一种基于RFID的室内车载监控系统定位方法的设计与实现

室内定位是智能家居系统中实现居境信息自主巡检的基础支撑技术。针对现有室内定位算法的不足,提出了一种基于RFID的新型室内定位方法。该方法建立基于RFID标签映射的地面坐标,借助电子罗盘获取车载系统方向,通过向量方法计算出车载系统的中心位置,有效地解决了室内定位的精度与稳定性问题。基于该方法,设计并实现了一个室内车载监控系统,验证了算法的有效性。     

Localization of RFID-equipped assets during the operation phase of facilities

Indoor localization has gained importance as it has the potential to improve various processes related to the lifecycle management of facilities and to deliver personalized and location-based services (LBSs). Radio Frequency Identification (RFID) based systems, on the other hand, have been widely used in different applications in construction and maintenance. This paper investigates the usage of RFID technology for indoor localization of RFID equipped assets during the operation phase of facilities. The location-related data on RFID tags attached to assets are extracted from a Building Information Model (BIM) and can provide context-aware information inside the building which can improve Facilities Management (FM) processes. First, using the current location of the assets saved on the tags attached to fixed assets, an FM personnel is able to read tags from a distance and locate them on a floor plan. Fixed tags with known positions act as reference tags for RFID reader localization techniques. In this scenario, the user can also estimate his/her location by scanning the surrounding reference tags. Furthermore, the paper investigates an approach to locate moveable assets using received signals from available reference tags in the building based on pattern matching and clustering algorithms. As a result, a user equipped with an RFID reader is able to estimate his/her location, as well as the location of target assets, without having access to any Real-Time Location System (RTLS) infrastructure. Several case studies are used to demonstrate the feasibility of the proposed methods.     

基于RFID的校园导航系统的设计与实现

随着GIS、LBS技术和移动互联网技术等核心技术的发展,服务于普通大众的个人导航系统成为应用热点。室内行走引导是个人导航系统的核心之一,其中涉及的室内定位技术一直是研究的难点之一。基于固定式RFID标签群,生成室内位置地图,将随身移动式RFID读写器和个人智能手机相结合,完成室内定位、路径计算和导航提醒。基于上述设计方案,完成了一个基于RFID的南京大学校园导航系统,并将其投入了实际使用。     

轻量级移动RFID认证协议研究设计

为解决移动射频识别（Mobile RFID）系统中信息通过无线信道传输所引发的安全与隐私问题,提出一种基于伪随机函数的轻量级移动RFID认证协议,实现后台服务器、阅读器与标签之间的双向认证。该协议中的运算主要集中在后台服务器和阅读器,可以有效地控制标签成本。安全性分析表明,该协议可以有效抵抗位置追踪、假冒、重放和同步化等攻击,并通过GNY逻辑进行了安全性证明。      

Hybrid indoor and outdoor location services for new generation mobile terminals

In the last years, an increasing interest in location services characterized the market of mobile ubiquitous devices (smartphones, handhelds, etc.). Several technologies and solutions have been developed to determine the position of mobile devices in their operating space, each with its specific degree of precision and accuracy. In this scenario, the ideal location service should be able of tracking the mobile terminal in any place it moves to, both indoors and outdoors. However, while outdoor location services have already achieved a satisfactory degree of technological maturity and effectiveness, a really ubiquitous location service that works satisfactorily in both indoor and outdoor scenarios is not yet available. In order to cope with the above challenge, this work proposes a hybrid location approach designed to choose and switch among multiple positioning technologies supported by the mobile device and available in the surrounding environment, in a dynamic and transparent way during the user movement. It combines signal strength–based fingerprinting techniques for indoor positioning together with traditional GPS-based positioning for the outdoor localization and performs opportunistic technology switching according to a count-and-threshold mechanism. The resulting solution is able to leverage the different features of the wireless networks and of the global positioning technologies, in order to provide ubiquitous location services across indoor and outdoor scenarios, as well as to minimize power consumption of the mobile device.     

