An in-Depth Survey of Visible Light Communication Based Positioning Systems <s> Introduction <s> The Global Positioning System (GPS) is a satellite-based navigation and time transfer system developed by the U.S. Department of Defense. It serves marine, airborne, and terrestrial users, both military and civilian. Specifically, GPS includes the Standard Positioning Service (SPS) which provides civilian users with 100 meter accuracy, and it serves military users with the Precise Positioning Service (PPS) which provides 20-m accuracy. Both of these services are available worldwide with no requirement for a local reference station. In contrast, differential operation of GPS provides 2- to 10-m accuracy to users within 1000 km of a fixed GPS reference receiver. Finally, carrier phase comparisons can be used to provide centimeter accuracy to users within 10 km and potentially within 100 km of a reference receiver. This advanced tutorial will describe the GPS signals, the various measurements made by the GPS receivers, and estimate the achievable accuracies. It will not dwell on those aspects of GPS which are well known to those skilled in the radio communications art, such as spread-spectrum or code division multiple access. Rather, it will focus on topics which are more unique to radio navigation or GPS. These include code-carrier divergence, codeless tracking, carrier aiding, and narrow correlator spacing. <s> BIB001 </s> An in-Depth Survey of Visible Light Communication Based Positioning Systems <s> Introduction <s> To establish an underwater communication system for a swarm of submersibles, we developed an optical communication transceiver, small in size, combining the IrDA physical layer with 3 Watt high power light emitting diodes, emitting light in the green and blue part of the visible spectrum. This paper presents experimental results in air and under water. Furthermore, we show how this digital communication link can be used for accurate distance measurements without any modications. <s> BIB002 </s> An in-Depth Survey of Visible Light Communication Based Positioning Systems <s> Introduction <s> Though GPS is the most popular positioning system at present it does not perform well in indoor environments and metropolitan city areas. Wi-Fi positioning has received much attention due to its advantages with respect to indoor positioning and the wide spread of the Wi-Fi access points (APs). Its performance in an outdoor environment is also of interest as a Wi-Fi based positioning system can overcome the shortcomings of GPS. In this paper, the Wi-Fi positioning technologies which can be used in outdoor environments - trilateration and fingerprinting, are discussed. An experiment based on fingerprinting has been carried out in the Sydney CBD area where Wi-Fi APs are densely deployed. The test results show that the Wi-Fi positioning system based on fingerprinting works well for outdoor localization, especially when directional information is utilized. <s> BIB003 </s> An in-Depth Survey of Visible Light Communication Based Positioning Systems <s> Introduction <s> Visible light communication systems have gained prominence as a method for wireless underwater communications. This is because these systems are capable of long distance communications in water with high bandwidths. A requirement of visible light systems, however, is consistent line of sight to maintain a communication link. This arises from the directional nature of visible light emitters and detectors. One solution to this problem is to implement feedback control in order to “point” visible light emitters and detectors at one another. This in turn requires precise estimation of the relative locations of these two components as a feedback signal. In this work, a system is presented that uses the modulated light signal both as a medium with which to carry data and as a reference upon which to base the localization of a mobile robot. This is therefore a dual-use system, for both communication and localization. First, this paper presents the architecture of a dual-use visible light communication and localization system. The localization is carried out using an Extended Kalman Filter (EKF) algorithm. Then, a planar version of this dual-use system is tested, demonstrating the feasibility and effectiveness of the dual-use approach. <s> BIB004 </s> An in-Depth Survey of Visible Light Communication Based Positioning Systems <s> Introduction <s> With the invention of LED (Light Emitting Diode), the idea of using light as a communication medium has started again. VLC uses white Light Emitting Diodes (LED), which send data by flashing light at speeds undetectable to the human eye. One major advantage of VLC is that we can use the infrastructure around us without having to make any changes to it. LEDs' ability to transfer information signals over light ( light which is between 400THz to 800THz of frequency and whose wavelength is between 400nm to 700nm ) makes it a very good communication medium. Now the light we use in our daily life can not only be used for providing light but also for communication. Upon detailed investigation of VLC research, it was found that not a lot of research has been done to develop this technology for commercial use. But because research into VLC is relatively new, the possibilities are wide open. A lot of research is being done to make this technology available for commercial use in various fields, including Internet access and vehicle-to-road communication using traffic signal lights. From our review of the literature, it became evident that work should be done to look into the possibility of designing a new model that could fit the present infrastructure for indoor applications. Keywords—VLC (Visible Light Communication), LED (light emitting diode), OOK (On