Enhancing Exploration in Topological Worlds with a Directional Immovable Marker

One approach to answering the `loop-closing´ problem in embedded topological worlds is through the use of an external marking aid that can help the robot disambiguate otherwise identical locations. It has been shown in [1], [2], [3] that a single immovable directional marker is sufficient to solve loop closing, although at significant exploration cost (O(m²n) worst bound). Here we provide optimizations to the earlier algorithm and demonstrate improved exploration cost on a range of different topological worlds.