Feasibility study on smartphone localization using mobile anchors in search and rescue operations

This paper presents a feasibility study on smartphone localization of missing persons in Search And Rescue (SAR) operations using widely available Commercial-Off-The-Shelf (COTS) products. We assume (1) that the missing person wears an enabled smartphone and (2) that messages transmitted by this smartphone can be intercepted by mobile agents at known positions. We present a proof-of-concept that consists of several mobile agents carrying smartphones that measure the Received Signal Strength (RSS) of Wi-fi messages transmitted by the smartphone of the missing person. The positions of the mobile agents are determined using the GPS unit on the smartphones. The mobile agents send the collected RSS and GPS data to a central processing unit. The central processing unit processes the data in real-time and guides mobile agents in SAR operations to the missing person by estimating its position. Our central processing unit runs a localization algorithm that requires no calibration. This is a necessary condition for resue operations that usually take place in unknown environments with unknown hardware. Our experiments in an 250×130m2 outdoor field shows that our localization system provides an average localization performance of roughly 15 meters, which is sufficient for most SAR operations of interest. In addition, we performed several successful tests with a Quadcopter to show the feasibility of using unmanned vehicles in SAR operations.