A Polar Rapid Transfer Alignment Assisted by the Improved Polarized-Light Navigation

The polar rapid transfer alignment (RTA) is preferred to initialize the moving base. The heading error under the grid frame accumulates with time, and the aid to navigation is required to calibrate the strapdown inertial navigation system (SINS). However, the Arctic has a complex environment where auxiliary navigation devices, customarily used in low and medium latitudes, cannot operate appropriately in polar regions. The SINS attitude reference may contain errors to contaminate the measurement quality of RTA, causing alignment failure. Thus,we introducedpolarized-light navigation to offer the heading and assist attitude matching. However, its heading error is associated with the longitude error amplifiedwith increasing latitudes, and the outputs from systems are not unified into an identical navigation frame. For success in initialization at high latitudes, this work innovatively proposed a polar rapid transfer alignment assisted by the improved polarized-light navigation. Firstly, the grid heading of the polarized-light navigation was redefined under the grid frame, and the proposed weighted-clustering algorithm was used to process the skylight polarization pattern and extract the angle out. Eventually, we established the mathematical model of RTA with disturbances and augmented the grid heading solution from the polarized-light navigation into measurements, solving the low-quality attitude reference of the master SINS. Simulations and semiphysical experiments demonstrated that the proposed algorithm performed better, and the estimate error approached only several minutes of arc when the master attitude reference had over 1-degree attitude error.