Terrain aided navigation based on SPKF

As a part of modern combined navigation system, Terrain Aided Navigation (TAN) estimates the location of the aircraft and further correct the errors of the Inertial Navigation System (INS) by comparing terrain height beneath the aircraft and the terrain height taken from onboard Digital Elevation Map (DEM). Currently TAN has been playing an important role in the modern navigation fields especially in military aviatic applications. The most popularly researched technique in the traditional TAN methods is Extended Kalman Filter (EKF), which actually cannot assure the optimal estimation because of the nonlinearity of terrain height measurement. Sigma-Point Kalman Filters (SPKF) is a family of improved derivativeness nonlinear Kalman filters. Due to its capability of solving the nonlinearity problem in estimation, a new TAN method based on SPKF is proposed. In experiment on real DEM dataset the SPKF achieves higher performance than EKF method, especially in the case of flat terrain character.