Research Of Positioning Algorithm Based On Cellular System

With the rapid development of mobile communication technology, especially the large-scale deployment of 3G wireless network, cellular wireless positioning has provided great convenience for people. This thesis mainly investigates the cellular positioning algorithm. The main work of it are as follows:1. The cellular wireless positioning technology is investigated. This thesis focuses on the investigation of traditional positioning methods and classical location algorithms, which include TOA location method, TDOA location method, AOA location method and Fang algorithm, Chan algorithm, Taylor algorithm, Friedlander algorithm, compares their performance by simulation, and analyzes factors of affecting location accuracy .2. In order to resolve the problem of NLOS propogation in cellular network, the Chan algorithm of static positioning is improved. Based on the COST259 model, the algorithm is aimed at selecting the best measurements from all of the measuring combinations by residual sorting and changing the weight coefficient with modifying the covariance matrix in Chan algorithm, the integration of the above two measures can restrain the NLOS error effectively. The simulation results show that the amended algorithm can improve the location accuracy and efficiency in the condition of NLOS propagation to some extent.3. The kalman algorithm of dynamic positioning is improved. Based on kalman filter and Greenstein model, the algorithm identifies NLOS error by judgment and mitigates it with its mean modifying new information directly, thus the TOA measurements are reconstructed; then modifies the measuring matrix and gets the locating results using the reconstructed measurements. The simulation results show that the proposed method can mitigate NLOS error effectively and improve the location accuracy.