Robust location tracking using a dual layer particle filter

Location awareness is an important part of many ubiquitous computing systems, but a perfect location system does not exist yet. Among many location tracking systems, we choose the radio frequency identification (RFID) system due to its various applications. However, the received signal strength indicator (RSSI) signals are too sensitive to the direction of the RFID reader’s antenna, the orientation of the RFID tag, human interference, and the diversity of propagation media that might be present. As a result, the direct use of a conventional particle filter does not provide satisfactory tracking performance. To overcome this problem, we suggest a dual layer particle filter, where the lower layer determines the tag’s location in the block level using a triangulation technique or the support vector machine (SVM) classifier, and the upper layer accurately estimates the tag’s location using the conventional particle filter within the pre-computed or classified block. This layered structure improves the location estimation and the tracking performance, because the location evidence from the lower layer effectively restricts the range of possible locations of the upper layer. We implement the proposed location tracking method using a ubiquitous RFID wireless network in an intelligent office, where several RFID readers are located in fixed locations and people or objects with active RFID tags move around the office. Extensive experiments show that the proposed location tracking method is so precise and robust that it is a good choice for person or object tracking in ubiquitous computing contexts. We also validate the usefulness of the proposed location tracking method by implementing it for a real-time people monitoring system in a noisy and complex steel mill.     

有源RFID定位系统设计与实现

随着数据业务和多媒体业务的快速增加,人们对定位与导航的需求日益增大。但是受定位时间、定位精度以及复杂环境等条件的限制,比较完善的定位技术目前还无法很好地利用,针对这些问题,在分析了现有几种典型的定位技术的特点和不足后,设计并实现了一套有源RFID定位系统。该系统以RFID技术为核心,利用读写器对标签进行定位。分析表明,该系统具有定位精度高,抗干扰能力强,定位范围大等特点,适用于多标签情况。     

Smartphone-based pedestrian tracking in indoor corridor environments

As the use of smartphones spreads rapidly, user localization becomes an important issue for providing diverse location-based services (LBS). While tracking users in outdoor environments is easily done with GPS, the solution for indoor tracking is not trivial. One common technique for indoor user tracking is to employ inertial sensors, but such a system needs to be capable of handling noisy sensors that would normally lead to cumulative locating errors. To reduce such error, additional infrastructure has often been deployed to adjust for these cumulative location errors. As well, previous work has used highly accurate sensors or sensors that are strapped to the body. This paper presents a stand-alone pedestrian tracking system, using only a magnetometer and an accelerometer in a smartphone in indoor corridor environments that are normally laid out in a perpendicular design. Our system provides reasonably accurate pedestrian locations without additional infrastructure or sensors. The experiment results show that the location error is less than approximately 7 m, which is considered adequate for indoor LBS applications.     

基于ZigBee的博物馆参观引导系统

目前人们在室外可以很精确地利用手机GPS功能规划自己的行程线路,但是室内环境复杂,存在多径现象,GPS很难在室内环境下定位。在前人对ZigBee室内定位的研究的基础上,利用指纹定位算法的原理,将ZigBee的室内定位技术应用于游客参观博物馆的场景中。系统采用ZigBee无线局域网,利用接收信号强度指示（Received Signal Strength Indication, RSSI）值及指纹定位算法,借助GPRS模块传输数据,利用数据库服务器处理数据,并通过安卓APP监控数据,使得游客在博物馆中的位置信息能及时地在APP上显示,同时根据游客在博物馆中位置,将游客参观的展品的信息推送给游客。测试结果表明,系统运行良好,基本符合预期要求。     

一种带有GPS的智能手机监控系统与方法

本文提出了一种带有GPS的智能手机监控系统及方法。该系统包含服务器平台和带有GPS的智能手机终端,实现实时位置查询、定时位置查询、周期位置上报,区域报警功能、终端初始化、按键设置、呼入呼出设置、用户管理、系统初始化、终端登录、SOS报警和缺电及关机报警等功能。同时本系统规定了一系列服务器平台和智能手机终端的信息交互流程。经实验验证,本系统与方法能够应用在多种型号的带有GPS的智能手机终端上,功能完善,真正实现位置监控与安全管理。     

