A State-of-the-Art Survey on Multidimensional Scaling-Based Localization Techniques <s> B. Local Positioning Systems <s> A novel system for the location of people in an office environment is described. Members of staff wear badges that transmit signals providing information about their location to a centralized location service, through a network of sensors. The paper also examines alternative location techniques, system design issues and applications, particularly relating to telephone call routing. Location systems raise concerns about the privacy of an individual and these issues are also addressed. <s> BIB001 </s> A State-of-the-Art Survey on Multidimensional Scaling-Based Localization Techniques <s> B. Local Positioning Systems <s> Instrumenting the physical world through large networks of wireless sensor nodes, particularly for applications like environmental monitoring of water and soil, requires that these nodes be very small, lightweight, untethered, and unobtrusive. The problem of localization, that is, determining where a given node is physically located in a network, is a challenging one, and yet extremely crucial for many of these applications. Practical considerations such as the small size, form factor, cost and power constraints of nodes preclude the reliance on GPS of all nodes in these networks. We review localization techniques and evaluate the effectiveness of a very simple connectivity metric method for localization in outdoor environments that makes use of the inherent RF communications capabilities of these devices. A fixed number of reference points in the network with overlapping regions of coverage transmit periodic beacon signals. Nodes use a simple connectivity metric, which is more robust to environmental vagaries, to infer proximity to a given subset of these reference points. Nodes localize themselves to the centroid of their proximate reference points. The accuracy of localization is then dependent on the separation distance between two-adjacent reference points and the transmission range of these reference points. Initial experimental results show that the accuracy for 90 percent of our data points is within one-third of the separation distance. However, future work is needed to extend the technique to more cluttered environments. <s> BIB002 </s> A State-of-the-Art Survey on Multidimensional Scaling-Based Localization Techniques <s> B. Local Positioning Systems <s> The proliferation of mobile computing devices and local-area wireless networks has fostered a growing interest in location-aware systems and services. In this paper we present RADAR, a radio-frequency (RF)-based system for locating and tracking users inside buildings. RADAR operates by recording and processing signal strength information at multiple base stations positioned to provide overlapping coverage in the area of interest. It combines empirical measurements with signal propagation modeling to determine user location and thereby enable location-aware services and applications. We present experimental results that demonstrate the ability of RADAR to estimate user location with a high degree of accuracy. <s> BIB003 </s> A State-of-the-Art Survey on Multidimensional Scaling-Based Localization Techniques <s> B. Local Positioning Systems <s> This paper presents the design, implementation, and evaluation of Cricket , a location-support system for in-building, mobile, location-dependent applications. It allows applications running on mobile and static nodes to learn their physical location by using listeners that hear and analyze information from beacons spread throughout the building. Cricket is the result of several design goals, including user privacy, decentralized administration, network heterogeneity, and low cost. Rather than explicitly tracking user location, Cricket helps devices learn where they are and lets them decide whom to advertise this information to; it does not rely on any centralized management or control and there is no explicit coordination between beacons; it provides information to devices regardless of their type of network connectivity; and each Cricket device is made from off-the-shelf components and costs less than U.S. $10. We describe the randomized algorithm used by beacons to transmit information, the use of concurrent radio and ultrasonic signals to infer distance, the listener inference algorithms to overcome multipath and interference, and practical beacon configuration and positioning techniques that improve accuracy. Our experience with Cricket shows that several location-dependent applications such as in-building active maps and device control can be developed with little effort or manual configuration. <s> BIB004 </s> A State-of-the-Art Survey on Multidimensional Scaling-Based Localization Techniques <s> B. Local Positioning Systems <s> This paper faces the problem of configuration and communication in a distributed radio sensor network composed of identical sensors randomly placed in a 2 or 3 dimensional space. The reference is provided by objects with known position called masters. Two architectures are shown, the first uses one master, the second three masters. The one master architecture makes it possible to identify and locate all the sensors in space and to calculate for each of them the lowest energy transmission path to reach the master. The three master architecture locates each sensor when a transmission of information occurs by triangulation and can not optimize energy consumption during sensor communication. On the other hand, it is able to localize also moving sensors or to handle dynamically changing sensor topologies. The results show that the three master architecture is faster, but it implies an energy waste of 26 times greater than the one master architecture. <s> BIB005 </s> A State-of-the-Art Survey on Multidimensional Scaling-Based Localization Techniques <s> B. Local Positioning Systems <s> Determining physical location of indoor objects is one of the key issues in development of context-aware applications in ubiquitous computing environments. This is mainly because context information obtained from sensor networks is meaningful only when the physical location of the context information source is determined. Recently, several indoor location information systems, such as Active Bat and Cricket, have been developed for precise indoor object localization. However, to provide accurate physical location tracking in large-scale space, those systems requires a lot of manual configuration for all the ultrasonic sensor nodes. To reduce configuration costs, we developed a new indoor positioning system called DOLPHIN. The DOLPHIN system consists of distributed wireless sensor nodes which are capable of sending and receiving RF and ultrasonic signals. These nodes are attached to various indoor objects. And using a