Research On Angle/Distance Joint Localization Algorithm With Single Station Using WLAN Channel State Information

The development of information technology and the increasing demand of location service make the indoor positioning technology become a hot spot in the research at home and abroad.Most current indoor positioning solutions find that WLAN(Wireless Local Area Network)based positioning technology is the most widely used,however,most of the WLAN based positioning technologies need to be located in conjunction with multiple Wi-Fi Access Points(APs),the positioning accuracy is lower or even unable to locate with single one AP.Aiming at the single AP positioning ubiquitous in the indoor environment,this thesis focuses on angle/distance joint localization algorithm with single station using WLAN channel state information.The main contents of this thesis are as follows:First of all,this thesis studies how to utilize the Orthogonal Frequency Division Multiplexing(OFDM)technology combined with multi-carrier channel state information virtual large-scale antenna array in WLAN system to solve the problem of low accuracy of angle measurement accuracy due to the number of array elements in the indoor environment.This thesis studies the super-resolution AOA estimation algorithm,and uses the spatial smoothing MUSIC algorithm to jointly estimate the Angle of Arrival(AOA)and Time of Arrival(TOA)signals to improve the resolution of angle estimation.This thesis studies the direct path discrimination algorithm based on clustering,and uses the affine propagation clustering algorithm to cluster the two dimensional information of AOA and TOA.The weight distribution algorithm is used to identify the direct path.Then,this thesis analyzes in detail the influence of the phase error introduced in the existing commercial Wi-Fi equipment on the TOA estimation,and proposes an adaptive signal propagation model under the premise of the error can not be completely eliminated,and using the CSI amplitude information to estimate the distance,this method can reduce the influence of phase error and improve the accuracy of distance estimation.This thesis also analyzes the spatial characteristics of Line-of-Sight(LOS)and Non-Line-of Sight(NLOS)paths,and proposed a LOS/NLOS environment recognition algorithm based on the algorithm of direct path discrimination.The super-resolution angle and the high-precision distance information is used for single station positioning in the LOS environment,in the NLOS environment,no positioning is performed,the position stays in the last LOS environment positioning point.When the current environment is determined to be a LOS environment,the positioning is continued using the single AP positioning algorithm of the LOS environment.Finally,the algorithm is tested and verified,and a test verification platform is built,the experimental results show that the single station positioning system designed in this thesis can achieve the AOA estimation accuracy of 7 degrees with 67% confidence,and distance error of 1.3 meters with 67% confidence,and localization accuracy of 1.8 meters with 67% confidence.Therefore,the algorithm can use the existing three-antenna AP to meet indoor single station positioning needs.