Wi-Fi Group Monitoring System Using Free Space Propagation Model with Active Scanning

In these few years, Wi-Fi technology is widely used for indoor localization to overcome the limitation of global positioning system (GPS) accessibility within the indoor environment. The GPS accuracy is affected with an approximated error rate of 5 to 10 meters because the GPS signal will decrease while penetrating through the building walls or obstacles. This paper describes a low-cost and simple development of a group monitoring system with a single Wi-Fi access point using Raspberry Pi. Distance estimation methods based on the free-space propagation model and received signal strength indicator (RSSI) are implemented. The received signal strength indicator is collected during active scanning for indoor group monitoring in public spaces, such as shopping malls, retail shops, airports, railway stations, hotels, etc. A Group monitoring system with Wi-Fi active scanning opens the possibilities for the utilization of a single Wi-Fi access point to analyze the distance estimation for multiple audiences within the indoor public spaces. The functionalities of the proposed system include device detection, distance estimation, group monitoring, and social distancing alert.