novel distributed positioning algorithm in the nodes, DOLPHIN enables autonomous positioning of the objects with minimal manual configuration. This paper describes the design and implementation of the DOLPHIN system, and evaluates basic performance through several experiments in an indoor environment. <s> BIB006 </s> A State-of-the-Art Survey on Multidimensional Scaling-Based Localization Techniques <s> B. Local Positioning Systems <s> This paper describes IRIS-LPS (InfraRed Indoor Scout), an optical infrared local positioning system. The tracked objects carry active tags that emit infrared signals which are received by a stationary mounted stereo-camera. The system is based on cheap off-the-shelf components, is easy to deploy, and features a large range of coverage. It is capable of tracking a large number of tags without significant performance impact, since the sampling rate remains constant with an increasing number of tags. A test installation of the system has been evaluated in a lecture hall. The positioning system is utilized by our audio-centric user terminal called Talking Assistant. This and other application scenarios are described at the end. <s> BIB007 </s> A State-of-the-Art Survey on Multidimensional Scaling-Based Localization Techniques <s> B. Local Positioning Systems <s> In Korea, telematics is regarded as the technology to enhance and make everyday-driving experience more comfortable and safer. An essential part of the telematics is navigation and it is mainly based on GPS as the choice of positioning technology. The accuracy of GPS, however, is approximately ten to twenty meters. Combining with map-matching technologies, most navigation systems guide drivers with a best effort manner. In addition to telematics, RFID (Radio Frequency Identification) is an old but newly emerged technology. In this paper, we incorporate RFID technology into a navigation system to improve the accuracy. The skeleton of the idea is as follows: install RFID tags on roads in a certain way, store very accurate location information along with other necessary information in the tags, add an RFID reader module to the navigation system, and use this new location information along with GPS and a gyroscope to produce highly accurate location information. With this scheme, the accuracy of positioning can be dramatically improved, especially in tunnels and in downtown areas. Preliminary results show that this idea is feasible. <s> BIB008 </s> A State-of-the-Art Survey on Multidimensional Scaling-Based Localization Techniques <s> B. Local Positioning Systems <s> Location systems have long been identified as an important component of emerging mobile applications. Most research on location systems has focused on precise location in indoor environments. However, many location applications (for example, location-aware web search) become interesting only when the underlying location system is available ubiquitously and is not limited to a single office environment. Unfortunately, the installation and calibration overhead involved for most of the existing research systems is too prohibitive to imagine deploying them across, say, an entire city. In this work, we evaluate the feasibility of building a wide-area 802.11 Wi-Fi-based positioning system. We compare a suite of wireless-radio-based positioning algorithms to understand how they can be adapted for such ubiquitous deployment with minimal calibration. In particular, we study the impact of this limited calibration on the accuracy of the positioning algorithms. Our experiments show that we can estimate a user's position with a median positioning error of 13-40 meters (depending upon the characteristics of the environment). Although this accuracy is lower than existing positioning systems, it requires substantially lower calibration overhead and provides easy deployment and coverage across large metropolitan areas. <s> BIB009 </s> A State-of-the-Art Survey on Multidimensional Scaling-Based Localization Techniques <s> B. Local Positioning Systems <s> This paper actualizes the classification of location management methods published up to now and presents results of a related extensive performance comparison of the most important paradigms for location management in cellular networks. First, a universal structure of a performance analysis framework for location management methods is defined and analyzed. Then, both a user mobility model and a specific simulation environment claiming to be as realistic as possible are suggested and implemented. Finally, the simulation framework obtained is used for a systematic comparative performance analysis of a representative sample of the most important location management schemes. The overall conclusion is that a location-area based location management method designed around a profile or history-based direction information offers the absolute best performance, in terms of location management cost, compared to all other alternative approaches. The key difference from previous works in literature is clearly underlined concerning both mobility modeling and novel location management schemes. <s> BIB010 </s> A State-of-the-Art Survey on Multidimensional Scaling-Based Localization Techniques <s> B. Local Positioning Systems <s> Several motion analysis systems are used by researchers to quantify human motion and to perform accurate surgical procedures. The Optotrak 3020 is one of these systems and despite its widespread use there is not any published information on its precision and repeatability. We used a repeated measures design study to evaluate the precision and repeatability of the Optotrak 3020 by measuring distance and angle in three sessions, four distances and three conditions (motion, static vertical, and static tilted). Precision and repeatability were found to be excellent for both angle and distance although they decreased with increasing distance from the sensors and with tilt from the plane of the sensors. Motion did not have a significant effect on the precision of the measurements. In conclusion, the measurement error of the Optotrak is minimal. Further studies are needed to evaluate its precision and repeatability under human motion conditions. <s> BIB011 </s> A State-of-the-Art Survey on Multidimensional Scaling-Based Localization Techniques <s> B. Local Positioning Systems <s> Wireless indoor positioning systems have become very popular in recent years. These systems have been successfully used in many applications such as asset tracking and inventory management. This paper provides an overview of the existing wireless indoor positioning solutions and attempts to classify different techniques and systems. Three typical location estimation schemes of triangulation, scene analysis, and proximity are analyzed. We also discuss location fingerprinting in detail since it is used in