The precise underground localization method based on WIFI network

The localization information of the mobile nodes is captured by the nodes of the underground WIFI network collaboratively through the received RF amplitudes. This method is based on the information fusion of Markov chain. The spectrum distribution information between two adjacent nodes is perceived by the mobile node, and then the frequency and power vector are sent to the fusion center (FC) to estimate the location coordinate. Combining underground characteristics with the Markov process, the incremental maximum a posteriori (MAP) estimation algorithm is employed to make locauzation judgment and obtain the relationship between mobile node and electronic map coordinates. The simulation result shows that the method used in the coal mine wireless localization system can improve the localization accuracy to 1.6 meters.