  Misalignment angle will result in a considerable error for the integration of
Doppler Velocity Log (DVL) and of Strapdown Inertial Navigation System (SINS).
In this paper, a robust initial alignment method for SINS/DVL is proposed to
solve a practical applicable issue, which is that the outputs of DVL are often
corrupted by the outliers. Firstly, the alignment principle for SINS/DVL is
summarized. Secondly, based on the principle of this alignment method, the
apparent velocity model is investigated, and the parameters expression of the
apparent velocity model are derived detailed. Using the apparent velocity
model, the unknown parameters of the apparent velocity model are estimated by
the developed Robust Kalman Filter (RKF), then the reconstructed observation
vector, where the outliers are detected and isolated, is reconstructed by the
estimated parameters. Based on the reconstructed observation vectors, the
initial attitude is determined. Finally, the simulation and field tests are
carried out to verify the performance of the proposed method. The test results
are shown that the proposed method can detect and isolate the outliers
effectively and get better performance than the previous work.
