Efficient Terrain-Aided Visual Horizon Based Attitude Estimation and Localization

Inertial Navigation Systems typically rely on aiding-sensors such as GPS (Global Positioning System) to estimate the location of the system. The navigational performance of the Inertial Navigation System can be severely degraded when the GPS measurements are inaccurate or unavailable. Terrain-Aided Navigation is another method of localizing the platform by correlating the measured terrain information with a Digital Terrain Model. This paper presents an efficient Terrain-Aided Navigation method of generating position measurements from the visual appearance of the horizon profile (and hence terrain) surrounding the platform. An optimization process is used to align the measured horizon profile to an off-line pre-generated terrain-aided reference profile which allows for efficient position and attitude estimation. Numerical simulations are presented to evaluate the effectiveness of the proposed method. These results show that precise real-time attitude and position estimation is achievable using visual horizon profile information.