Davide Scaramuzza and pals in the Robotics and Perception Group at University of Zurich have devised a new method called Semi-Direct Monocular Visual Odometry for autonomous gps denied micro areal vehicle navigation. Using only a single downward-looking camera in combination with an Inertial Measurement Unit the team was able to achieve robust autonomous navigation with fast vehicle state update frequency and low cpu cost. The high frame-rate tracking allows the filter to converge even in scenes of repetitive and high-frequency texture (e.g., asphalt, grass), as it is best demonstrated in the video.
A video of their work in action:
The paper can be read here http://rpg.ifi.uzh.ch/docs/ICRA14_Forster.pdf
Open source code https://github.com/uzh-rpg/rpg_svo