一种基于RFID的集装箱定位和识别新构架

g Containers Location and Identification Architecture in Multimodal TransportZhengwu YuanSino-Korea GIS Research Center, Chongqing Univ. of Posts & Telecom. 400-065, Chinayuanzw@Dongli HuangSino-Korea GIS Research Center, Chongqing Univ. of Posts & Telecom. 400-065, Chinayourdonnie@,AbstractIn this paper, a new integrated architecture is proposed through moving passive RFID and GPS equipment into shipping container to make the cargos and containermonitored and located even if the container is loaded, stored, hoisted and transported.New architecture can complete the function of not only passive RFID productsidentification but also active RFID container tracking of long distance. All kinds ofcustomhouses, checkpoints and container dock themselves even don’t need to buildRFID network to manage cargos and container, as all real-time information can beinquired through EPC network by authorized users. In addition, this architecture cancompletely solve collision problem and enhance the information security, automaticmanifest, adaptability of geographic area and anti-theft.Keywords: RFID, GPS Location, Container Tracking, EPCglobal Network1IntroductionRadio Frequency Identification (RFID) has recently drawn much attention in supply chain and is beginning to be used for ubiquitous object identification as a feasible technology that can improve logistic management, supply chain operation and asset tracking. In passive tags field, several major retailers such as Tesco, Metro Group and Wal-Mart have deployed passive RFID systems in some of their supply chains process. In active tags field, some companies, such as AXCESS and SAVI, have applied active tags in container tracking and identification.Some analysts estimate that there are currently more than 18-20 million shipping containers in use around the world. Therefore, containers location and identification have extensive market where RFID tagging has a future. Sophisticated harbors, like Singapore, are already equipped to handle RFID-tagged containers [1]. These RFID technologies attach an external active tag outside container for container identification and tracking.However, in actual application, existing active RFID container tracking often isn’t reliable due to the obstruction of other metal containers or vehicles. Collision problem and expensive active RFID system also affect the application of container tracking. In this architecture proposed, only passive RFID system is used and the long list of potential benefits, such as collision avoidance, real-time automatic manifest, geographic area adaptability, reduction theft and cost savings, will attract the attention of the entire supply chain industry. In addition, existing GPS container tracking can locate the position of container but can’t identify the cargos in container and ensure the safety of cargos.2Related workThe significant deployment of container tracking has been implemented with active RFID. As too much disadvantages (analysis in section IV) are arose, our solution will use passive RFID which generally is used for short distance identification. There are so many international companies, such as HP, IBM, SUN, SAP, ORACLE, OAT SYSTEM and so on, deploy their own RFID solution for short distance product identification based on EPCglobal Network which defined by the EPCglobal Consortium as an international standard.2.1EPCg lo ba l netwo rkThe EPCglobal Network is the Auto ID Center’s specification and specifies major aspects of operation of Networked RFID system. The EPCglobal Network Architecture can enable readers to identify and monitor RFID products and then, access crucial database to query cargos information through internet, such as a detailed product description; when and where it was made and shipped; when and where it was sold; and how it was used and maintained.The EPCglobal Network consists of several main components such as Object Naming Service (ONS), the EPC Information Services (EPCIS), Physical Markup Language (PML), EPC Discovery Services [2] and so on. These components will be introduced as following.EPC (The Electronic Product Code): EPC developed by the Uniform Code Council (UCC) is a set of coding schemes for RFID tags. RFID in combination with EPC can help computers automatically and uniquely identify everyday objects. The aim of the EPC is to provide a unique number to identify a specific object in the supply chain. The EPC in itself is meaningless unless it is matched with other data. The Networked RFID can prevent unauthorized users from translating EPC into specific product information behind firewalls, encoding and other security measures. Thus, even if the unauthorized users can receive the EPC using a reader, the information of EPC can’t be understood.Savant: Savant is developed by the Auto-ID Center to act as the central nervous system of The EPCglobal Network architecture to filter, aggregate and report RFID data prior to sending them to a requesting application. Savant ensures that only significant information and data packets are propagated to application and information systems, rather than original RFID data.ONS (Object Naming Service): In the EPCglobal Network, EPCglobal maintains the root the Object Name Service directory. But each company will have a server running its own ONS as the ONS need to handle so many requests. Like Domain Name Service, which registers and looks up the IP address for Web site, ONS will translate an EPC into a number of internet addresses and point computers to the internet databases where further information can be found [3].EPCIS (The EPC Information Service): The EPC Information Service provides a uniform capture and query interface to enable various clients to capture and exchange real time EPC data with trading partners through the Networked RFID [4]. As EPCIS is individual databases for companies, actual access to data is managed at the local level where each company itself implements security access control. EPCIS be used to connect the savant to EIS (Enterprise Information Systems) systems such as ERP (Enterprise Resource Planning), SCM (Supply Chain Management) and WMS (Warehouse Management Systems) as well as other applications that might want to use tag information.PML (Physical