Visual odometry aided by a sun sensor and inclinometer

In this paper, we present a novel approach to localization for planetary rovers, in which sun sensor and inclinometer measurements are incorporated directly into a stereo visual odometry pipeline. Utilizing the absolute orientation information provided by the sun sensor significantly reduces the error growth of the visual odometry path estimate. The measurements have minimal computation, power, and mass requirements, providing a localization improvement at nearly negligible cost. We describe the mathematical formulation of error terms for the stereo camera, sun sensor, and inclinometer measurements, as well as the bundle adjustment framework for determining the maximum likelihood vehicle transformation. Improved localization accuracy is demonstrated through extensive experimental results from a 10 kilometre traversal of a Mars analogue site on Devon Island in the Canadian High Arctic.