WLAN Heterogeneous Terminal Location Method Based On DBSCAN-GRNN-LSSVR Algorithm

With the continuous development of technology,people are increasingly demanding positioning,pay more and more attention to location-based services(LBS).The Global Positioning System(GPS)is a typical outdoor positioning system.GPS can provide precise positioning outdoors,but in the complicated indoor environment,Walls,roofs and other obstacles will affect the signal transmission,the positioning accuracy is not ideal.Because of its low cost,fast positioning speed,without additional hardware equipment,wide range of applications and other characteristics,WLAN positioning technology has received widespread attention.However,in practical applications,due to the problem of heterogeneous terminals(fingerprint database terminal and positioning terminal),in the WLAN indoor positioning system,the received signal strength(RSS)collected by the fingerprint terminal and the positioning terminal from each AP at the same point may be different,it will lead to excessive positioning deviation.Aiming at the excessive location error caused by heterogeneous terminal in WLAN indoor localization system,a solution based on DBSCAN-GRNN-LSSVR algorithm is proposed.In this thesis,the least square support vector regression(LSSVR)algorithm is employed to build the mapping relationship model between the RSS of fingerprint database terminal and physical coordinate locations.The scatter plot is obtained through listing the RSS values collected by the fingerprint database terminal and the test terminal at the calibration point.The boundary points and noise points are eliminated by density-based spatial clustering.Generalized regression neural network(GRNN)is used to construct the heterogeneous terminal mapping function of the RSS,Convert the positioning terminal RSS to fingerprint database terminal.The LSSVR model is used to determine the location of the target point.Proved by experiment,compared with LSSVR algorithm,using the proposed DBSCAN-GRNN-LSSVR algorithm to calibrate the heterogeneous terminal,test terminal positioning accuracy increased by 18-40%,which effectively solves the problem of excessive localization deviation caused by heterogeneous terminals.Then,in this thesis,we apply the DBSCAN-GRNN-LSSVR algorithm to the positioning of Dapu Science Park in Wuhu.Due to the large number of visitors,the accuracy of WLAN indoor positioning will be affected.In order to ensure the accuracy of positioning,we combine electronic tag localization system with fingerprinting based WLAN localization system to build a hybrid localization system.Proved by experiment,the hybrid positioning system can achieve more accurate positioning.