The effect of carouseling on MEMS IMU performance for gyrocompassing applications

Abstract

The concept of carouseling an IMU is simulated in order to improve the accuracy of MEMS IMUs. Carouseling consists of slewing the IMU through a pre-determined trajectory that is selected based on inherent properties that lead to improved performance. MEMS devices typically have far more uncertainty than standard inertial measurement devices, yet are considerably less massive and require less power, so implementing this carouseling scheme could make the use of these lightweight systems possible even in high-accuracy situations, such as gyrocompassing. In gyrocompassing, the most significant benefit provided by the carouseling scheme is the reduction in the error contribution of gyroscope bias, as this error is almost completely eliminated. Additionally, it was found that although implementing the carouseling scheme required the addition of error states to account for the size effect, in many cases these error states may not be necessary. Overall, the carouseling of the MEMS IMUs was shown to be effective in reducing azimuth error covariance significantly.