  An algorithm for pose and motion estimation using corresponding features in
images and a digital terrain map is proposed. Using a Digital Terrain (or
Digital Elevation) Map (DTM/DEM) as a global reference enables recovering the
absolute position and orientation of the camera. In order to do this, the DTM
is used to formulate a constraint between corresponding features in two
consecutive frames. The utilization of data is shown to improve the robustness
and accuracy of the inertial navigation algorithm. Extended Kalman filter was
used to combine results of inertial navigation algorithm and proposed
vision-based navigation algorithm. The feasibility of this algorithms is
established through numerical simulations.
