Map Drawing Based on a Resource-Constrained Search for a Navigation System

Abstract

In this paper, we propose a map drawing method based on route-finding for a navigation system. To find a route, repeated searches expand branches from the current node to successive nodes until the goal node is reached. When the search space resulting from this process is drawn on a two-dimensional plane, we can regard it as a route map to a goal. We applied our method to a palm-top navigation system and developed a Resource-Constrained Heuristic Search (RCS) for making a route map. This allows us to set the memory and computing time limitations in advance. Palm-size PCs generally have insufficient memory to store entire maps on a practical scale and consequently must resort to downloading at the limited speeds typical of cellular phone communication. Thus, if we set a memory limitation, it can generate a map within the limited memory size; if we set a time-limit, it can achieve not only real-time route finding but also real-time map drawing. We implemented a palm-top navigation system that displays the current position on a map produced by the Global Positioning System (GPS) on a palm-size PC. Our experiment demonstrates that a route map generated by our RCS is sufficient for us to reach a goal along a designated route.