基于MSP430的无源RFID考勤系统

随着信息技术的发展,智能化的考勤系统已经成为现代化企业架构的必备设施.设计了一种基于MSP430单片机和TRF7960射频芯片的读卡器,实现了对支持ISO14443A协议无源电子标签的查询和防碰撞算法,读卡距离约8cm,最多允许2张卡片同时读卡.读卡器具有性能稳定、功耗低等特点,结合服务器端系统中间件和Web应用软件的开发,实现了一套考勤系统的完整解决方案.     

一种改进LANDMARC射频识别室内定位算法

在射频识别RFID室内定位环境中,LANDMARC定位算法的精度与选取的近邻参考标签数量有关。传统的算法仅仅局限于在小范围定位环境中选取3~5个参考标签,而在较大的定位环境中,距阅读器较远的相邻参考标签存在干扰近邻参考标签选取的情况,因此,需要选取较多的参考标签来辅助定位,然而随着选取参考标签数量的增加,定位误差越来越大。针对这一问题,在选取的参考标签中引入加权思想来优化计算过程中权重的分配,进而降低系统误差,提高定位精度。仿真实验结果表明,改进后的LANDMARC定位算法在选取较多参考标签的情况下具有较高的定位精度。     

An infrastructure for smart hospitals

In healthcare facilities most of the daily activities require strict coordination between clinicians, who often operate under heavy workloads and minimal workforce conditions in environments filled with increasingly complex technology. Ubiquitous Computing applications constitute a suitable solution for both reducing medical costs and improving patient safety by better supporting clinical processes. In this study we introduce an intelligent infrastructure for smart hospitals which implements basic services to optimize medical staff/patient interactions and grants ubiquitous and transparent access to clinical data stored in standard clinical databases. This infrastructure relies on the integration of Radio Frequency IDentification (RFID) and photosensor technologies to identify, locate and track clinicians and patients equipped with mobile devices and wearable RFID tags.     

Ubiquitous interaction with positioning and navigation using a novel light sensor-based information transmission system

This paper describes a novel light sensor-based information transmission system for indoor positioning and navigation with particular benefits for mobile and wearable computers. It can seamlessly extend outdoor GPS tracking to the indoor environment. In a novel manner, fluorescent light is used as the medium to transmit information, which is encoded by using a pulse-frequency modulation technique. The user receives the encoded light information through a photo-receiver. The information is passed into the wearable or mobile computer after the data is decoded. This information allows positioning information to be given to indoor mobile and wearable computers. We design an economical transmitter circuit by adding few components to a commercial electronic ballast circuit for fluorescent lamps with price of less than US $10. The propose system can be used in indoor guidance and navigation applications. Exemplary applications are included in the paper, with experimented results detailed.     

物联网中大规模RFID标签盘存方法研究

面向物联网应用,对大规模RFID标签盘存方法进行分析研究。首先介绍RFID系统基本原理,特别是大规模RFID标签盘存方法,分析标签盘存中所包括的移动标签识别、丢失标签监测和未识别标签监测问题;其次,从现实信道环境角度考虑,分别着重综述标签盘存方法研究现状,包括对移动标签识别方法、丢失标签监测方法、未识别标签监测方法进行对比分析,并指出本领域存在主要问题及未来研究给出建议。     

基于相位差测距的RFID室内定位系统设计

针对当前室内定位的广泛需求及传统室内定位技术的缺陷,设计了一种基于相位差测距的射频识别(RFID)室内定位系统.系统主要由RFID阅读器、电子标签、STM32模块组成,3个电子标签固定在特定位置作为信标节点,1个RFID阅读器作为移动节点发射与接收超高频信号,STM32模块根据测得的相位差计算相应的距离,并利用改进后的三边定位法,确定阅读器的位置.在实验室对进行了设计并测试,结果表明:该系统能很好地完成定位功能,定位精度达到厘米(cm)级,可满足众多领域的应用需求.     

