| Along with the increasing development of the "three S" technologies and modern cellular communications technologies, especially after America Federal Communications Commission(FCC) officially enacted the requirements of locating wireless Enhanced 911 callers, and appeared Location-Based Services(LBS) , the research of the mobile terminals location has been becoming a hotspot problem at home and abroad.In modern cellular communications systems, especially in city miscocell systems, because of the synthetical influences of several adverse factors, such as Non Line of Sight(NLOS) propagation, multipath propagation, hearability, multiple access interference and Geometric Dilution of Precision(GDOP), the performance of all existing positioning methods in cellular systems may be significantly degraded and the position estimation of the mobile terminals is inevitably influenced and biased; even when the error is severe, the position estimators may be broken down and be noneffective in positioning location. So, based on reviewing large numbers of related literatures and investigation, the author thoroughly analyzes the theories and principles of existing positioning methods, and summarizes that the common essential reason lies in the supposition of Line of Sight(LOS) propagation of radio waves, which doesn't resolve the environments influences, such as NLOS propagation, multipath propagation, hearability, multiple access interference and GDOP. In order to resolve these above problems theoretically, in this paper, for the first time, the author introduces the ray-tracing technology into the techniques of the mobile terminals in cellular communications systems. In order to match the ray-tracing technology, grid the observed areas in rapid, dynamic and grade, and improve the performance of positioning, the author first introduces the GIS technology, especially Voronoi diagrams, the technique with good characteristics and abroad applications, into the techniques of the mobile terminals in cellular communications systems. Therefore, the author putsHIforward a new method of positioning-the sequences of the electricfield intensity, time delay and angle of arrival positioning. The modeling calculation proves that the method is practical and feasible. The main works of the paper concentrate on the following:1) According to the location requests of LBS, in the paper, the current researching status of existing mobile terminals location in cellular systems at home and abroad are detailedly summarized, including fundamental location techniques and realization methods. The key technologies and difficult problems of the mobile terminals location in cellular systems, as well as the common factors and theories blemish are summarized.2) The ray-tracing technique is firstly introduced into the techniques of the mobile terminals location in cellular communications systems, resolving these problems in the methods existing in cellular communications systems from the view of the theory, and improving the precision, veracity and response rapidity and the whole location performance.3) The Voronoi diagrams is firstly introduced into the techniques of the mobile terminals location in cellular communications systems. It can grid the cellular areas in rapid, dynamic and grade, and can improve the whole performance of positioning more, be propitious to providing LBS information and improving service quality of LBS.4) The concept of the sequences of the electric field intensity, time delay and angle of arrival positioning is put forward. Based on theconcept, a new method of positioning-the sequences of the electricfield intensity, time delay and angle of arrival positioning is put forward. The meaning of the new method of positioning is perspicuity because of putting forward the concept. It makes clear that the positioning sequences contain the information of the electric field intensity, difference of time delay and angle of arrival. The modeling calculation proves that the new method of positi...
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