The Study Of Positioning And Tracking Of Moving Objects Based On ZigBee

In recent years, short-range indoor location is widely concerned, a variety of corresponding locating methods emerge constantly. However, indoor locating technique also needs further research and improvement because of different applications, power consumption, interference and communicated costs. With the characteristics of low price and low power consumption ZigBee technology which has been launched recently occupies a certain advantage in the market. Many companies have introduced ZigBee wireless locating solutions. July 2007, Texas Instruments(TI) announced the launch of the chip CC2431 which is the first chip on system(SoC) solution with hardware positioning engine. The emergence of the chip makes localization algorithm implement through the hardware. Commercial positioning systems based on CC2431 emerge in large numbers.In this paper, we studied the architecture of wireless sensor network and the TI Z-stack protocol stack in detail. First of all, we studied the method of distance measurement which is based on RSSI and the establishment of the mathematical model. Then we implemented two location algorithm simulation which we often called trilateral measuring method and maximum likelihood estimation using MATLAB. Next, a positioning system based on CC2431/CC2430 has been designed and the software of various nodes has been developed, we measured and set parameters for indoor environment and outdoor environment and then coordinators were measured and compared with the actual value. We also compared the measured coordinators for ideal outdoor environment with the MATLAB simulation of two kinds of localization algorithm. At last, we wrote a PC monitoring software with VC++ 6.0, which could realize wireless configuration and real-time dynamic monitoring the state of each node.Though simulation and actual system measurements showed that the accuracy of the system which is based on CC2431 distributed positioning method is slightly lower than the simulation of trilateration and the maximum likelihood method, the accuracy is also reached 1 metre. The system meets the basic needs of a positioning system,such as low power dissipation, low cost and easy to realize and so on. At the end of the article, we gave the summary and outlook of the article and proposed the inadequacies of the article and looking to the future research direction.