Map Validation and Self-location in a Graph-like World

We present algorithms for the discovery and use of topological maps of an environment by an active agent (such as a person or a mobile robot). We discuss several issues dealing with the use of pre-existing topological maps of graph-like worlds by an autonomous robot and present algorithms, worst cases complexity, and experimental results (for representative real-world examples) for two key problems. The rst of these problems is to verify that a given input map is a correct description of the world (the validation problem). The second is to determine the robot's physical position on an input map (the self-location problem). We present algorithms which require O(N) and O(N) steps to validate and locate the robot in a map (where N is the number of places in the map). This paper appears in the Proceedings of IJCAI 1993, Chambery, France, August 1993. Financial support from NSERC Canada, and the Ontario-Quebec interchange program is gratefully acknowledged. We also thank Xiaotie Deng and Andy Mirzaian for many helpful discussions.