most current system or solutions. We then examine a set of properties by which location systems are evaluated, and apply this evaluation method to survey a number of existing systems. Comprehensive performance comparisons including accuracy, precision, complexity, scalability, robustness, and cost are presented. <s> BIB012 </s> A State-of-the-Art Survey on Multidimensional Scaling-Based Localization Techniques <s> B. Local Positioning Systems <s> Installing indoor location system prototypes yields practical lessons about how to design and deploy future ubiquitous technologies. The design of context-aware technologies has been on many research team agendas since Mark Weiser first described his ubiquitous computing vision. Determining the location of people and objects in indoor environments with a high degree of accuracy is a main technical obstacle to achieving this vision. <s> BIB013 </s> A State-of-the-Art Survey on Multidimensional Scaling-Based Localization Techniques <s> B. Local Positioning Systems <s> The term “location fingerprinting” covers a wide variety of methods for determining receiver position using databases of radio signal strength measurements from different sources. In this work we present a survey of location fingerprinting methods, including deterministic and probabilistic methods for static estimation, as well as filtering methods based on Bayesian filter and Kalman filter. We present a unified mathematical formulation of radio map database and location estimation, point out the equivalence of some methods from the literature, and present some new variants. A set of tests in an indoor positioning scenario using WLAN signal strengths is performed to determine the influence of different calibration and location method parameters. In the tests, the probabilistic method with the kernel function approximation of signal strength histograms was the best static positioning method. Moreover, all filters improved the results significantly over the static methods. <s> BIB014 </s> A State-of-the-Art Survey on Multidimensional Scaling-Based Localization Techniques <s> B. Local Positioning Systems <s> Wi-Fi ingerprint-based localization is currently the most promising approach to building metropolitan-scale localization systems for both indoor and outdoor environments. A Wi-Fi fingerprint localization system makes use of a radio map that contains Wi-Fi signals received at various locations, and uses the map for location estimation. Thus, the accuracy of a Wi-Fi fingerprint localization system greatly depends on the quality of its radio map. This paper explores various properties of a metropolitan radio map that may affect the accuracy of Wi-Fi fingerprint localization systems. In this study, metropolitan-scale radio maps are obtained using war walking and war driving. These maps contain hundreds of thousands of access points and signal samples. A detailed comparison analysis of selected radio map properties reveals how different map properties affect the difference between the positional accuracies of the driving and walking radio maps in Wi-Fi fingerprint-based localization. <s> BIB015 </s> A State-of-the-Art Survey on Multidimensional Scaling-Based Localization Techniques <s> B. Local Positioning Systems <s> This paper looks at the scalability problems inherent in the Active Bat system: an outside-in ultrasonic location system. Such systems are typically associated with higher positioning accuracies and longer tag battery lifetimes relative to comparable inside-out systems. However, they are often criticised for a lack of scalability since multiple tags must be addressed in series to prevent interference within the positioning medium. Multiple radio zones have previously been used to address this problem. We show that this approach is sub-optimal both in terms of system complexity and in terms of the location update rates that can be achieved. We propose a general solution to the scalability problem based on the computation of dynamic bounding regions within which corresponding tags are almost certainly located. These regions are used to determine when tags are sufficiently well separated to be queried concurrently without the risk of interference. We test this approach using real data, concluding that bounding regions permit more concurrency than is possible using multiple radio zones whilst at the same time reducing the complexity of the system. <s> BIB016 </s> A State-of-the-Art Survey on Multidimensional Scaling-Based Localization Techniques <s> B. Local Positioning Systems <s> This chapter contains sections titled: Introduction Basic Methods Used in Positioning Systems Overview of Positioning Systems Comparison of Basic Methods and Positioning Systems Conclusion, Summary, and Future Applications References <s> BIB017 </s> A State-of-the-Art Survey on Multidimensional Scaling-Based Localization Techniques <s> B. Local Positioning Systems <s> The widespread adoption of the Wireless Sensor Networks (WSNs) in various applications in the terrestrial environment and the rapid advancement of the WSN technology have motivated the development of Underwater Acoustic Sensor Networks (UASNs). UASNs and terrestrial WSNs have several common properties while there are several challenges particular to UASNs that are mostly due to acoustic communications, and inherent mobility. These challenges call for novel architectures and protocols to ensure successful operation of the UASN. Localization is one of the fundamental tasks for UASNs which is required for data tagging, node tracking, target detection, and it can be used for improving the performance of medium access and network protocols. Recently, various UASN architectures and a large number of localization techniques have been proposed. In this paper, we present a comprehensive survey of these architectures and localization methods. To familiarize the reader with the UASNs and localization concepts, we start our paper by providing background information on localization, state-of-the-art oceanographic systems, and the challenges of underwater communications. We then present our detailed survey, followed by a discussion on the performance of the localization techniques and open research issues. <s> BIB018 </s> A State-of-the-Art Survey on Multidimensional Scaling-Based Localization Techniques <s> B. Local Positioning Systems <s> Ultrasound positioning systems for indoor use can be distinguished by what kind of information they extract from the received signal. Time-of-flight (TOF) is measured with reference to a radio signal to get ultrasound time-of- arrival (TOA). Line-of-sight to three or more nodes is required for 3D positioning. Accuracy is in the cm or sub-cm range. A radio-free alternative can be made if time-difference-of-arrival (TDOA) is measured instead. Coding of the pulse is often used in order