A Wireless Sensor Network Localization System Based On Zigbee

Localization is a basic function of wireless sensor network. By these years, many people have studied about it. Most of them just stopped on the theory stage. But to the special study object WSN, simulation may be very far from the reality. Some of these questions must be solved in the experiments. So we want to build a real system, which can change the theory into reality. We can also test the theories by it.About localization of WSN based on ranging, there are many methods. we choose ultra because it has good directivity and accuracy. Crossbow hardware test bed componets (including Mote, sensor board, Gateway. etc )make up a low power consumption application module. Its low cost and high efficiency makes that it's proper to be used to build a network. We compose a Node, the hardware Node in the test bed, with WSN Mote and SRF08 in a brand new way. And we connect Micaz and SRF08 with I2C interface supplied by TinyOS, to make a new interface Sonarcmd. We also compared the localization algorithm by simulation. After Modified, extended kalman filter (EKF) is better than least square method.We do research in a tracking system based on IEEE 802.15.4 and ultrasonic sensor devices, and then we present a small test bed, good user-machine interface, extended kalman filter applied in state estimate. This application deals with the core problem in indoor localization of wireless sensor network. That really benefits to communication of smart home, safety and protection.