In this section we describe a system for localization on Earth given measurements of Sun altitude. This problem, known to ancient civilizations, is part of the basic knowledge of any sea navigator. Celestial information has been used in space applications for attitude control and accurate positioning [16]. Yet celestial navigation has not been heavily mentioned in connection with autonomous rovers. This comes as a surprise since planetary rovers will not be connected with GPS or similar localization systems and will need reliable means of checking dead reckoning data.
The localization system described here is based on a camera with telephoto lenses. Our purpose was to validate the idea of celestial localization through image processing.
The usual procedure in marine applications is to get several altitude measurements from different stars and to determine position from them. We will modify this problem by tracking only the Sun over time; the result will be equivalent to obtaining several star measurements simultaneously.