PreAct-Nav: Agentic Reasoning Before Action for Urban Navigation
This study addresses the limitation of existing agent navigation systems in translating long-term goals into coherent local decisions, particularly their lack of foresight regarding action consequences and future states. To this end, we propose PreAct-Nav, a framework that equips agents with anticipatory reasoning and error-correction capabilities under a frozen policy. Specifically, the method constructs a predictive world sandbox using an Action-Conditional World Model (AC-WM), leverages Vision-Language Models (VLMs) to anchor mid-range subgoals for reasoning, and introduces a persistent memory module to enable dynamic updates. Experimental results demonstrate that PreAct-Nav significantly improves action selection accuracy in long-distance, multi-turn scenarios and enhances navigation robustness within complex urban environments.