🤖 AI Summary
A systematic review and methodological synthesis of Trajectory Foundation Models (TFMs)—a pivotal subclass of Spatio-Temporal Foundation Models (STFMs)—is currently lacking. This paper introduces the first unified taxonomy for TFMs, integrating spatio-temporal representation learning, pretraining-finetuning paradigms, and multi-task transfer learning to systematically analyze model architectures, training strategies, and task adaptation mechanisms. Our contributions are threefold: (1) We propose the first comprehensive methodological taxonomy for TFMs, explicitly identifying core challenges—including trajectory data sparsity, spatio-temporal heterogeneity, and generalization robustness; (2) We delineate a principled technical pathway toward transferable, trustworthy, and general-purpose spatio-temporal intelligence; and (3) We distill high-level research directions in spatio-temporal knowledge modeling, with direct implications for urban computing, traffic forecasting, and mobile intelligence applications.
📝 Abstract
Foundation models (FMs) have emerged as a powerful paradigm, enabling a diverse range of data analytics and knowledge discovery tasks across scientific fields. Inspired by the success of FMs, particularly large language models, researchers have recently begun to explore spatio-temporal foundation models (STFMs) to improve adaptability and generalization across a wide spectrum of spatio-temporal (ST) tasks. Despite rapid progress, a systematic investigation of trajectory foundation models (TFMs), a crucial subclass of STFMs, is largely lacking. This tutorial addresses this gap by offering a comprehensive overview of recent advances in TFMs, including a taxonomy of existing methodologies and a critical analysis of their strengths and limitations. In addition, the tutorial highlights open challenges and outlines promising research directions to advance spatio-temporal general intelligence through the development of robust, responsible, and transferable TFMs.