A positioning system utilizes ZigBee™, a wireless sensor network on the 2.4-GHz ISM band. The technology applies stochastic reasoning in analyzing the ID and received signal strength indication (RSSI) of received wireless signals. Due to multipath interference, the position of people or target objects can be estimated within a margin of error of one to several meters, regardless of signal loss, noise, or signal fluctuation.The emergency signal transfer system, which was demonstrated in commercial buildings, can alert and guide users to the nearest emergency exit by means of mobile phones. Other applications of the technology include positioning users, robot movement support, and determining conditions of indoor environments. The system has been installed and tested at Landmark Plaza in Yokohama City, Japan.