A Study on Observing a Lost Child Using BLE Beacons

In this paper, we mention the result of the experiment to observe a lost child by using BLE beacons. We performed a trial of a children observation service in June 2017 in a 5-story building. One or more children moved with BLE beacon. Some witnesses moved with a smartphone to detect a BLE beacon that was held by a child. Also, we used some fixed beacon to detect a position of witnesses. We prepared 19 test patterns to test the possible combinations of the position of a smartphone, status of the application (foreground or background), floors, the number of the lost children and witnesses to estimate the accuracy of location and floor of the lost child. As a result, the possibility to detect floor was 76.1%, and the possibility to detect the location on a floor was 78%. We would like to discuss the reason for the low accuracy and the plan for the next step as the conclusion.