Design&Research Of Location System Base On WSN With ZigBee

The location information of a sensor node is very important, when wireless sensor networks applies to many different situations, such as environmental monitoring, ecological research, aircraft design, target surveillance. Many other services are based on their locations and only when the data bundles with the location information, it makes sense. The in-depth study of positioning technology in the wireless sensor network has a very important practical significance. This paper realized the design of wireless sensor network positioning system based on Z-STACK and CC2430/1by analyzing the ZigBee technology, wireless sensor network technology and the RSSI ranging technology. The main work includes many parts like the analysis of wireless sensor network’s protocol stack Z-STACK, the networking program design based on Z-STACK, the hardware design and implementation of the sensing nodes, design and improvement of the positioning process algorithm. The hardware part includes the design of ZigBee blind nodes, gateway nodes, the reference nodes’schematic and PCB diagram. In the positioning process, it includes two algorithms that are the ranging algorithm and positioning algorithm. Currently, the defects like low positioning accuracy, poor resistance to environmental interference and low positioning resolution are really there in the wireless sensor networks. In order to improve these problems, to the ranging algorithm, this paper proposes the use of the method of least squares curve fitting to build real-time ranging model. Also, the paper studies four methods which are the mean filter model, Gaussian filter model, Kalman filter model and the correction model based on the distance between the fixed beacon nodes, to correct the RSSI value respectively. The experimental results show that the Kalman filter model can achieve optimal estimation of the RSSI value, and better improve the accuracy of distance measurement. In addition, fragmentation process of ranging algorithm can be realized by combining the link quality indication (LQI) that is introduced with the RSSI.Finally, the system should be tested and analyzed. According to the test results, compared the positioning effect of the system that based on the above research design with a traditional one that based on the hardware location engine, the former one has a significant improvement in some respects such as ranging accuracy and anti-jamming capability.