Wireless Indoor Positioning Method with Evaluation of Channel Propagation Model by TR-FMM

The positioning method based on time of flight (TOF) measurement, link the time delay to the position of the small mobile communications terminal to be located. Its accuracy depends on the suitability of the channel propagating model used for the actual wireless positioning system. In an indoor wireless network, the propagating condition is very difficult to predict due to indoor environment is variable, which comes from variant room layout or staff activities. In this paper, we present a novel method which dynamically estimates the propagating model based on an inverse evaluation procedure, using only received measurement TOF obtained by the fixed access points (APs) in real time. This method is a combination of simultaneous algebraic reconstruction technique and fast matching method (FMM). Once the optimized propagating model is estimated, it is possible to accurately determine the position of MS using our existing time reversal (TR) method, a positioning method employ transceivers interoperability principles for the MS and each AP. The proposed TR-FMM method is validated by simulations. These results show that it has great advantages in accuracy and complexity for indoor positioning system. The positioning deviation is about 3.2 cm based on the simulative analysis, and the accuracy of the positioning is improved 23.66 times with taking about 2 min comparing to the time reversal without the channel information.