Combined Terrain Aided Navigation based on Correlation Method and Parallel Kalman Filters

As an important part of modern integrated navigation system, terrain aided navigation (TAN) compares measured terrain height with the onboard digital elevation map (DEM) to locate a vehicle's position. However, traditional TAN methods cannot work robustly when flying over flat terrain. This paper proposes a combined terrain aided navigation (CTAN) system, which incorporates the correlation method with the parallel Kalman filters. In this system, both the correlation method and the parallel Kalman filters are utilized to calculate the position by analyzing the difference between the DEM data and the set of height measurements, which is collected in real time. Two obtained position are used to correct the possible estimation error, caused by the repetitive characteristic of terrain or the noise of measurements. Compared with the TAN system uses only the correlation method, simulation results approve the proposed system can significantly improve the navigation performance.