System and algorithms for accurate indoor tracking using low-cost hardware

In this paper we present a novel radio location system for indoor tracking and navigation. The system has been designed for applications such as emergency first responders where high accuracy is required, all nodes have only wireless connections, and the system must be able to be rapidly deployed. The application requirements are best satisfied using time-of-arrival based radio location, however the challenge is to do this at low cost. Specific issues addressed by the system include achieving frequency and time synchronization using low cost oscillators in each node and overcoming the variable propagation delay in the analog electronics from the use of low cost radio components, while operating in an environment characterized by strong multipath interference. Our approach has been to use low cost highly integrated electronic components and to use sophisticated signal processing to compensate for the limitations in the radio electronics. The system has been implemented and we demonstrate a median error of 0.15 m outdoors and 0.49 m in an indoor office environment with measurements performed through multiple walls.