to allow simultaneous transmission from multiple transmitters. The simplest received signal strength (RSS) systems are binary and will just determine if the ultrasound signal can be detected or not. This is used on its own for room-level positioning. Another important application is in assisting RSS-based RF-systems such as WLAN positioning. The ultrasound RSS-system helps reduce the number of large errors (5–10 m) of the WLAN-system. Such systems have recently been deployed world-wide today by companies like Sonitor and Aeroscout. It has also just been demonstrated that RSS-based ultrasound positioning can be done with accuracies in the 10 cm range. This parallels the ubiquitous RF-based RSS systems and requires a propagation model. For ultrasound the model involves spherical spreading and absorption. There are also hybrid systems where the entire echo structure in the time history of the received signal is analyzed. Both the amplitude and time information are used in order to obtain a position of the node using only a single transmitter. <s> BIB019 </s> A State-of-the-Art Survey on Multidimensional Scaling-Based Localization Techniques <s> B. Local Positioning Systems <s> Abstract Indoor positioning has emerged as a hot topic that gained gradual interest from both academia and industry. Accurate estimation is necessitated in a variety of location-based services such as healthcare, repository tracking, and security. Additional equipment for location sensing could be used for accurate estimation, but they are not widely used in general because those alternatives will cause specialization in brands and will be costly. Among all suggestions in literature including hardware and intense sophisticated computations, a versatile and low-cost location determination technology, which uses existing WLAN infrastructure of indoor environments, has been developed without incurring extra charge; this method is rising as a way of positioning. WLAN is capable to be used within an indoor positioning system soon in real environments. It is a good alternative in terms of accuracy, precision and cost, compared to similar systems. Especially with the common usage of smartphones and tablet PCs, it became the most easy- to-use method, too. In this paper, we present a brief survey on such systems, methodologies, techniques and discuss advantages and disadvantages of each of these. <s> BIB020 </s> A State-of-the-Art Survey on Multidimensional Scaling-Based Localization Techniques <s> B. Local Positioning Systems <s> We explore the indoor positioning problem with unmodified smartphones and slightly-modified commercial LED luminaires. The luminaires-modified to allow rapid, on-off keying-transmit their identifiers and/or locations encoded in human-imperceptible optical pulses. A camera-equipped smartphone, using just a single image frame capture, can detect the presence of the luminaires in the image, decode their transmitted identifiers and/or locations, and determine the smartphone's location and orientation relative to the luminaires. Continuous image capture and processing enables continuous position updates. The key insights underlying this work are (i) the driver circuits of emerging LED lighting systems can be easily modified to transmit data through on-off keying; (ii) the rolling shutter effect of CMOS imagers can be leveraged to receive many bits of data encoded in the optical transmissions with just a single frame capture, (iii) a camera is intrinsically an angle-of-arrival sensor, so the projection of multiple nearby light sources with known positions onto a camera's image plane can be framed as an instance of a sufficiently-constrained angle-of-arrival localization problem, and (iv) this problem can be solved with optimization techniques. We explore the feasibility of the design through an analytical model, demonstrate the viability of the design through a prototype system, discuss the challenges to a practical deployment including usability and scalability, and demonstrate decimeter-level accuracy in both carefully controlled and more realistic human mobility scenarios. <s> BIB021 </s> A State-of-the-Art Survey on Multidimensional Scaling-Based Localization Techniques <s> B. Local Positioning Systems <s> Exploiting the increasingly wide use of Light-emitting Diode (LED) lighting, in this paper, we study the problem of using visible LED lights for accurate localization. The basic idea is to leverage the existing lighting infrastructure and apply trilateration to localize any devices with light sensing capability (e.g., a smartphone), using LED lamps as anchors. Through the design of Epsilon, we identify and tackle several technique challenges. In particular, we establish and experimentally verify the optical channel model for localization. We adopt BFSK and channel hopping to enable reliable location beaconing from multiple, uncoordinated light sources over the shared optical medium. We handle realistic situations towards robust localization, for example, we exploit user involvement to resolve the ambiguity in case of insufficient LED anchors. We have implemented the Epsilon system and evaluated it with a small scale hardware testbed as well as moderate-size simulations. Experimental results confirmed the effectiveness of Epsilon: the 90th percentile accuracies are 0.4m, 0.7m and 0.8m for three typical office environments. Even in the extreme situation with a single light, the 90th percentile accuracy is 1.1m. We believe that visible light based localization is promising to significantly improve the positioning accuracy, despite few open problems in practice. <s> BIB022 </s> A State-of-the-Art Survey on Multidimensional Scaling-Based Localization Techniques <s> B. Local Positioning Systems <s> This article considers the joint problem of packet scheduling and self-localization in an underwater acoustic sensor network with randomly distributed nodes. In terms of packet scheduling, our goal is to minimize the localization time, and to do so we consider two packet transmission schemes, namely a collision-free scheme (CFS), and a collision-tolerant scheme (CTS). The required localization time is formulated for these schemes, and through analytical results and numerical examples their performances are shown to be dependent on the circumstances. When the packet duration is short (as is the case for a localization packet), the operating area is large (above 3 km in at least one dimension), and the average probability of packet-loss is not close to zero, the collision-tolerant scheme is found to require a shorter localization time. At the same time, its implementation complexity is lower than that of the collision-free scheme, because in CTS, the anchors work independently. CTS consumes slightly more energy to make up for packet collisions, but it is shown to provide a better