A novel high-precision transfer alignment method for shipborne aircraft at arbitrary parking positions and directions

The parking position and direction of shipborne aircraft on the deck are not fixed. Meanwhile, due to complex sea conditions, the ship dynamically sways all the time. Therefore, there is always a relatively large difference in attitude and position between ship's main inertial navigation system (INS) and shipborne aircraft's slave INS. This will seriously affect the accuracy of shipborne aircraft's transfer alignment. To this end, a novel high-precision transfer alignment method for shipborne aircraft's INS is proposed. The inherent relationship between main and slave INSs’ angular velocities, attitude angular deviation and relative position is revealed. Then, real-time dynamic tracking of attitude angular deviation and relative position is realized by using angular velocities output from main and slave INSs (main-slave INSs). Furthermore, the measurement models between main-slave INSs’ attitude difference, velocity difference, attitude angular deviation, relative position, and slave INS's navigation errors are derived. Then, the measurement variables are constructed by using the attitude angles and velocities output from main-slave INSs. In this way, the tracking errors of attitude angular deviation and relative position can be estimated and corrected in real time by Kalman filtering algorithm. Meanwhile, the precise estimation of slave INS's misalignment angle can be realized. Finally, the verification results indicate that, compared with the traditional methods, the alignment accuracy of the proposed method can be improved by over 71.27%. Thus, the high-precision alignment of shipborne aircraft at any parking position and direction can be achieved.