Investigation Of Hybrid Location Based On GNSS And Wireless Location In Cellular Network

In cellular environments, because of the influence of several adverse factors, such as multipath, non-line-of-sight propagation, noise, interference and channel frequency characteristics, radio statistics measurements like TDOA, TOA and AOA related to mobile position, the performance of location algorithms may be significantly degraded and the position estimation of MS is inevitably biased. Therefore, in order to focus on the core problem of mobile location accuracy improvement, this thesis aims at TOA/TDOA location techniques and investigates the following cellular network based location techniques: reconstruction of TOA observations, a hybrid location algorithm based on data fusion, and error modeling method for a regional by Kriging interpolation. The main content includes:First of all, introduced the basic principles and the mathematical model equations of TOA/TDOA positioning method, and then described the main TOA/TDOA location algorithms in details. Meanwhile, the algorithm of GNSS positioning and evaluation of wireless location accuracy standards was explained.Secondly, making further research on the problem how to eliminate the effects of NLOS on TOA observations, and proposed two reconstruction algorithms for TOA value. By simulation under MATLAB soft, using the two proposed methods can improved the accuracy significantly.In addition, simulated GNSS positioning data and wireless location positioning data were calculated by a hybrid positioning method in NLOS environmental. This experimental results show that in most cases, hybrid location methods can improve the positioning accuracy effectively. The mode of data fusion was also discussed during the experiment. Because the mode had a significant effect on the positioning precision.Finally, considering all factors on wireless location, utilized the Kriging interpolation which is the basic tool of geo-statistics to generate the errors model of an area in real environment. As the model was completed, using it to correct the existing location results. The correcting results show that the proposed model had good effect on the mitigation of error. In order to verify the superiority of the algorithm of Kriging interpolation, other interpolation methods were also used for correcting calculation. The comparison between these modes released that the Kriging interpolation was better than any of other methods.