Research And Implementation Of Wi-Fi Indoor Location Method Based On Fingerprint

With the rapid development of mobile Internet and universal access to mobile smart devices,the demand of location-aware services increasing.Global navigation satellite systems and cellular mobile network systems basically meet the people's demand for outdoor positioning.However,positioning accuracy and positioning speed of global satellite navigation systems and cellular mobile network systems decreased significantly in the indoor environment,which can't meet the needs of the production and living.With the development of Wi-Fi(Wireless Fidelity)wireless technology and the covering of Wi-Fi network,indoor positioning based on Wi-Fi technology become possible.In all location-based technology based on Wi-Fi,the Wi-Fi location technology based on fingerprint is gaining in popularity,because it has high positioning accuracy and request low hardware condition.In this paper,for accuracy,speed and energy issues of the positioning I present the corresponding solutions by in-depth and systematic study,which have been validated the effectiveness and viability with comparing algorithms and experimental analysis.The main research work are as follows:1)By studying the Wi-Fi signal propagation characteristics,proposed an offline location fingerprint filtering methods based on Wi-Fi signal strength.Transformed the strongest signal in real time fingerprint into distance through the signal propagation,using the distance as the radius,the location of the AP with strongest signal as center,the fingerprint in the circle is effective.This method reduces the online position the stage number of fingerprint matching,increase the speed of the positioning of the system,reduce the energy consumption of positioning equipment.2)Analyzed using Euclidean distance as the objective function in calculating real-time location fingerprints and offline fingerprint of the defects in the distance,and put forward the improvement of the objective function.Improve the objective function to improve the position accuracy of fingerprint matching stage,offline location fingerprint matching to get closer to the backlog position coordinates,to improve the positioning precision of the positioning system.3)Doing positioning experiment and contrast experiment in actual Wi-Fi network environment,the experimental results show that the off-line location fingerprint filtering method based on signal strength can effectively decrease the number of matching for online positioning stage,improve system positioning speed and reduce energy consumption of equipment.Improvement of calculating the distance between the position fingerprint objective function than using Euclidean distance as the objective function positioning,better to improve the positioning precision of the system.4)Based on the theoretical basis above,design and implement a Wi-Fi indoor positioning system based on location fingerprinting and Android.