The Attitude Determination Algorithm using Integrated GPS/INS Data
| Authors: | Huang Yi-Min, National Taiwan University, Taiwan
Chang Fan-Ren, National Taiwan University, Taiwan
Wang Li-Sheng, National Taiwan University, Taiwan |
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| Topic: | 6.4 Safeprocess |
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| Session: | Applications of Fault Detection and Isolation |
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| Keywords: | attitude algorithms, gyros, extended Kalman filters, quaternion, SLERP |
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Abstract
Traditionally, the extended Kalman filter (EKF) is a well known approach for general nonlinear data fusion problem. But the unit norm constraint of quaternion vector, which is the most efficient expression of attitude, results in the singularity of error covariance matrix. To overcome this difficulty, the modified extended Kalman filter (MEKF) has been developed by Shuster (1982). In order to improve the computational complexity of MEKF, we introduce the concept of spherical linear interpolation (SLERP). SLERP is a simple approach when two quaternions are averaged according to their accuracy dependent weightings. The SLERP based MEKF is proposed in this paper. However, its shortcoming is that the SLERP based MEKF cannot estimate gyro bias. Hence the proposed approach is not appropriate for the long duration navigation. The trade-off of MEKF and the SLERP based MEKF is discussed also.
