Visible Light Communication(VLC) Based Indoor Positioning Technique

At present,the global satellite positioning system(GPS)can perform well in outdoor environments.However,the complex indoor environment limits the utilization of satellite based positioning technology.As the requirement of location based services increases rapidly,the indoor location system without GPS satellite signal becomes a research hot.The visible light communication(VLC)based indoor positioning technique has many advantages,such as simple,flexible,low-cost and higher positioning performance.Therefore,in this paper,we study the VLC based indoor positioning technique and the content contains the following aspects:(1)Through analyzing the advantages and disadvantages of different indoor positioning techniques,the future application prospects of VLC indoor positioning system are discussed.Moreover,some existing VLC positioning techniques are introduced in details.And the characteristics of classical VLC positioning technology are obtained.(2)A VLC based orientation estimation algorithm is proposed for mobile device in indoor environments.The polar angle and azimuth angle measurements are first to be obtained from the existing image sensor and then to estimate the projection position of light emitting diodes(LEDs).By these project points,the orientation information can be estimated with the least square methods.The performed theoretical bound analyses are also obtained.Simulation results demonstrate that the proposed orientation estimation approach can considerably perform well under different scenarios.(3)A VLC based positioning algorithm is studied using the image matching technique.It includes the offline phase and the online phase.In the offline phase,the image fingerprint database for each grid is constructed.In the online phase,SIFT image matching algorithm is utilized to match the picture between real-time picture and fingerprint database.The chosen grid position by the matching process is the estimated target position.Simulation results demonstrate the positioning performance.(4)A VLC based positioning technique is proposed using the image matching technique and fingerprint database.In the offline phase,the image fingerprint database for each quadrant and the arrival-of-angle(AOA)and received signal strength indicator(RSSI)fingerprint database for each grid in the quadrant is constructed.In the online phase,through the coarse positionging and refine positioning processing,it can improve the positioning performance and real-time performance of the image matching technique based VLC positioning algorithm.