Simulation of the Effects of Acoustic Noise on MEMS Gyroscopes

Abstract

Recent advances in MEMS technology have resulted in relatively low cost gyroscopes and accelerometers. The low cost of these devices has led to inexpensive inertial measurement systems, opening up a wide variety of possible applications for inertial measurement units (IMUs) with environmental conditions ranging from mild to harsh. This study focuses on MEMS gyroscopes, which are based upon vibratory, rather than rotational designs, that have been proven susceptible to the effects of acoustic noise. In some aerospace environments this is particularly true. In these environments the noise levels can reach higher than 120 dB with frequencies reaching in excess of 20kHz. These effects can overwhelm the output signals causing them to become extremely contaminated and even completely saturated. A model is developed to simulate testing the gyroscope exposed to high frequency noise. The model also simulates the use of several types of acoustic foams to mitigate the effect of high frequency noise. The model simulates high frequency noise as high frequency vibration. Samples of the foams will be tested to determine their ability to mitigate simulated high frequency noise. The information gathered from these tests will be used in the model to mitigate the effects of the high frequency acoustic noise simulated by use of high frequency vibration applied to the gyroscope in the model. Following testing with the model, several ADXRS300 gyroscopes were tested in an acoustically harsh environment to determine the effects of the high frequency acoustic noise. The foams were also tested to provide data to validate the model.