.toa / On Tdoa Non-direct Wave Localization Algorithm

Cellular wireless location technology has been a more and more active research area along with the the rapid development of mobile communication technology and the approaching of 3G age. A great deal of research results on the theory and application have appeared. Time of arrival and time difference of arrival (TOA/TDOA) based methods are two popular methods in wireless location. However, the non line of sight (NLOS) error is the major cause that degrades the location accuracy. How to suppress the NLOS error has been the key of improving the accuracy of wireless location, and also the focus of worldwide reasearchers.Line of sight (LOS) base station (BS) identification method is an effective way to minimize the effects of the NLOS contributions. It identifies and localizes with the LOS-BS. If the identification is correct, the accuracy is what the LOS localization algorithm can provide. This dissertation focuses on the research of LOS-BS identification based TOA/TDOA location algorithm under NLOS conditions and three aspect's works were done.1. The principle and algorithm of TOA based location method are been researched. We stress on the Chan's method and the approximate maximum likelihood localization (AML) algorithm. The algorithms are simulated and analyzed in the dissertation.2. A TOA based NLOS error suppressing method is been improved. The improved method is based on the AML estimation and the range residual test (RRT). The RRT method is simulated and compared with the present position residual test (PRT) method. The superiority of the proposed method is proved.3. A TDOA based NLOS error suppressing method is proposed, which is based on the range difference residual test (RDRT). It is the generalized method of RRT based TOA method. The proposed method is simulated and compared with the present NLOS suppressing method. The superiority of the proposed method is proved.