphones to obtain the particle vibration velocity, has been widely employed in engineering surveys [16][17].…”

Archives of Acoustics

“…Inaccuracies in the estimated pressure gradient in the P-P method increase as the wavelength approaches the Nyquist limit in spatial frequency. Also at larger wavelengths, the pressure difference between the microphone's measurements will be smaller, which can be easily corrupted by the noise and cause an error in the pressure gradient approximation, and thereby, the acoustic intensity (Bai et al, 2013;Miah, Hixon, 2010). In addition to the P-P and P-U based vector sensor, there are other direction sensors known as ambisonic microphones (also called SoundField microphone) which can capture sound fields from 360 ○ space (in addition to the horizontal plane, it captures sound fields from above and below the listener plane).…”