| At present,mobile communication technology is growing rapidly,all kinds of mobile value-added services emerge in endlessly,of which the positioning applications represented by maps,navigation,and online games and so on are gradually becoming the research hotspot of the communication field.The nature of wireless location technology is to locate the moving targets by measuring parameters such as field intensity,propagation time and incident angle of radio signal.Mature development of GSM mobile communication network makes positioning technology based on GSM attract much attention.And this thesis also launches a series of research on it.Aiming at the non-line-of-sight propagation problem,corresponding solutions are put forward to improve the effect of positioning service.And the positioning experimental prototype designed in this thesis is used for positioning test in real environment.The main work in this thesis is as follows:1.This thesis analyzes the features and key techniques of GSM mobile communication system.The positioning scheme for GSM mobile phone is designed according to the characteristics of the GSM system.2.As the non-line-of-sight propagation problem existing in the process of positioning will cause the measuring error of TDOA and AO A,this thesis proposes Kalman positioning algorithm based on TDOA/AOA.By establishing the measurement error model of TDOA and AOA to refactor value of TDOA and by using Kalman filter to modify the measurement value of TDOA and AOA,most of the influence of NLOS propagation is eliminated,and the positioning accuracy is effectively improved.3.Based on the hardware platform of universal software radio peripheral and software platform of OpenBTS,this thesis designs the positioning experimental prototype by the idea of software radio.Through the experiment in the actual environment,the positioning of the GSM mobile phone is completed,and the positioning accuracy is improved compared with the existing GSM positioning. |
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