Indoor localization system for emergency responders with ultra low-power radio landmarks

In this paper we present a novel indoor localization approach based on 868MHz radio landmarks and inertial sensor data as a guidance system for emergency responders. For the first time we use low-power wake-up technology to develop real-time capable landmarks that overcome the problem of limited landmark lifetime. While in sleep mode our landmarks have an overall power consumption of 5.6μW making them ready-to-use in case of an emergency for up to 8 years. The landmarks are small and cost-efficient and may be integrated into the building infrastructure, e.g. into smoke detectors. Additionally, we have developed a handheld device for firefighters which communicates with our landmarks by an initial radio wake-up call and subsequent measuring of the received signal strength (RSSI) of the response. The measurements are used as an input to estimate and display the positions of the firefighter and the landmarks using local optimization algorithms. Furthermore, our handheld device communicates with a body-mounted wireless micro-inertial measurement unit (μIMU) to receive the angular rate, acceleration and magnetic field information in all three dimensions improving the accuracy of positioning. With this easy-to-setup guidance system emergency forces can be more effective, and the duration of rescue operations is reduced, hereby improving both the safety of rescue forces and increasing the chances of disaster victims.