Robust Initial Attitude Alignment for SINS/DVL

The attitude determination (AD) based initial alignment for Doppler velocity log (DVL) aided strapdown inertial navigation system (SINS) is investigated. Three issues involved in practical applications are pointed out and addressed, which have not been discussed in previous works. First, the explicit AD-based initial alignment procedure is presented for DVL-aided SINS with the consideration of different sampling frequencies of the two devices. Second, an outliers detection and isolation procedure for DVL is proposed based on the fact that the transverse or up speed is always near zero. Third, it is pointed out that the constructed vector observations should be normalized when used in the AD. The validity and superiority of the proposed methods are demonstrated through an experimental study.