Presence Detection with Bluetooth Low Energy: A Review and Experiment

Bluetooth is one of the most ubiquitous technologies in smart phone today and its prominence in other devices is rising rapidly. It has become the De Facto technology used when there is need for device-to-device communication. However, the evolving standard has much more to offer. Bluetooth can power many applications due to capabilities. A key metric of Bluetooth is the Received Signal Strength Indicator (RSSI) and depending on the readings one can infer locality. This study evaluates existing research that attempts localization implemented using the Bluetooth protocol and the metrics that power those applications. A proof-of-concept software is developed to further investigate the feasibility of presence detection using Bluetooth Low Energy without connection to a device.&nbsp

Unified cooperative location system

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para a obtenção do Grau de Mestre em Engenharia Informática.The widespread use of smaller, less expensive, and more capable mobile devices, has opened the door for more complex and varied mobile computing applications. Additionally, manufacturers are increasingly equipping these handheld devices with every type of wireless connectivity and sensors that can be explored for providing more complex services. In recent years, several techniques for location estimation have been developed, providing different degrees of accuracy. Some of these solutions require the installation of specific hardware in the environment, while others explore the existing infrastructure. In particular, it is possible to explore the existing communication infrastructure to build a location system relying on signal strength measures. However, while several systems already exist to locate users based on different approaches, there is no single one that is good for every situation while providing high accuracy, low cost and ubiquitous coverage. Not only that, but very few research has been made regarding on how a group of users can cooperate to improve accuracy or reduce energy consumption while using the location system. This work presents the Unified Cooperative Location System, a modular and extensible location system. Its modular design can use every available technology on each device and different algorithms for location estimation. This approach allows to provide location services with high availability by relying on different technologies. It also allows to reduce the energy consumption on devices by sharing the responsibility of executing energy-heavy operations. The system also includes an information exchange mechanism, allowing devices to gather location information from nearby users, like GPS or Wi-Fi, which would otherwise be unavailable for some. The results of our experiences show that the possibility of exchanging GSM information provides a practical solution for location estimation based on multiple GSM signals, thus significantly increasing location accuracy with this technology

Asynchronous Ultrasonic Trilateration for Indoor Positioning of Mobile Phones

Spatial awareness is fast becoming the key feature on today‟s mobile devices. While accurate outdoor navigation has been widely available for some time through Global Positioning Systems (GPS), accurate indoor positioning is still largely an unsolved problem. One major reason for this is that GPS and other Global Navigation Satellite Systems (GNSS) systems offer accuracy of a scale far different to that required for effective indoor navigation. Indoor positioning is also hindered by poor GPS signal quality, a major issue when developing dedicated indoor locationing systems. In addition, many indoor systems use specialized hardware to calculate accurate device position, as readily available wireless protocols have so far not delivered sufficient levels of accuracy. This research aims to investigate how the mobile phone‟s innate ability to produce sound (notably ultrasound) can be utilised to deliver more accurate indoor positioning than current methods. Experimental work covers limitations of mobile phone speakers in regard to generation of high frequencies, propagation patternsof ultrasound and their impact on maximum range, and asynchronous trilateration. This is followed by accuracy and reliability tests of an ultrasound positioning system prototype.This thesis proposes a new method of positioning a mobile phone indoors with accuracy substantially better than other contemporary positioning systems available on off-theshelf mobile devices. Given that smartphones can be programmed to correctly estimate direction, this research outlines a potentially significant advance towards a practical platform for indoor Location Based Services. Also a novel asynchronous trilateration algorithm is proposed that eliminates the need for synchronisation between the mobile device and the positioning infrastructure

TDoA Based Positioning using Ultrasound Signals and Wireless Nodes

In this paper, a positioning technique based on Time Difference of Arrival (TDoA) measurements is analyzed. The proposed approach is designed to consent range and position estimation, using ultrasound transmissions of a stream of chirp pulses, received by a set of wireless nodes. A potential source of inaccuracy introduced by lack of synchronization between transmitting node and receiving nodes is identified and characterized. An algorithm to identify and correct such inaccuracies is presented.Comment: Preprin