Off Keying), FSO (Free Space Optical). <s> BIB005 </s> An in-Depth Survey of Visible Light Communication Based Positioning Systems <s> Introduction <s> Indoor positioning based on visible light communication (VLC) technology has become a very popular research topic ::: recently. This paper provides an overview of different VLC based indoor positioning techniques and their performance. ::: Three schemes of location estimation together with their mechanisms are introduced. We then present a detailed ::: comparison on their performances in terms of accuracy, space dimension and complexity. We further discuss a couple of ::: factors that would affect the performance of each of these positioning systems, including multipath reflections and ::: synchronization. Finally, conclusions and future prospects of research are addressed. <s> BIB006 </s> An in-Depth Survey of Visible Light Communication Based Positioning Systems <s> Introduction <s> In this paper we introduce a novel localization algorithm based on visible light communications (VLC) and the trilateration technique. The new algorithm can be used for tracking people or machinery in an underground mining environment. The proposed method utilizes the concept of reference points in order to reduce the location estimation error. The proposed algorithm outperforms the LANDMARC (location identification based on dynamic active radio frequency identification (RFID) calibration) algorithm, which uses RFID tags to determine the location of an object, in terms of the location estimation error. <s> BIB007 </s> An in-Depth Survey of Visible Light Communication Based Positioning Systems <s> Introduction <s> The key techniques in indoor positioning based on visible light communication and the state of the art of this research were surveyed. First, the significance of indoor positioning based on visible light communication from two aspects of the limitations of current indoor positioning technology and the advantages of visible light communication was discussed; And then, the main four technology of indoor positioning based on visible light communication were summarized and the triangulation of RSS method and the principle of image positioning were introduced in detail; Next, the performance characteristics of various typical algorithms were compared and analyzed; In the end, several suggestions on future research of indoor positioning based on visible light communication were given. <s> BIB008 </s> An in-Depth Survey of Visible Light Communication Based Positioning Systems <s> Introduction <s> With the flourishing of wireless information access, indoor positioning is becoming a topic of interest in both academic and industry community. Numerous techniques have been proposed to address this problem under diverse circumstances. Recently, the area of indoor positioning is dominated by three kinds of methodologies, such as range-based positioning, fingerprint-based positioning and inertial positioning. This paper is presented to overview the indoor positioning techniques using visible light based on the range-based positioning. The state-of-the-art research results will be studied. The typical localization mechanisms used in visible light positioning systems are analyzed by evaluation metrics to provide an insight of the systems' performances. <s> BIB009 </s> An in-Depth Survey of Visible Light Communication Based Positioning Systems <s> Introduction <s> While visible light communication (VLC) with inherent advantages is believed to be the next generation of wireless technology, positioning using visible light also has the potential of becoming a standard approach for positioning in the future. Although many indoor positioning systems based VLC have been proposed recently, there is very few paper related outdoor positioning using visible light. In this paper, firstly we point out difficulties when using visible light for outdoor positioning. Then we survey existing indoor positioning techniques using visible light and evaluate the potentialities and challenges of applying them to outdoor positioning. <s> BIB010 </s> An in-Depth Survey of Visible Light Communication Based Positioning Systems <s> Introduction <s> Visible light LEDs, due to their numerous advantages, are expected to become the dominant indoor lighting technology. These lights can also be switched ON/OFF at high frequency, enabling their additional use for wireless communication and indoor positioning. In this article, visible LED light--based indoor positioning systems are surveyed and classified into two broad categories based on the receiver structure. The basic principle and architecture of each design category, along with various position computation algorithms, are discussed and compared. Finally, several new research, implementation, commercialization, and standardization challenges are identified and highlighted for this relatively novel and interesting indoor localization technology. <s> BIB011 </s> An in-Depth Survey of Visible Light Communication Based Positioning Systems <s> Introduction <s> This article presents a Light Intensity--based Positioning System (LIPS) for indoor environments. The system uses off-the-shelf light-emitting diode lamps as signal sources and light sensors as signal receivers. The design is inspired by the observation that a light sensor has deterministic sensitivity to both the distance and incident angle of a light signal, an under-utilized feature of photodiodes now widely found on mobile devices. We develop a stable and accurate light intensity model to capture the phenomenon, based on which a new positioning principle, Multi-Face Light Positioning, is established that uses three collocated sensors to uniquely determine the receiver’s position, assuming merely a single source of light. We have implemented a prototype on both dedicated embedded systems and smartphones. Experimental results show average positioning accuracy within 0.4m across different environments, with high stability against interferences from obstacles, ambient lights, temperature variation, and so on. <s> BIB012