localization accuracy. An iterative Gauss-Newton algorithm is employed by each sensor node for self-localization, and the Cramer Rao lower bound is evaluated as a benchmark. <s> BIB023 </s> A State-of-the-Art Survey on Multidimensional Scaling-Based Localization Techniques <s> B. Local Positioning Systems <s> The proliferation of Bluetooth Low-Energy (BLE) chipsets on mobile devices has lead to a wide variety of user-installable tags and beacons designed for location-aware applications. In this paper, we present the Acoustic Location Processing System (ALPS), a platform that augments BLE transmitters with ultrasound in a manner that improves ranging accuracy and can help users configure indoor localization systems with minimal effort. A user places three or more beacons in an environment and then walks through a calibration sequence with their mobile device where they touch key points in the environment like the floor and the corners of the room. This process automatically computes the room geometry as well as the precise beacon locations without needing auxiliary measurements. Once configured, the system can track a user's location referenced to a map. The platform consists of time-synchronized ultrasonic transmitters that utilize the bandwidth just above the human hearing limit, where mobile devices are still sensitive and can detect ranging signals. To aid in the mapping process, the beacons perform inter-beacon ranging during setup. Each beacon includes a BLE radio that can identify and trigger the ultrasonic signals. By using differences in propagation characteristics between ultrasound and radio, the system can classify if beacons are within Line-Of-Sight (LOS) to the mobile phone. In cases where beacons are blocked, we show how the phone's inertial measurement sensors can be used to supplement localization data. We experimentally evaluate that our system can estimate three-dimensional beacon location with a Euclidean distance error of 16.1cm, and can generate maps with room measurements with a two-dimensional Euclidean distance error of 19.8cm. When tested in six different environments, we saw that the system can identify Non-Line-Of-Sight (NLOS) signals with over 80% accuracy and track a user's location to within less than 100cm. <s> BIB024 </s> A State-of-the-Art Survey on Multidimensional Scaling-Based Localization Techniques <s> B. Local Positioning Systems <s> Visible Light Positioning (VLP) provides a promising means to achieve indoor localization with sub-meter accuracy. We observe that the Visible Light Communication (VLC) methods in existing VLP systems rely on intensity-based modulation, and thus they require a high pulse rate to prevent flickering. However, the high pulse rate adds an unnecessary and heavy burden to receiving devices. To eliminate this burden, we propose the polarization-based modulation, which is flicker-free, to enable a low pulse rate VLC. In this way, we make VLP light-weight enough even for resource-constrained wearable devices, e.g. smart glasses. Moreover, the polarization-based VLC can be applied to any illuminating light sources, thereby eliminating the dependency on LED. This paper presents the VLP system PIXEL, which realizes our idea. In PIXEL, we develop three techniques, each of which addresses a design challenge: 1) a novel color-based modulation scheme to handle users? mobility, 2) an adaptive downsampling algorithm to tackle the uneven sampling problem of wearables? low-cost camera and 3) a computational optimization method for the positioning algorithm to enable real-time processing. We implement PIXEL?s hardware using commodity components and develop a software program for both smartphone and Google glass. Our experiments based on the prototype show that PIXEL can provide accurate realtime VLP for wearables and smartphones with camera resolution as coarse as 60 pixel x 80 pixel and CPU frequency as low as 300MHz. <s> BIB025 </s> A State-of-the-Art Survey on Multidimensional Scaling-Based Localization Techniques <s> B. Local Positioning Systems <s> This work presents a low power outdoor localization system that implements a power management technique in order to control the wakeup and sleep of the different modules in the system. Through this technique, the system achieves 6.7 µA in sleep mode. A new weighted least mean squares solution algorithm that is based on received signal strength indicator (RSSI) measurements is introduced. Both simulation and measurement results are presented. It is shown that over 50% improvement in position estimation is achieved using the proposed weighted least mean squares algorithm. <s> BIB026 </s> A State-of-the-Art Survey on Multidimensional Scaling-Based Localization Techniques <s> B. Local Positioning Systems <s> In this paper, we investigate the problem of indoor positioning using visible light systems. The directional detector array we use is comprised of a number of receiving elements, each consisting of an aperture and a photo diode, which are arranged to offer good angular diversity, and can be implemented within a compact receiver structure [1]. The receiving elements receive the light from a number of white LEDs, which are typically attached to the ceiling, and which act as anchors. In order to get an indication of the received signal strengths of the different LEDs, we average the received signals over time. The relative signal strengths in the different receiving elements do not only provide information on the distance between the LEDs and the detector array, but also about the angle-of-arrival of the light. By combining the information of the receiving elements, the position of the detector can be estimated. In order to assess the accuracy of positioning algorithms based on this approach, we derive the Cramer-Rao lower bound on the position accuracy. Assuming the white LEDs transmit an optical power of 1 W, and the time averaging is done over 1 millisecond, an accuracy of the order of a centimetre can be achieved. <s> BIB027 </s> A State-of-the-Art Survey on Multidimensional Scaling-Based Localization Techniques <s> B. Local Positioning Systems <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> BIB028 </s> A State-of-the-Art Survey on Multidimensional Scaling-Based Localization Techniques <s> B. Local Positioning Systems <s> Limiting the knowledge of individual nodes is a major concern for the design of distributed algorithms. With the LOCAL model, theoretical research already established a common model of locality that has gained little practical relevance. As a result, practical research de facto lacks any common locality model. The only common denominator among practitioners is that a local algorithm is distributed with a restricted scope of interaction. This article closes the gap by introducing four practically motivated classes of locality that