A Hybrid Indoor Location Positioning System

Indoor location positioning techniques have experienced impressive growth in recent years. A wide range of indoor positioning algorithms has been developed for various applications. In this work a practical indoor location positioning technique is presented which utilizes off-the-shelf smartphones and low-cost Bluetooth Low Energy (BLE) nodes without any further infrastructure. The method includes coarse and fine modes of location positioning. In the coarse mode, the received signal strength (RSS) of the BLE nodes is used for location estimation while in the fine acoustic signals are utilized for accurate positioning. The system can achieve centimeter-level positioning accuracy in its fine mode. To enhance the system’s performance in noisy environments, two digital signal processing (DSP) algorithms of (a) band-pass filtering with audio pattern recognition and (b) linear frequency modulated chirp signal with matched filter are implemented. To increase the system’s robustness in dense multipath environments, a method using data clustering with sliding window is employed. The received signal strength of BLE nodes is used as an auxiliary positioning method to identify the non-line-of-sight (NLoS) propagation paths in the acoustic positioning mode. Experimental measurement results in an indoor area of 10 m2 indicate that the positioning error falls below 6 cm

Smart Indoor Positioning/Location and Navigation: A Lightweight Approach

In this paper a new location indoor system is presented, which shows the position and orientation of the user in closed environments, as well as the optimal route to his destination through location tags. This system is called Labelee, and it makes easier the interaction between users and devices through QR code scanning or by NFC tag reading, because this technology is increasingly common in the latest smartphones. With this system, users could locate themselves into an enclosure with less interaction

Enhancing Indoor Localisation: a Bluetooth Low Energy (BLE) Beacon Placement approach

Indoor location-based services have become increasingly vital in various sectors, including industries, healthcare, airports, and crowded infrastructures, facilitating asset tracking and user navigation. This project addresses the critical challenge of optimising beacon placement for indoor location, employing Bluetooth technology as the communication protocol. The significance of this research lies in the effi ciency and accuracy that an optimised beacon layout can provide, enhancing the effectiveness of indoor positioning systems. The algorithm developed takes into con sideration materials attenuation, coverage and Line of Sight (LOS) conditions to optimise its layouts. Experimental validation of the algorithm’s performance was conducted by comparing two beacon layouts: one optimised by the algorithm and the other manually arranged by individuals with empirical knowledge in the field. The experiment considered three distinct positions within the schematic, allowing for a comprehensive assessment of the optimised layout’s superior performance. The results of this research offer insights into the potential of the algorithm to revolu tionise indoor location services, providing a more reliable and cost-effective solution for a multitude of applications.Os serviços de localização em ambientes internos tornaram-se cada vez mais essenciais em vários setores, incluindo indústrias, cuidados de saúde, aeroportos e infraestruturas movimentadas, facilitando o rastreamento de objetos e a navegação de utilizadores. Este projeto aborda o desafio crítico da otimização da colocação de beacons para localização em ambientes internos, utilizando a tecnologia Bluetooth como protocolo de comunicação. A importância desta pesquisa reside na eficiência e precisão que uma disposição otimizada de beacons pode proporcionar, melhorando a eficácia de sistemas de posicionamento em ambientes internos. O algoritmo desenvolvido leva em consideração a atenuação de materiais, a cobertura e as condições de visão direta para otimizar as suas disposições. A validação experimental do desempenho do algoritmo foi realizada ao comparar duas disposições de beacons: uma otimizada pelo algoritmo e outra organizada manualmente por indivíduos com conhecimento empírico na área. A experiência considerou três posições distintas no esquema, permitindo uma avaliação abrangente do desempenho superior da disposição otimizada. Os resultados desta pesquisa oferecem descobertas importantes sobre o potencial do algoritmo para revolucionar os serviços de localização em ambientes internos, proporcionando uma solução mais confiável e econômica para uma variedade de aplicações

A survey on acoustic positioning systems for location-based services

Positioning systems have become increasingly popular in the last decade for location-based services, such as navigation, and asset tracking and management. As opposed to outdoor positioning, where the global navigation satellite system became the standard technology, there is no consensus yet for indoor environments despite the availability of different technologies, such as radio frequency, magnetic field, visual light communications, or acoustics. Within these options, acoustics emerged as a promising alternative to obtain high-accuracy low-cost systems. Nevertheless, acoustic signals have to face very demanding propagation conditions, particularly in terms of multipath and Doppler effect. Therefore, even if many acoustic positioning systems have been proposed in the last decades, it remains an active and challenging topic. This article surveys the developed prototypes and commercial systems that have been presented since they first appeared around the 1980s to 2022. We classify these systems into different groups depending on the observable that they use to calculate the user position, such as the time-of-flight, the received signal strength, or the acoustic spectrum. Furthermore, we summarize the main properties of these systems in terms of accuracy, coverage area, and update rate, among others. Finally, we evaluate the limitations of these groups based on the link budget approach, which gives an overview of the system's coverage from parameters such as source and noise level, detection threshold, attenuation, and processing gain.Agencia Estatal de InvestigaciónResearch Council of Norwa