Optical Antenna Design For Visible Light Positioning System

Nowadays,location-based services(LBS)have a huge and rapidly growing market.Global positioning system(GPS)can satisfy the demand for LBS in outdoor environment,but it cannot be used in indoor scenario.In the past few decades,researchers proposed several methods for indoor positioning,such as indoor positioning methods based on Ultra-Wide-Band(UBW),Bluetooth,Wireless Local Area Networks(WLAN),and Visible Light Communication(VLC).Compared with other positioning methods,VLC-based positioning system can take advantage of the existing LED lighting infrastructure as the signal transmitter.So it has relative low cost on hardware.Moreover,VLC-based positioning system can achieve higher accuracy since it is not limited by electromagnetic interference.Thus,visible light positioning will be an important part of future indoor position systems,and used in various positioning applications.Our research focuses on the optical design in a received signal strength(RSS)based visible light positioning system.The main contents of this thesis are as follows:The first chapter reviewed the development of visible light positioning technology and the optical antenna design.In the second chapter,the key technologies of visible light positioning are introduced,including the modulation of light sources and the positioning algorithm.Then,the optical characteristics of the most commonly used RSS positioning system are introduced,i.e.,the characteristics of light sources,optical channel and detector.Finally,the principles and theory of an optical antenna design are introduced.The third chapter introduced the design of an optical antenna for LED transmitter in a visible light positioning system.We proposed the freeform lens based optical antennas for a VLC positioning system.By design theory of freeform lens,the optical antenna is designed with the targeted illumination distribution.Finally,the simulation proves that the designed free lens based optical antenna can improve the positioning accuracy of a VLC positioning system.The fourth chapter investigated the design of the receiver optical antenna in a visible light positioning system.The model of reflection channel in a RSS visible light positioning system is first discussed.Then,the influence of reflection channel on the illumination distribution and the positioning accuracy is analyzed.To mitigate the influence of the reflection,the receiver optical antenna is proposed by using multiple detectors to receive signals of different channels respectively.The simulation results showed that the designed receiver optical antenna can eliminate the effect of reflection signal and improve the positioning accuracy of a RSS positioning system.As a conclusion of this thesis,our work was summarized,and the future research on optical design in a VLC positioning system is prospected.