A Dual-Antenna GNSS-Assisted Low-Cost SINS Initial Alignment Method Based on ASTKF

The low-cost strapdown inertial navigation system (SINS) gyroscope cannot accurately sense the rotation angle rate of the earth, and cannot achieve accurate self-alignment of the heading angle, other equipment is needed to achieve initial alignment. This paper proposes a dual-antenna Global Navigation Satellite System (GNSS)-assisted rapid alignment method. An attitude measurement model is derived based on dual-antenna GNSS. The determined attitude information has the advantages of short initial time and no accumulation of errors over time. Dual-antenna GNSS can provide velocity, the position and attitude information for initial alignment. When the measurement noise distribution deviates from the predicted Gaussian distribution and the noise covariance matrices in the filtering model are incorrect, existing linear state estimators may not always operate satisfactorily. Combined with the precise information provided by dual-antenna GNSS, extending the study of a novel adaptive Student’s t-based Kalman filter (ASTKF) based on updating the initial attitude matrix to suppress the divergence of attitude angles to overcome these problems. The suggested method outperforms current initial alignment techniques in terms of alignment speed and accuracy, according to experimental simulation results.