【作者】 吴楠；

【导师】 杨爱英；

【作者基本信息】 北京理工大学 ， 电子科学与技术， 2017， 硕士

【摘要】 随着社会的发展,人们对于基于位置的服务(Location Based Service,LBS)的需求逐渐增长,室内定位服务有着巨大应用前景和广阔的市场。全球定位系统可以满足户外环境下LBS的需求,但在室内场景中则不能使用。在过去的几十年中,研究人员提出了多种室内定位方法,例如基于超宽带,蓝牙,无线局域网和可见光通信的室内定位技术。与其他定位方法相比,基于可见光通信的定位系统可以利用现有的LED照明设施作为信号发射源,所以硬件成本相对较低。而且,由于可见光波段不受电磁干扰的限制,基于可见光通信的定位系统可以达到更高的精度。因此,可见光定位将成为未来室内定位系统的重要组成部分,并且有着广阔的应用前景。本文针对可见光定位技术进行了调研和研究,着重研究了基于接收信号强度(Received Signal Strength,RSS)的可见光定位系统中的光学天线设计问题。本文研究的主要内容包括:第一章绪论部分介绍了本文的研究背景和研究意义;随后介绍了国内外对于可见光定位技术和光学天线设计的研究进展;最后基于目前国内外的研究现状提出了本文的研究内容。第二章介绍了本文研究的理论基础。首先介绍了可见光定位的相关技术,包括光源调制技术与相关算法。接着介绍了RSS定位系统的光学特性,包括光源、信道和探测器的特性。最后介绍了光学天线设计需要遵循的原理和相关技术。第三章介绍了本文设计的可见光定位系统的发射天线。首先讨论了光学天线设计时所采用的自由曲面设计方法。接下来对所设计的光学天线进行照明仿真,观察分析光学天线对LED光能分布的优化效果。最后将所设计的光学天线应用到RSS可见光定位系统中,通过仿真证明了光学发射天线对可见光定位系统定位精度的提升。第四章介绍了本文设计的可见光定位系统的接收天线。首先讨论了RSS可见光定位系统反射信道的模型。接下来通过仿真分析了反射信道对于光照度分布以及定位精度的影响。针对反射信道对定位精度的影响,我们提出了一种多探测器组合的接收天线设计方案:使用不同接收视场角的多个探测器分别接收不同信道的信号,估计并消除反射信号的影响。仿真结果证明了所设计的接收天线可以消除反射信号对探测器接收信号的干扰和对定位精度的影响。最后对全文的研究进行总结,提出未来可见光定位系统中的光学设计的发展方向。更多还原

【Abstract】 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.更多还原