Research And Implementation Of Indoor Positioning Based On WiFi

With the rapid development of wireless communication and mobile intelligent terminal,there is a growing demand for indoor location-based service in business,medical,social,public safety and other areas.Compared with other positioning technology,wifi fingerprinting indoor localization has the advantages of high positioning accuracy,simple implementation,strong expansibility and low cost,therefore,this paper focuses on the fingerprinting localization technology and the main work can be summarized as follows:First of all,this thesis researches on the technical principle and matching algorithm of fingerprinting localization and analyzes its limitation in positioning efficiency and positioning accuracy.Traditional fingerprinting localization technology has a low positioning efficiency in the online phase,for this shortage,a LFDB classification algorithm based on multiple membership is proposed,which divides the reference points which has weak category feature into all possible categories,and thus reduces the risk of misclassification of reference points.Then,confirms the value of threshold by simulation to maximum the localization efficiency,in ensuring the localization accuracy of the premise.Secondly,A fingerprint localization algorithm based on directional AP(Access Point)weighting is proposed to further improve the positioning accuracy.The proposed algorithm weights AP according to the relevant coefficient between RSSI(Received Signal Strength Indication)and coordinate value in different regions and directions,then integrates the AP weights into the Euclidean distance of WKNN(Weighted K Nearest Neighbor)algorithm.Simulation results show that the proposed algorithm can effectively improve the positioning accuracy under different noise and density of reference points.Finally,based on the proposed algorithm,an indoor positioning system based on Android is designed and implemented.The system includes client and server,client mainly realizes the functions of user interaction,wifi scanning and data exchange,while server is mainly responsible for requests listening,database connection,algorithm execution and so on.In order to verify the performance of the system,a testing is implemented,and it's results are analyzed.