In-flight initial alignment scheme for radar-aided SINS in the arctic

This study proposes a novel in-flight initial alignment scheme for the strapdown inertial navigation system (SINS) in the Arctic, aiming to solve the attitude divergence problem caused by the inherent SINS error characteristics. Considering the special geographical conditions in the Arctic, the authors establish the SINS mechanisation equations and radar equations in the grid frame in this work. In the coarse alignment stage, the radar information is employed to solve the nonlinear equations by using the multi-population genetic algorithm (MGA), and then the unscented Kalman filter is applied to diminish the noise influence on MGA results. During the fine alignment process, the attitude information is further corrected by the Radar/SINS integrated navigation system under the Arctic coordinate frame. At last, numerical simulations are performed, and the results demonstrate that the proposed scheme achieves better accuracy compared with traditional approaches.