Gsm Mobile Position Information System Based On Special SMS

With the development of location services, China Mobile Communications Corporation (CMCC) and China Unicom have begun their LCS (location services) by CELL ID position technique, while disadvantages of it are still coming up more and more. The location accuracy cannot satisfy users. Other position techniques need add new measure unit in cellular network or the mobile station need to be modified. That is hard in China.Based on this background, this thesis proposes a location scheme based on special SMS (short message service). It makes use of original parameter in GSM network. Its location accuracy is better than CELL ID position technique. There is no modification needed on both network and mobile stations. When a GSM mobile station receives a special SMS, the mobile station will send some power measurement reports to the base station on uplink channel SACCH, and no one knows the above process. Then the measurement reports can be translated into the distance information and the mobile station's position will be estimated with designed special location algorithms.This paper also analyzes the PDU (Protocol Data Unit) format of SMS and realizes the special SMS.Then this paper analyzes the original location algorithms, and proposes a new CELL ID location algorithm which is combined with base station's information.A propagation model of radio wave, which is called corrected Hata propagation model educed from much real data in Hang Zhou, is proposed.Then this paper analyzes circle location algorithm and Fang location algorithm. This thesis also proposes distance sum-based outlier detection algorithm after many times position. The location tests result is listed and some relative problems are analyzed.At the end of this paper, the prototype of GSM mobile position information system based on special SMS has been designed and realized.