Indoor Positioning by Multiple Smartphones for Roll-call System with Seating Information

Accurate Indoor Positioning System (IPS) of all smartphones in the classroom is proposed. All smartphones transmit and receive beacon signals each other simultaneously and measure many RSSIs. A IPS server computer collects all RSSI information and estimates relative positions of smart phones, also absolute positions. The information of presence of students and their seating positions is provided to the lecturer. This paper shows the accuracy of the seating position estimation. Furthermore, compensation method of receiving sensitivity bias is proposed and applied.