Research On Positioning Technology In Cdma2000-1x Positioning System

In order to obtain high-accuracy positioning results using single position measuring equipment in cdma2000-lx positioning system and in view of the characteristics of positioning system, the positioning scheme is proposed to eliminate the affect of error and makes the accuracy of positioning results improved to a certain extent in this paper.First, through researching on some common positioning methods and considering the requirements of positioning system, the conclusion that the TOA and AOA hybrid method is the more suitable for the position system is proposed.Then, the positioning scheme is proposed in base on the TOA and AOA hybrid method, and then some methods are proposed to obtain positioning parameters.An Improved Genetical Algorithm has been proposed through combining the idea of N-order polynomial smoothing and then weighted amendment with Genetical Algorithm. It has been used to eliminate the influence of Non-line -of sight error and multi-path propagation error on the Carrier-to-Interference Ratio. Using this method not only can affectively avoid the phenomenon of premature in Genetic Algorithm, but also can flexibly change the searching precision of Algorithms according to the fact situations, thus the orientation of arrival signal can be estimated accurately. Through the test of field experiments and Matlab simulation experiments, fairly good results could be achieved by using this method.Then the Combined Kalman Method is proposed through combining the Measurements Discarding Method with Overall Shifting Method by setting a standard deviation threshold to eliminate the influences of error. It not only eliminates the influences of lesser error on measurements, but also eliminates the influences of the biggish error of measurements on follow-up estimates and effectively depresses the available coefficient limitation caused by non-astringency of Kalman Filter in Overall Shifting Method, which further reduces the available coefficient, more eliminates the non-line of sight error, and improves the positioning accuracy. Through the test of field experiments and Matlab simulation experiments, fairly good results could be achieved by using this method.Finally, the positioning scheme is actualized through Matlab simulation experiments and the precision of positioning results is analyzed based on the data of field test. The positioning accuracy is improved to a certain extent and fairly good results could be achieved by using these optimization algorithms.