Vision-only UAV navigation aided by terrain elevation map

A vision-only navigation system is addressed for autonomous navigation of unmanned aerial vehicles (UAVs) with monocular camera as the only sensor. Typical vision-based navigation algorithms blend inertial navigation data with vision measurements and other available information to estimate vehicle´s position. In this paper, however, we propose an approach that replaces the high-cost inertial navigation system by a translational motion estimate obtained by the camera. This method shares a concept of terrain referenced navigation (TRN) in that the height measurements by camera are compared to terrain data to construct an observation model. The particle filter based on Bayesian tracking is employed to combine the translation estimate and measured heights of feature points which contain unknown correlation. Numerical simulations are conducted to verify the feasibility of the proposed method.