Towards Near Real-time Digital Twins of Construction Sites: Developing High-LOD 4D Simulation Based on Computer Vision and RTLS

4D simulation can be used in the planning phase of a project for constructability analysis, which aims to optimize construction processes and improve safety management. The same 4D simulation can be used as a digital twin in the construction phase for progress monitoring and identifying potential safety issues based on micro-schedules. A micro-schedule is a schedule listing tasks of short durations (i.e., days or hours) with the information of the resources assigned to each task (i.e., workers, equipment and materials). The site data can be collected using Computer Vision (CV) or Real-Time Location Systems (RTLS) to identify and recognize the activities of construction resources, as well as to capture the progress of the project. This paper aims to explore the possibility of developing near real-time digital twins of construction sites. The digital twin is developed as a high Level of Development (LOD) 4D Simulation based on CV and RTLS data. A case study is performed to investigate the proposed method.