A Hybrid Wireless Positioning Technology Research

In recent years, with the development of mobile service, people not only pay attention to telephone service in the mobile communications,but also to pay close attention to the more abundant service function and various value-added services. Among them, using cellular mobile telephone network to locate the mobile user is a broad prospects mobile service.The basic principle of cellular nets wireless localization service use the existing cellular network to measure and estimate various characteristic parameters of positions to realize the mobile user's positioning. In the various basic algorithm of the wireless localization method, TDOA localization algorithm is most frequently used. This paper introduces three TDOA typical localization algorithms: Fang algorithm, Chan algorithm and Taylor series expansion algorithms, and compare the simulation performance of them in different channel environment.Because of channel noise, none line of sight transmission of signal and multipath interference, all sorts of position of characteristic parameters measurement and estimation can appear larger error, so, cellular wireless location system is hard to locate the user location accurately. Time reversal technology is a kind of new space channel matching technology, which has focusing characteristics of space and time. In the different channel, impulse response is generally not related or weak related, so using the characteristics of time reversal technology to overcome channel noise, none line of sight transmission of signal and multipath interference has a unique advantage. This paper presents a wireless localization method which is based on the time reversal technology, it take the pulse width of different channel impulse response's correlation function as the characteristic parameters to measure distance between mobile user and base station, and then combine with the traditional TDOA algorithm, this algorithm can get a mobile user's position more accurately. The system simulation of the wireless localization method was introduced in this paper, which is based on the Time reversal technology .The result of simulation shows that in the situation of channel noise, none line of sight transmission of signal and multipath interference, the wireless localization method which is based on the time reversal technology have better localization performance.