Estimating MEMS gyroscope g-sensitivity errors in foot mounted navigation

Errors in gyroscope measurements due to linear accelerations are often overlooked in foot mounted navigation systems. Accelerations of foot mounted IMUs can reach 5 g while walking and 10 g while running, but vary depending on the sensors location and mounting. These accelerations are often very short and can induce large biases in the gyro which can produce attitude errors when the measurements are integrated. This paper proposes a real time method for the mitigation of g-sensitivity errors whereby the coefficients are estimated in the navigation Kalman filter. Variations of the estimation scheme are given including estimating the diagonal terms of the 3×3 matrix or all nine elements of the matrix. Accuracy (RMS) improved by 45% and 61% in two data sets using two different sensors in different environments. Convergence rates of the estimated variance are also shown.