In the field of positioning, the Global Positioning System (GPS) BIB001 is the best-known system. When it comes to coverage and cost, no other technologies can compete with it. That being said, GPS is far from a flawless positioning system. Apart from the widely-known disability of GPS in indoor environments, there are cases of GPS failures even in outdoor environments. Although GPS works very well in uncrowded areas, it poses many difficulties for use in metropolitan areas where tall buildings block the lines-of-sight of signal transmissions from satellites. In an experiment conducted in Sydney, only 30% of the test points received signals from a sufficient number of satellites (i.e., three) to calculate the position BIB003 . WiFi, Bluetooth, radio frequency identification (RFID), and camera-based positioning have been developed to complement GPS. Firstly, these techniques can provide indoor services. Secondly, even in outdoor circumstances these techniques are likely to give a higher accuracy, albeit at higher costs. In recent years, a new kind of technique has emerged, to become a very fruitful area of research on positioning. The technique mentioned here is visible light communication based positioning. VLC based positioning is a technique that uses visible light signals for determining the location of mobile devices and it has many advantages over RF based positioning. VLC based positioning systems can be installed inexpensively since they utilize existing lighting systems with very few modifications applied. Visible light positioning can be safely used in many places where RF cannot. For example, similar to VLC which can be used in hospital without causing any interference to MRI scanners BIB005 , VLC based positioning can be deployed in hospital. It can also be used in other RF-inappropriate environments such as underwater BIB002 BIB004 and in underground mines BIB007 . Another major advantage of VLC based positioning is that compared to RF, the visible light is less subject to multipath effects and thus make the propagation of visible light is more predictable BIB012  . Existing studies reveal that high accuracy can be achieved with VLC based positioning. Beside these advantages, the main motivation for the increasing amount of research on VLC based positioning is the prospect of LED devices and lighting systems becoming ubiquitous, setting the stage for VLC using LEDs in the near future. With many positive features such as cost-effectiveness, long life-time, ruggedness, environmentally friendliness, and greatly controllability, LEDs have been considered to be the lighting device for the 21st century. With the development of LEDs, VLC using LED light has also become the candidate for future wireless technology. It is believed that VLC is just the technique for enabling the Internet of Things (IoT). In the near future, VLC base stations, which also serve as lighting devices, might be installed everywhere, unfold the potential of utilizing them for a pervasive positioning system. Once LED lighting systems are installed everywhere, VLC based positioning can provide a seamless positioning service within much larger coverage than current techniques. In recent years, VLC based positioning has become an attractive topic and hundreds of papers in this field have been published. However, there are few survey works on VLC based positioning. In  , the concept of positioning based on VLC and its applications were introduced. However, the paper did not present any positioning algorithms or technical aspects of VLC based positioning. The authors of BIB006 classified and compared some VLC based positioning techniques. However, each technique was explained in very little detail. Also, the vision based positioning technique was not mentioned in the paper. In BIB008 , four positioning methods using VLC were presented and compared. The limitations of these methods were also pointed out. However, the paper did not mention Time of Arrival (TOA), Time Difference of Arrival (TDOA), and Angle of Arrival (AOA), which are among the most popular algorithms in the filed of VLC based positioning. In BIB009 an overview of the current status of VLC based indoor positioning systems is provided, with some additional papers being collected. However, very little detail on the positioning mechanisms was presented in that paper. A more detailed survey on VLC based positioning was given in BIB010 . However, that paper was focused on finding out the potentialities and challenges of using VLC for outdoor positioning so that a numerous papers related to indoor positioning using VLC were not taken into account. Also, some positioning algorithms such as proximity and fingerprinting was not mentioned in the paper. The authors in  provided quite an intensive survey on VLC based positioning techniques. However, there was a focus on the comparison between AOA and vision analysis algorithms. Therefore, other algorithms used in VLC based positioning were not surveyed deeply. And finally BIB011 provided an in-depth survey on VLC based positioning but there are still some algorithms such as proximity and TOA were not covered in the paper. In this paper, an in-depth survey on VLC based positioning systems is given. More than 100 papers, ranging from the pioneering papers to the current state-of-the-art, were collected and classified based on certain criteria. A detailed comparison among existing techniques is given. Current issues and research trends on VLC based positioning is also discussed.