Work has been undertaken at the University of Wales, Aberystwyth in the area of localisation and navigation of aerial vehicles (aerobots) in large unstructured environments (i.e. natural outdoors). The localisation and navigation method presented in this paper was developed for planetary exploration with an emphasis on Mars, but could also be used on Earth. Mars has an atmosphere, which is dense enough to allow the use of aerobots, and the Mars Orbiter Laser Altimeter (MOLA) [1][2] has provided the low resolution topographical map of the surface. The MOLA data [3] has provided the scenery for Flight-Gear [4] an open source flight simulator, which provided the environment within which all the localisation and navigation experiments have been conducted. Localisation and navigation has been achieved by extracting naturally occurring surface features (landmarks i.e. peaks, ridges, channels etc.) from the topographical maps. By categorising the surface by its features, then by matching these features in a high resolution topographical map, generated onboard the aerobot, with the same features in the low resolution global map, (e.g. MOLA data) a position estimate is obtained. Once the aerobot has localised, navigation to desired positions can be achieved using a combination of a feature path (feature navigation) and inertial navigation methods. This paper presents the results obtained from the localisation and navigation phases, from the point at which an aerobot obtains topographical maps of the surface, analyse them for features, estimates its position and orientation, to the point of navigating to the desired sites of scientific interest.
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