Acoustic intensity sensor using a mems triaxial accelerometer and mems microphones
AssigneeAIVS Inc.
InventorsJames W. Waite, David Raymond Dall'Osto, Peter Hans Dahl
Life of this patent
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Abstract
An airborne acoustic vector sensor for simultaneously measuring triaxial particle acceleration in three dimensions and pressure includes a triaxial MEMS accelerometer sensitive to an Earth gravitational field. The airborne acoustic vector sensor includes one or multiple MEMS microphones sensitive to sound pressure and overlapping the accelerometer in frequency. The airborne acoustic vector sensor includes a solid body having a density approximating a density of air. The accelerometer is mounted in or upon the solid body. The airborne acoustic vector sensor includes a suspension system supporting the accelerometer and solid body within a framework.
Claims20
An airborne acoustic vector sensor for simultaneously measuring triaxial particle acceleration in three dimensions and pressure, comprising:
- a triaxial MEMS accelerometer sensitive to an Earth gravitational field;
- one or multiple MEMS microphones sensitive to sound pressure and overlapping the accelerometer in frequency;
- a solid body having a density approximating a density of air, the accelerometer mounted in or upon the solid body;
- and
- a suspension system supporting the accelerometer and solid body within a framework.
A calibration method for an acoustic vector sensor comprising a MEMS triaxial accelerometer mounted within or upon a solid body and one or multiple MEMS microphones, comprising:
- first calibrating frequency independent scale factors and zero offsets of each of a plurality of axes of the triaxial MEMS accelerometer, independent of any acoustic stimulation and relying just on a constant Earth gravitational field;
- and
- second calibrating amplitude and phase calibration factors for the MEMS microphones in a free-field acoustic environment, in relation to an amplitude and phase reference that is equal to an integrated acceleration of the MEMS accelerometer multiplied by an acoustic impedance of air, and a constant proportional to a ratio of a combined density of the solid body and the MEMS accelerometer to a density of air.
Dependencies are inferred from the claim text.