Research on Static Decoupling Method of Non-Gyro Micro Inertial Measurement Unit

In a non-gyro micro inertial measurement unit (NGMIMU), the coupling error reduces the system measurement precision obviously. Based on the definition of the coupling error, a new static decoupling method applied total least squares (TLS) algorithm is proposed. TLS considers not only the error of accelerometer output, but also the calibrating error of the input signal arising from the couple factor. Based on TLS, the solution of the coupling coefficient equation has the characteristic of minimum norm to the input and output values. In the navigation parameter estimation, according to the relationship of the accelerometer input and output value, the accurate estimated input value can be acquired through fitting the couple coefficient matrix using TLS and reconstructing the input value using Moore-Penrose generalized inverse matrix. A simulation case for estimating angle rate is investigated by this approach. The results show that the ratio of decoupling error is less than 8% and verify the feasibility of the static decoupling method.