Title: TrajFlow: Nation-wide Pseudo GPS Trajectory Generation with Flow Matching Models
Primary area: generative models
Keywords: Flow matching, Human Trajectory, Generative modeling, Human mobility

Abstract: The importance of mobile phone GPS trajectory data is widely recognized across many fields, yet the use of real data is often hindered by privacy concerns, limited accessibility, and high acquisition costs. As a result, generating pseudo–GPS trajectory data has become an active area of research. Recent diffusion-based approaches have achieved strong fidelity but remain limited in spatial scale (small urban areas), transportation-mode diversity, and efficiency (requiring numerous sampling steps). To address these challenges, we introduce TrajFlow, the first flow-matching–based generative model for GPS trajectory generation. TrajFlow leverages the flow-matching paradigm to improve robustness across multiple geospatial scales and incorporates a trajectory harmonization & reconstruction strategy to jointly address scalability, diversity, and efficiency. Using a nationwide mobile phone GPS dataset with millions of trajectories across Japan, we show that TrajFlow consistently outperforms diffusion-based and deep generative baselines at urban, metropolitan, and nationwide levels. As the first nationwide, multi-scale GPS trajectory generation model, TrajFlow demonstrates strong potential to support inter-region urban planning, traffic management, and disaster response, thereby advancing the resilience and intelligence of future mobility systems.

TL;DR: This paper proposed TrajFM, a flow-matching-based GPS trajectory generation model that overcomes scale, diversity, and efficiency limitations of diffusion approaches to enable nationwide, multi-scale, and multi-modal human mobility data generation.