Study Of A New Algorithm For TDOA Localization Mechanism Based On Cellular Networks

With a large-scale development of mobile communication technology and the application and popularization of 3G networks, including WCDMA,CDMA2000 and TD-SCDMA in China, the wireless terminal localization technology based on cellular system has been getting more and more urgent needs and increasingly high performance requirements, also many research achievements have arisen in the practical application. The terminal localization technology based on cellular communication system has many uses, not only provides a positional information service for terminal users, urgent rescue for missing situation and goods tracing function, on the other hand, it has also played a very effective role in national security and crime prevention. A new algorithm for TDOA localization mechanism is studied based on cellular networks in this paper in order to provide more accurate and more reliable location result for the applications mentioned above.The basic principle of the terminal localization technology and its application in cellular communication system will be introduced firstly. And then, this thesis introduces the basic principle for TDOA localization algorithm, the mathematical wireless model of the cellular networks and the evaluation standards and methods for position performance. In this thesis, the mathematical model of TDOA hyperbolic equations was built and the major existing basic location algorithms at home and aboard were investigated and compared under perfect channel environment and common mobile channel environment, including Chan algorithm, Friedlander and Taylor sequence method of development and so on which are based on TDOA location algorithm. And then this thesis will concentrate on the core issues that traditional methods can not guarantee the reliability of accuracy under non line of sight transmission situation. On the base of Chan algorithm, other algorithms which can improve positioning reliability are analyzed in NLOS environment. The Taylor series expansion method as an iterative method has higher accuracy, as a follow-up method to Chan's algorithm to optimize algorithm accuracy. Finally, simulations of the location algorithm are made and the result indicates that the performance of the proposed position methods is improved effectively. The analysis results indicate that the new algorithm for TDOA localization mechanism proposed in this paper can provide better location results under NLOS channel environment. The RMSE of location error is reduced greatly, which will promote the development of mobile communication technologies and the application of the third generation network in the future.