996 research outputs found
An integrated method for short-term prediction of road traffic conditions for intelligent transportation systems applications
The paper deals with the short-term prediction of road traffic conditions within Intelligent Transportation Systems applications. First, the problem of traffic modeling and the potential of different traffic monitoring technologies are discussed. Then, an integrated method for short-term traffic prediction is presented, which integrates an Artificial Neural Network predictor that forecasts future states in standard conditions, an anomaly detection module that exploits floating car data to individuate possible occurrences of anomalous traffic conditions, and a macroscopic traffic model that predicts speeds and queue progressions in case of anomalies. Results of offline applications on a primary Italian motorway are presented
Estimation And Tracking Algorithm For Autonomous Vehicles And Humans
Autonomous driving systems have experienced impressive growth in recent years. The present research community is working on several challenging aspects, such as, tracking, localization, path planning and control. In this thesis, first, we focus on tracking system and present a method to accurately track a moving vehicle. In the vehicle tracking, considering the proximity of surrounding vehicles, it is critical to detect their unusual maneuvers as quickly as possible, especially when autonomous vehicles operate among human-operated traffic. In this work, we present an approach to quickly detect lane-changing maneuvers of the nearby vehicles. The proposed algorithm is based on the optimal likelihood ratio test, known as Page test. Second, we consider another form of tracking: tracking the movements of humans in indoor settings. Indoor localization of staff and patients based on radio frequency identification (RFID) technology has promising potential application in the healthcare sector. The use of an active RFID in real-time indoor positioning system without any sacrifice of localization accuracy is intended to provide security, guidance and support service to patients. In this paper maximum likelihood estimation along with its Cramer-Rao lower bound of the locations of active RFID tags are presented by exploring the received signal strength indicator which is collected at the readers. The performance of real-time localization system is implemented by using an extended Kalman filter (EKF)
A Survey of Positioning Systems Using Visible LED Lights
© 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.As Global Positioning System (GPS) cannot provide satisfying performance in indoor environments, indoor positioning technology, which utilizes indoor wireless signals instead of GPS signals, has grown rapidly in recent years. Meanwhile, visible light communication (VLC) using light devices such as light emitting diodes (LEDs) has been deemed to be a promising candidate in the heterogeneous wireless networks that may collaborate with radio frequencies (RF) wireless networks. In particular, light-fidelity has a great potential for deployment in future indoor environments because of its high throughput and security advantages. This paper provides a comprehensive study of a novel positioning technology based on visible white LED lights, which has attracted much attention from both academia and industry. The essential characteristics and principles of this system are deeply discussed, and relevant positioning algorithms and designs are classified and elaborated. This paper undertakes a thorough investigation into current LED-based indoor positioning systems and compares their performance through many aspects, such as test environment, accuracy, and cost. It presents indoor hybrid positioning systems among VLC and other systems (e.g., inertial sensors and RF systems). We also review and classify outdoor VLC positioning applications for the first time. Finally, this paper surveys major advances as well as open issues, challenges, and future research directions in VLC positioning systems.Peer reviewe
Low cost inertial-based localization system for a service robot
Dissertation presented at Faculty of Sciences and Technology of the New University of Lisbon
to attain the Master degree in Electrical and Computer Science EngineeringThe knowledge of a robot’s location it’s fundamental for most part of service robots. The success of tasks such as mapping and planning depend on a good robot’s position knowledge.
The main goal of this dissertation is to present a solution that provides a estimation of the robot’s location. This is, a tracking system that can run either inside buildings or outside them, not taking into account just structured environments. Therefore, the localization system takes into
account only measurements relative.
In the presented solution is used an AHRS device and digital encoders placed on wheels to make a estimation of robot’s position. It also relies on the use of Kalman Filter to integrate sensorial information and deal with estimate errors.
