Planet surface simulation for testing vision-based autonomous planetary landers

ESA is planning a series of robotic missions to Mars, the safe delivery of which will be greatly assisted by landing systems capable of autonomous navigation and hazard detection and avoidance. Vision-based navigation is a promising technique which is currently being developed by ESA. The testing of vision-based navigation systems can benefit from computer-based planet surface simulations representative of the target planetary body. PANGU (Planet and Asteroid Natural Scene Generation Utility) is a software tool for simulating and visualising the surface of various planetary bodies. PANGU builds a planet surface model starting with a predefined surface or a fractal surface generated by PANGU. Craters are placed on the terrain according to user defined parameters, combining idealised mathematical models with fractal techniques to produce a realistic appearance. Boulders, sand dunes and other small scale features may then be added. Given the position and orientation of a camera, PANGU generates the corresponding image accounting for illumination conditions. PANGU has been designed to give a high degree of realism while operating at near real-time speeds. As well as cameras, scanning LIDAR and radar altimeters may also be simulated, allowing a comprehensive evaluation of various navigation sensor combinations and redundancy schemes for planetary landers.