Despite advancements in the industry, safety investments at small construction sites remain underinvested due to budget constraints that limit the employment of safety managers. The results of this study explore a cost-effective solution for accurate positioning of workers in hazardous areas using off-the-shelf smartphones and Ultra-Wide Band (UWB) technology, with a focus on small and medium-sized construction sites. We targeted a Three-Dimensional (3D) positioning error of less than 35 cm in an indoor space of 25–50 m². The results show that the spatial configuration of anchors and Mobile Terminals (MTs) has a significant impact on 3D accuracy, and in particular, deployment strategies with increasing height differences show a clearer reduction in error than differences in positional accuracy caused by differences between general least square algorithms. This highlights the importance of optimal anchor-MT placement, similar to Global Navigation Satellite System (GNSS) standards, to minimize Position Dilution of Precision (PDOP) values and improve positioning accuracy. We also suggest that adjusting the tetrahedral volume formed by anchors and MTs can solve complex site problems,improve worker positioning, and benefit safety management. This approach presents a practical and scalable way to improve safety protocols on small construction sites.

This study presents an integrated smart construction monitoring system that combines point cloud data (PCD) from a 3D laser scanner with real-time IoT sensors and ultra-wideband (UWB) indoor positioning technology to enhance construction site safety and quality management. The system addresses the limitations of traditional BIM-based methods by leveraging high-precision PCD that accurately reflects actual site conditions. Field validation was conducted over 17 days at a residential construction site, focusing on two floors during concrete pouring. The concrete strength prediction model, based on the ASTM C1074 maturity method, achieved prediction accuracy within 1–2 MPa of measured values (e.g., predicted: 26.2 MPa vs. actual: 25.3 MPa at 14 days). The UWB-based worker localization system demonstrated a maximum positioning error of 1.44 m with 1 s update intervals, enabling real-time tracking of worker movements. Static accuracy tests showed localization errors of 0.80–0.94 m under clear line-of-sight and 1.14–1.26 m under partial non-line-of-sight. The integrated platform successfully combined PCD visualization with real-time sensor data, allowing construction managers to monitor concrete curing progress and worker safety simultaneously.

This erratum is published to notify a replacement of Table 6 in the original article.