The developed system was testes in real environments through its integration on real robot. The results revealed that is not possible to attain a good position estimation using only low-cost inertial
sensors. Thus, is required the integration of more sensorial information, through absolute or relative measurements technologies, to provide a more accurate position estimation
Geometry-based localization for GPS outage in vehicular cyber physical systems
Vehicular localization has witnessed significant attention due to the growing number of location-based services in vehicular cyber physical systems (VCPS). In vehicular localization, GPS outage is a challenging issue considering the growing urbanization including high rise buildings, multilevel flyovers and bridges. GPS-free and GPS-assisted cooperative localization techniques have been suggested in the literature for GPS outage. Due to the cost of infrastructure in GPS-free techniques, and the absence of location aware neighbors in cooperative techniques, efficient and scalable localization is a challenging task in VCPS. In this context, this paper proposes a geometry-based localization for GPS outage in VCPS (GeoLV). It is a GPS-assisted localization which reduces location-aware neighbor constraint of cooperative localization. GeoLV utilizes mathematical geometry to estimate vehicle location focusing on vehicular dynamics and road trajectory. The static and dynamic relocations are performed to reduce the impact of GPS outage on location-based services. A case study based comparative performance evaluation has been carried out to assess the efficiency and scalability of GeoLV. It is evident from the results that GeoLV handles both shorter and longer GPS outage problem better than the state-of-the-art techniques in VCPS
Research on port AGV composite positioning based on UWB/RFID
In recent years, ports in various countries have successively carried out research and
application of fully automated terminal. The terminal adopts the "Double car shore
bridge + AGV + ARMG" automation process, which is the most widely used and
relatively mature fully automated solution. At present, the AGV navigation of the
terminal is based on RFID magnetic nail positioning and the accuracy is good. However,
nowadays UWB technology has become the most popular technology in ranging and
positioning. The research in this work is based on UWB/RFID composite positioning,
which is mainly used for the specific localization tasks in the port and it can accurately
locate the position of the AGV.
This MSc work studies the UWB positioning system first and then researches the
traditional 3D positioning algorithm. Importance contribution expressed by 3D TOA
localization algorithm. For RFID system, this connection between the reader and the
carrier is designed, and the reference tag is buried. At last, data-based on RFID
localization algorithm in scene analysis method is adopted for positioning. Secondly,
the basis of the composite positioning system is data fusion technology. The most
widely used and mature fusion algorithm is the Kalman filter algorithm and Particle
filter. Finally, the experimental analysis of UWB and RFID composite positioning
system is implemented. The results indicate that UWB and RFID composite positioning
system can reduce the cost of the positioning system. Higher positioning accuracy and
robustness are characterizing the developed system.Nos últimos anos, portos de vários países realizaram sucessivamente pesquisas e
aplicações de terminais totalmente automatizados. O terminal adota o processo de
automação "Double car shore bridge + AGV + ARMG", que é a solução totalmente
automatizada mais amplamente utilizada e relativamente madura. Atualmente, a
navegação AGV do terminal é baseada no posicionamento da etiqueta RFID e a
precisão é boa. No entanto, hoje em dia, a tecnologia UWB tornou-se na tecnologia
mais popular relativamente ao alcance e posicionamento. A pesquisa neste trabalho é
baseada no posicionamento composto por UWB / RFID, usado principalmente para
tarefas de localização específicas nos portos, podendo desta forma localizar-se com
precisão a posição do AGV.
Este projeto de mestrado estuda em primeiro lugar o sistema de posicionamento UWB,
e depois um algoritmo tradicional de posicionamento 3D. A contribuição da
importância expressa pelo algoritmo de posicionamento “time of arrival” (TOA) 3D foi
proposta. Para o sistema de posicionamento RFID, a conexão entre o leitor e a
transportadora é projetada e a etiqueta de referência é ocultada. Por fim, o algoritmo de
“k-nearest neighbor” baseado numa base de dados e no método de análise de cena é
adotado para realizar o posicionamento. Em segundo lugar, a base do sistema de
posicionamento composto é a tecnologia de fusão de dados. O algoritmo de fusão mais
amplamente utilizado e maduro é o algoritmo de filtro Kalman e o filtro de partículas.
Finalmente, é realizada a análise experimental do sistema de posicionamento composto
UWB e RFID. Os resultados experimentais mostram que o sistema de posicionamento
composto UWB e RFID pode reduzir o custo do sistema de posicionamento. O sistema
desenvolvido é caracterizado por uma maior precisão de posicionamento e robustez
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