Research And Implementation Of Wireless Fingerprint Location Technology Based On WiFi

In recent years,various types of applications based on location services have greatly improved people's lives.Car navigation,bus line planning and other applications greatly facilitate people's travel outdoors.In such indoor environments as airports,hospitals,shopping malls and libraries,location services are extremely diversified.Applications based on location service have greatly changed people's lifestyles.In the outdoor environment,the traditional GPS positioning system can provide accurate positioning data.However,due to the floor covering and the complex indoor environment,traditional GPS positioning technology can not provide satisfying location performence indoors.With the development and popularization of WLAN technology,people gradually adopt WiFi indoor positioning system for indoor positioning.As a typical WiFi indoor positioning method,the wireless fingerprint location method has the characteristics of simple system development and low maintenance cost.Therefore,the wireless fingerprint location method has received a great deal of attention.This thesis aims to solve the problem of low precision and poor computing efficiency of the traditional wireless fingerprint location method.In the offline stage,thesis improves the effectiveness of fingerprint datasets through data preprocessing techniques.Specifically,the fingerprint data set is optimized by Kalman filtering of the sampling signal.On the other hand,using the historical signal strength information in the online positioning stage,an improved positioning method-time window assistant positioning method is proposed to increase the positioning accuracy and reduce the computational complexity.The use of records within the time window information to estimate the current location can avoid querying all the fingerprint data set each time.Compared with the traditional WKNN technology,the proposed algorithm can greatly improve the positioning accuracy and shorten the time required for positioning.After that,thesis designs a set of wireless indoor positioning system and gives all the module design and pseudocodes.Finally,the system's various modules were systematically tested.Experiments show that the proposed system basically meets the design requirements.