Abstract. In this paper a set of physical properties is presented that can be utilized for save and efficient navigation in unstructured terrain. This set contains properties of positive obstacles, i.e. flexibility, shape, dimensions, etc. as well as properties of negative obstacles and ground, i.e. slope, carrying capacity, slippage, etc. By means of these properties a classifier is developed that supports the discrimination from traversable to non-traversable areas. Furthermore, an overview of different sensor systems, that can be employed to determine some these properties, is given.