Unified All-Earth Navigation Mechanization and Virtual Polar Region Technology

For a strap-down inertial navigation system (SINS), a traditional navigation frame switching mechanization can be used to solve the all-Earth navigation problem, however, this kind of method suffers from complex and discontinuous algorithms. On the basis of improving vertical channel damping technology, a complete and unified all-Earth navigation scheme arranged in the Earth-centered Earth-fixed (ECEF) frame is designed as an alternative for global applications, which results in a simpler continuous algorithm and lower computational complexity. We also propose a virtual polar region technology based on the grid attitude and velocity invariant method (G-AVIM), which can complete the polar navigation verification through the actual test data of nonpolar regions. In the reconstructed polar region trajectory, the vehicle attitude, velocity, and height information relative to the ground remain unchanged, so the real test environment can be completely reproduced in the polar region. Simulations and field test results verified the proposed methods.