EDIPS: an Easy to Deploy Indoor Positioning System to support loosely coupled mobile work

Loosely coupled mobile work is characterized by nomadic workers collaborating in sporadically and on-demand ways. Supporting nomadic workers’ interactions requires knowing the location of the potential collaborator; therefore, indoor/outdoor positioning systems play a key role. Locating persons in outdoor environments is well addressed by Global Positioning Systems (GPS); however, for the indoor scenario, the solution is not so clear. Although several proposals for indoor positioning have been reported in the literature, most of them demand important setup efforts. This article presents the Easy to Deploy Indoor Positioning System (EDIPS), a WiFi-based system able to support the typical location requirements involved in loosely coupled mobile work. EDIPS is aimed for fast deployment and real-time operations rather than for location accuracy. The system was preliminary evaluated as a support for locating medical interns’ in a simulated hospital. The results obtained indicate the solution is able to locate nomadic workers in an indoor scenario, with enough accuracy to support loosely coupled mobile work, while requiring minimal setup effort.     

High-precision identification of contextual information in location-aware engineering applications

This paper presents research that investigated algorithms for high-precision identification of contextual information in location-aware engineering applications. The primary contribution of the presented work is the design and implementation of a dynamic user-viewpoint tracking scheme in which mobile users’ spatial context is defined not only by their position (i.e., location), but also by their three-dimensional head orientation (i.e., line of sight). This allows the identification of objects and artifacts visible in a mobile user’s field of view with much higher accuracy than was possible by tracking position alone. For outdoor applications, a georeferencing based algorithm has been developed using the Global Positioning System (GPS) and magnetic orientation tracking devices [5] to track a user’s dynamic viewpoint. For indoor applications, this study explored the applicability of wireless technologies, in particular Indoor GPS, for dynamic user position tracking in situations where GPS is unavailable. The objectives of this paper are to describe the details of the three-stage-algorithm that has been designed and implemented, and to demonstrate the extent to which positioning technologies such as GPS and Indoor GPS can be used together with high-precision orientation trackers to accurately interpret the fully-qualified spatial context of a mobile user in challenging environments such as those found on construction sites. The obtained results highlight the potential of using location-aware technologies for rapidly identifying and retrieving contextual information in engineering applications.     

Secure multiple group ownership transfer protocol for mobile RFID

With the combination of mobile devices and readers in recent years, mobile Radio Frequency Identification (RFID) systems have been widely deployed in mobile identification. E-commerce, for instance, has applied many of mobile RFID’s deriving services, one of which is the transfer of a tagged item’s ownership in supply chains. However, current tag ownership transfer protocols can only transfer one tag at a time. For example, Yang et al.’s Secure Ownership Transfer Protocol is designed for low-cost lightweight RFID tags but it can only do one tag a time. For this reason, we propose a secure RFID protocol for group ownership transfer. We can transfer group(s) of tags’ ownership in one attempt. Since the two supplicants involved in ownership transfer are usually under different servers’ authorities, our protocol is designed to allow authority-crossing ownership transfer in a mobile RFID environment. Besides, it is able to assign its transfer targets and to secure against most RFID attacks.     

基于RFID的汽车零件运输跟踪系统设计

给出了一种基于RFID/GPRS的汽车零件运输跟踪系统的设计和实现。系统由总控中心、车载终端、客户终端、GPRS无线网及互联网等四部分组成。车载终端向总控中心发送的汽车零件RFID编码及所在的地理位置信息由总控中心处理。用户可用手机、电脑等客户终端设备,通过互联网与总控中心的服务器连接,输入RFID编号,即可查询到零件所在地理位置。由于系统使用了RFID和GPRS无线通信技术,具有较强的实时性,能够实现汽车零件在运输过程中的在线全程跟踪。