successively weaken the strict requirements of the LOCAL model. These classes are applied to categorize and survey 36 local algorithms from 12 different application domains. A detailed comparison shows the practicality of the classification and provides interesting insights. For example, the majority of algorithms limit the scope of interaction to at most two hops, independent of their locality class. Moreover, the application domain of algorithms tends to influence their degree of locality. <s> BIB029 </s> A State-of-the-Art Survey on Multidimensional Scaling-Based Localization Techniques <s> B. Local Positioning Systems <s> Summary ::: In recent years, wireless sensor networks (WSNs) have attracted the attention of both the research community and the industry, and this has eventually lead to the widespread use of WSNs in various applications. The significant advancements in WSNs and the advantages brought by WSNs have also enabled the rapid development of underwater acoustic sensor networks (UASNs). In UASNs, in addition to deployment, determining the locations of underwater sensor nodes after they have been deployed is important since it plays a critical role in many applications. Various localization techniques have been proposed for UASNs, and each one is suitable for specific scenarios and has unique challenges. In this paper, after presenting an overview of potential UASN applications, a survey of the deployment techniques and localization algorithms for UASNs has been presented based on their major advantages and disadvantages. Finally, research challenges and open research issues of UASNs have been discussed to provide an insight into future research opportunities. <s> BIB030 </s> A State-of-the-Art Survey on Multidimensional Scaling-Based Localization Techniques <s> B. Local Positioning Systems <s> Underwater wireless technologies demand to transmit at higher data rate for ocean exploration. Currently, large coverage is achieved by acoustic sensor networks with low data rate, high cost, high latency, high power consumption, and negative impact on marine mammals. Meanwhile, optical communication for underwater networks has the advantage of the higher data rate albeit for limited communication distances. Moreover, energy consumption is another major problem for underwater sensor networks, due to limited battery power and difficulty in replacing or recharging the battery of a sensor node. The ultimate solution to this problem is to add energy harvesting capability to the acoustic-optical sensor nodes. Localization of underwater sensor networks is of utmost importance because the data collected from underwater sensor nodes is useful only if the location of the nodes is known. Therefore, a novel localization technique for energy harvesting hybrid acoustic-optical underwater wireless sensor networks (AO-UWSNs) is proposed. AO-UWSN employs optical communication for higher data rate at a short transmission distance and employs acoustic communication for low data rate and long transmission distance. A hybrid received signal strength (RSS) based localization technique is proposed to localize the nodes in AO-UWSNs. The proposed technique combines the noisy RSS based measurements from acoustic communication and optical communication and estimates the final locations of acoustic-optical sensor nodes. A weighted multiple observations paradigm is proposed for hybrid estimated distances to suppress the noisy observations and give more importance to the accurate observations. Furthermore, the closed form solution for Cramer-Rao lower bound (CRLB) is derived for localization accuracy of the proposed technique. <s> BIB031 </s> A State-of-the-Art Survey on Multidimensional Scaling-Based Localization Techniques <s> B. Local Positioning Systems <s> Wireless Local Area Network (WLAN) has become a promising choice for indoor positioning as the only existing and established infrastructure, to localize the mobile and stationary users indoors. However, since WLAN has been initially designed for wireless networking and not positioning, the localization task based on WLAN signals has several challenges. Amongst the WLAN positioning methods, WLAN fingerprinting localization has recently achieved great attention due to its promising results. WLAN fingerprinting faces several challenges and hence, in this paper, our goal is to overview these challenges and the state-of-the-art solutions. This paper consists of three main parts: 1) Conventional localization schemes; 2) State-of-the-art approaches; 3) Practical deployment challenges. Since all the proposed methods in WLAN literature have been conducted and tested in different settings, the reported results are not equally comparable. So, we compare some of the main localization schemes in a single real environment and assess their localization accuracy, positioning error statistics, and complexity. Our results depict illustrative evaluation of WLAN localization systems and guide to future improvement opportunities. <s> BIB032 </s> A State-of-the-Art Survey on Multidimensional Scaling-Based Localization Techniques <s> B. Local Positioning Systems <s> Recently, visible light communication (VLC) has gradually become a research hotspot in indoor environments because its advantages of illumination and relative high positioning accuracy. But unfortunately, in the matter of algorithm complexity and positioning accuracy, most existing VLC-based systems fail to deliver satisfactory performance. Moreover, the majority of visible light positioning algorithm in them are based on two-dimensional (2-D) plane. In addition, some of the systems realize 3-D positioning on the base of various sensors or hybrid complex algorithm. These methods greatly reduce the robustness of VLC system. To solve these problems, a novel VLC positioning system based on modified particle swarm optimization (PSO) algorithm is put forward in this article. PSO is a powerful population-based stochastic approach to solve the global optimization problems, such as VLC-based indoor positioning, which can be transformed into a global optimization problem. Our simulation shows that the average distance error is 3.9 mm within 20 iterations in an indoor environment of ${\text{3}\,\text{m}}\times \text{3}\,{\text{m}}\times \text{4}\,{\text{m}}$ . And the positioning results prove that this system can prove high localization accuracy and significantly lower the algorithm complexity. Moreover, in the experiment, we come up with a solution that using Kalman filter to deal with the unstable received signals. Our experiment result proves the mentioned system satisfies the requirement of cm-level indoor positioning. Therefore, this scheme may be considered as one of the competitive indoor positioning candidates in the future. <s> BIB033 </s> A State-of-the-Art Survey on Multidimensional