Research on improving the north-seeking precision of MEMS gyroscope

Abstract

In order to improve the north-seeking precision of the micro-electro-mechanical system (MEMS) gyroscope, it is necessary to measure the earth’s rotation angular velocity accurately. The output precision of the MEMS gyroscope is affected by zero bias, installation error, scale factor error, etc. Aiming at the problem of the low output precision of the MEMS gyroscope, this paper mainly studies the test method of the MEMS gyroscope scale factor. In this study, the north-seeking principle of the MEMS gyroscope is analyzed, and the equivalent relationship between scale factor error and angular rate error is investigated. A Multi-Position ground velocity method is proposed for testing the scale factor of the MEMS gyroscope. In this method, the Earth’s rotation angular velocity component is used as the input of the MEMS gyroscope, and the scale factor is calculated by dual exponential fitting. The feasibility of the test method is verified by experiments on the rate turntable. The experimental results show that when the input angular velocity is between −0.0036° s−1 and 0.0036° s−1, compared with the traditional angular rate test method, the nonlinearity of the MEMS gyroscope scale factor tested by the proposed method is reduced from 227.45 ppm to 68.19 ppm, the asymmetry is reduced from 253.61 ppm to 73.65 ppm, and the north-seeking accuracy is improved 4.17 times, which verifies the effectiveness and superiority of the proposed method.