Indoor tracking of construction workers using BLE: Mobile beacons and fixed gateways vs. Fixed beacons and mobile gateways

Automatic resource location monitoring in construction projects empowers managers to make data driven decisions that improve project workflow. Monitoring data can be processed to measure workflow quality and thus for better understanding of effectiveness and efficiency. We compare two methods for deployment of Bluetooth Low Energy (BLE) beacons for indoor resource monitoring - mobile beacons and fixed gateways (MB) vs. fixed beacons and mobile gateways (FB). BLE beacons can be fixed to walls or carried by workers, and can be fixed to material containers and equipment. Using gateways, such as raspberry pi computers or smartphones, one can easily and automatically monitor resource locations. Several field experiments were conducted, both in the laboratory and in construction sites in Finland, Israel, Peru, Netherlands and China. Technical aspects such as setup, direct cost, feasibility and accuracy were compared for two methods - mobile beacons and fixed gateways vs. fixed beacons and mobile gateways - and the performance of each method in providing the data needed for lean construction workflow assessment was assessed. Both methods are effective in monitoring resource locations but differ in their feasibility of implementation in construction sites and in the utility of the data they provide in terms of identifying value adding activities.