Scaling-Based Localization Techniques <s> B. Local Positioning Systems <s> Recently, several positioning systems based on visible light communications (VLC) have been proposed, and most of them are based on received signal strength (RSS) because of its simplicity and high accuracy. In order to improve the accuracy further, a differential detection-based positioning algorithm is proposed. It can reduce positioning instability caused by light intensity fluctuation and the area outside the light-emitting diode (LED) cell can also be positioned. Experimental results show that the proposed method can improve the positioning accuracy from 10.0 to 4.0 cm and reduce the standard deviation from 9.0 to 2.5 cm. Meanwhile, the positioning accuracy outside the cell can reach 10.0 cm or less. <s> BIB034 </s> A State-of-the-Art Survey on Multidimensional Scaling-Based Localization Techniques <s> B. Local Positioning Systems <s> Advances in visible light communication (VLC) technology and the ubiquity of illumination facility have led to a growing interest in VLC-based indoor positioning. Numerous techniques have been proposed to obtain better system performance. In this paper, we survey over 100 papers ranging from pioneering papers to the state-of-the-art in the field to present the positioning technology. Not only the light emitting diode technology, modulation method and types of receivers are compared but also a novel taxonomy method is proposed. In this paper, VLC-based indoor positioning systems (VLC-based-IPSs) are classified based on the methods used: 1) mathematical method; 2) sensor-assisted method; and 3) optimization method. Different from other survey works, we emphasize and analyze the accuracy of VLC-based-IPS in the experiment and simulation environments. Meanwhile, this paper illustrates challenges, countermeasures, and lessons learned. <s> BIB035 </s> A State-of-the-Art Survey on Multidimensional Scaling-Based Localization Techniques <s> B. Local Positioning Systems <s> In this paper, a received signal strength (RSS) based localization technique is investigated for underwater optical wireless sensor networks (UOWSNs) where optical noise sources (e.g., sunlight, background, thermal, and dark current) and channel impairments of seawater (e.g., absorption, scattering, and turbulence) pose significant challenges. Hence, we propose a localization technique that works on the noisy ranging measurements embedded in a higher dimensional space and localize the sensor network in a low dimensional space. Once the neighborhood information is measured, a weighted network graph is constructed, which contains the one-hop neighbor distance estimations. A novel approach is developed to complete the missing distances in the kernel matrix. The output of the proposed technique is fused with Helmert transformation to refine the final location estimation with the help of anchors. The simulation results show that the root means square positioning error (RMSPE) of the proposed technique is more robust and accurate compared to baseline and manifold regularization. <s> BIB036 </s> A State-of-the-Art Survey on Multidimensional Scaling-Based Localization Techniques <s> B. Local Positioning Systems <s> Cellular systems evolved from a dedicated mobile communication system to an almost omnipresent system with unlimited coverage anywhere and anytime for any device. The growing ubiquity of the network stirred expectations to determine the location of the mobile devices themselves. Since the beginning of standardization, each cellular mobile radio generation has been designed for communication services, and satellite navigation systems, such as Global Positioning System (GPS), have provided precise localization as an add-on service to the mobile terminal. Self-contained localization services relying on the mobile network elements have offered only rough position estimates. Moreover, satellite-based technologies suffer a severe degradation of their localization performance in indoors and urban areas. Therefore, only in subsequent cellular standard releases, more accurate cellular-based location methods have been considered to accommodate more challenging localization services. This survey provides an overview of the evolution of the various localization methods that were standardized from the first to the fourth generation of cellular mobile radio, and looks over what can be expected with the new radio and network aspects for the upcoming generation of fifth generation. <s> BIB037 </s> A State-of-the-Art Survey on Multidimensional Scaling-Based Localization Techniques <s> B. Local Positioning Systems <s> Recently, a camera or an image sensor receiver based optical wireless communications (OWC) techniques have attracted particular interest in areas such as the internet of things, indoor localization, motion capture, and intelligent transportation systems. As a supplementary technique of high-speed OWC based on photo-detectors, communications hinging on image sensors as receivers do not need much modification to the current infrastructure, such that the implementation complexity and cost are quite low. Therefore, in this paper, we present a comprehensive survey of optical camera communication (OCC) techniques, and their use in localization, navigation, and motion capture. This survey is distinguishable from the existing reviews on this topic by covering multiple aspects of OCC and its various applications. The first part of the paper focuses on the standardization, channel characterization, modulation, coding, and synchronization of OCC systems while the second part of the article presents the literature on OCC based localization, navigation, and motion capture. Finally, in the last part of the paper, we present the challenges and future research directions of OCC. <s> BIB038
LPS provide location information to the user with the help of base stations or anchors which can generate beacon signals. The coverage of LPS is limited, and localization is achieved only within the coverage area of the network. LPS can be categorized based on different network criteria, here we broadly classify them by availability of computation, environment, and medium for transmission. 1) Computation: LPS can be broadly categorized into distributed and centralized techniques, based on the computation BIB017 . In distributed positioning systems every user can determine its location with the help of geographically distributed anchors. Many distributed positioning systems have been presented in the past for WSNs such as BIB005 and BIB029 . Unlike distribute LPS, in centralized positioning systems, each user determines its neighborhood information using time of arrival (ToA), angle of arrival (AoA), time difference of arrival (TDoA), and received signal strength (RSS). The neighborhood information is collected at a centralized station which finds out the location of the user and shares the location information with the user. 2) Environment: Since every positioning system heavily depends on the environment, different LPS have been developed for different environments. These LPS can be divided into three categories based on the environment, i.e., outdoor LPS, indoor LPS and underwater LPS. • Outdoor LPS: Localization in outdoor is usually provided by GPS with an accuracy of 5 to 10 meters. With the help of wide area augmentation systems, the accuracy is improved to the range of 1 to 8 meters. But still this accuracy is not sufficient for certain applications, therefore, NavCom provided a local differential GPS based outdoor positioning system with an accuracy of 1 centimeter. However, the power constraint and higher cost generally do not allow the use of GPS receiver for small sensor devices. Therefore, GPS less outdoor positioning was proposed in BIB002 . In BIB026 the authors proposed a low power consumption localization scheme for outdoor positioning by using a power management scheme. Unfortunately, till date, the academic proposals BIB009 , BIB015 as well as the industrial practices  ,  In addition, the accuracy of localization algorithms also depends on many other factors which include propagation losses, number of anchor nodes, the location of anchor nodes, time synchronization, and scheduling BIB023 . Thus, many researchers developed localization schemes which take into account the above factors for acoustic waves-based underwater localization. Hence, a few brief surveys are presented on this subject such as BIB018 and BIB030 . However, the speed of acoustic waves is slow and therefore it leads to the development of high speed underwater optical wireless communication (UOWC) systems. In comparison with the acoustic systems, UOWC can support higher data rates up to several Gbps in clear waters with little to no scattering. However, UOWC suffers from low transmission range and require accurate pointing between the transmitter and the receiver. To provide the localization capabilities in UOWC systems, various localization schemes have recently been developed such as BIB031 and BIB036 . 3) Transmission Medium: LPS can also be categorized based on the transmission medium. • Radio Frequency (RF) based LPS: The popular LPS based on RF technology consists of cellular networks based LPS, wireless local area networks (WLANs) based LPS and radio frequency identification (RFID) based LPS. -Cellular networks based LPS: LPS based on cellular networks has been discussed for more than a decade. Initially, the position of a mobile terminal was determined using global system for mobile communication (GSM)  . Indeed the techniques discussed in BIB010 influenced the standardization of universal mobile telecommunications system (UMTS). In cellular network based LPS, the location of the mobile station is determined by the base station by using the cell geometries. Interested readers are referred to BIB037 , which is the most recent survey article on cellular-based LPS. -WLANs based LPS: WLAN-based LPS are very popular among other LPS due to its established infrastructure. In BIB003 the authors proposed a LPS which can locate and track the user using the nearest neighbors technique. The accuracy of this WLAN based LPS is 2 to 3 meters. There are several other WLAN based LPS, for the interested readers we refer to the detailed surveys presented in BIB012 ,  BIB014 BIB020 BIB032 on this subject. -RFID based LPS: RFID technology is mostly employed in harsh indoor scenarios such as offices, hospitals, subways etc. RFID based technology provides cheap and adaptable identification of a device or an individual BIB008 . For supporting indoor and outdoor localization in real time, WhereNet is the popular real-time location system (RTLS) offered by Zebra technology [77] which is based on RFID tags and differential time of arrival (DToA) technique. • Acoustic based LPS: Acoustic waves are also used in localization systems to locate a node or a user BIB024  BIB016 BIB004 BIB019 BIB006 . It is known that bats use acoustic signals to navigate. Inspired by this, Active Bat localization system was developed by AT & T based on acoustic signals, which provides 3-dimensional localization. Active Bat localization system consists of an acoustic system and triangulation approach for localization. The distance between the transmitter and receiver is measured through ToA measurements. Some other major acoustic based LPS are Cricket BIB004 , Sonitor BIB019 , and DOLPHIN BIB006 . • Optical LPS: Optical LPS are becoming dominant LPS which covers a wide range of applications. Optical LPS can further be classified into visible light communications (VLC) based LPS and infrared-based LPS. -Visible Light based LPS: The advancement of visible light technology has led to the development of visible light based communication (VLC). Based on the universality and recent research on VLC, LPS are considered to be an important feature of VLC. A theoretical accuracy of centimeters has been reported in BIB033 BIB027 BIB034 by using VLC for LPS. Recently, a number of practical LPS such as Luxapose BIB021 , PIXEL BIB025 , Epsilon BIB022 , and LIPS BIB028 based on VLC are proposed. Epsilon was the first visible light based LPS which can achieve an accuracy of 0.4 to 0.8 meters. Luxapose, LIPS, and PIXEL achieve an accuracy of 0.1, 0.4, and 0.2 meters respectively. It should be noted that every LPS based on visible light strongly depends on the light emitting diode (LED) technology, types of receivers, and modulation method used. Interested readers are referred to BIB035 and BIB038 where the authors have reviewed a number of LPS based on VLC. -Infrared (IR) based LPS: Infrared (IR) based LPS BIB013 BIB001  [96] BIB011 BIB007 are the most common localization systems owing to the availability of the IR technology for numerous gadgets. IR based localization system requires line of sight (LOS) connection between the transmitter and receiver in the absence of any kind of interference. Some of commercial IR based localization and tracking systems are Firefly [96] , OPTOTRAK BIB011 , and infrared indoor source local positioning system (IRIS_LPS) BIB007 . Major issues with optical LPS include multipath reflections, synchronization, coverage, and privacy. For example, optical LPS require line of sight (LoS) links for range estimation. However, LoS link may not always be available due to the multi-path effect caused by light reflections from various surfaces. Similarly, synchronization is also a significant issue for time-based ranging in optical LPS because it is challenging to synchronize all the transmitters and the receivers. Limited coverage of the LED transmitters is also of major concern due to their directive nature, for optical LPS.