Markup Language): PML is a markup language based on XML (eXtensible Markup Language) for describing physical objects [5]. The goal of PML is to provide a commonEPC Discovery Services: The EPC Discovery Services are essentially a suite of services that enable users to find information related to a specific EPC and to request access to that data [6]. They simplify the data exchange and share data with different trading partners by offering a service that links individual EPCIS in the supply chain. The EPC Discovery Services provide a unified view of product data throughout the distributed supply chain and make it as easy to find data as it is to use an internet search engine. When an EPC tag is encoded and attached to a product, that data are transmitted to the manufacturer's EPCIS and EPC Discovery Service. If products get through different transport company, distributor or retailer, individual EPCIS is founded and interacts with the EPC Discovery Service throughout the life of supply chains.2.2G P S T ra ck i n gThe Global Positioning System (GPS) is a satellite-based navigation system using 24 satellites in space and transmitters and receivers on earth. GPS module is a receiving device that must grasps the signal of at least three satellites to calculate a precise 2D position (latitude and longitude) and sends position of the container, at regular intervals, to savant. With four or more satellites in view, the GPS Module can determine the container's 3D position (latitude, longitude and altitude) [7]. GPS system can calculate speed, track and so on. EIS can use these data to estimate the distance and time to destination.Some companies, such as NovAtel, and SAVOR have applied GPS in container tracking. Traditional GPS tracking have about 10 meters error. To enhance the accuracy of the computed position, RTK (Real Time Kinematic) and DGPS (Differential GPS) technology are adopted in GPS container tracking, although they need long recovery time (Figure 1).Figure 1. Different GPS technologySAVCOR deploys GPS container tracking with DGPS technology owing to the satisfying position error and acceptable recovery time. To compensate for the loss of satellite lock in GPS shadow areas close to the quayside cranes, SAVCOR utilizes two independent, redundant DGPS receivers and antennas on opposite sides of the container. In SAVACOR system, Low-Earth Orbit (LEO) satellites are most likely to be used for sending short data messages because their cost is cheap relative to traditional satellite services.3 A novel RFID-based shipping containers location andidentification architectureAlthough there are so many RFID solutions for supply chains nowadays in passive RFID field, these solutions are designed either as handheld RFID readers for mobile workers in warehouses and on factory floors or as fixed reader equipped in the doorway or warehouse. When cargos are loaded in container, the Networked RFID can’t monitor the cargos any more as the products tagged aren’t within the range of a reader.3.1La y e r s of n ov e l a r ch it e c t u r eTo support location-based service and solve the accurate consignments, no collision, information security, automatic manifest and advanced anti-theft problem, novel architecture is defined in figure 2.Figure 2. The layers of new architectureThe novel architecture framework is abstracted into following four layers.1) Data Collection LayerThe foundation layer consists of the actual hardware and software of the RFID and GPS devices which are equipped in container to complete the data collection function. These devices can be any number of RFID tags, readers and location devices. Each reader continuously reads RFID tags and sends the data which combined with GPS data to the RFID Network Filter Layer for further processing. Tag read speed is approximately up to 1500 tags per second to C1G2 tag type. Data collection layer is crucial in entire framework, because it influences efficiency of processing. As EPC is combined with position information in lowermost layer, application layer don’t need to connect other positioning systems for supporting position service.RFID Network Filter Layer is primarily responsible for filtering data from RFID tags with a unique EPC which describes a tagged object's manufacturer, product type, and serial number. This layer provides an interface that enables RFID readers and GPS module to be connected to the EPC Network and integrate RFID data with position attribute. In this layer, RFID data are integrated and filtered as well as GPS data are integrated into each EPC and transferred to up-layer directly as the GPS data have to be processed farther depending on internet resource. The EPC number of shipping container also is processed like EPC number of product.3) RFID Network Process LayerRFID Network Process Layer is used by Business Applications Layer to transform EPC and WGS 84 (World Geodetic System of 1984) coordinates into detailed product description and geography location, such as what product the matching RFID tag denote; when and where this specific product was made and shipped, where it is at present and how it was used and maintained.4)Business Application LayerThe Business Application Layer is the top layer in our Architecture Framework and performs common application services for business application processes. It includes manufacture planning and merchandise allocation, store operations, sales marketing, container management and identification and so on. This layer is used to process matching tag data and information for ERP, WMS, SCM and other existing information systems that might use EPC tag information as well as position service.Working in coordination, the layers defined above provide the ability to capture and trace cargos movement in real time in the Networked RFID. As RFID readers are placed in container, they can read each tagged object and send the EPC number, the time and the location of container to the Networked RFID. Once the information is captured, the Networked RFID can use internet technology to create a platform for sharing that information with authorized trading partners, retailers, checkpoint, customhouse and container dock. From there, actual access to data in the Networked RFID is managed at the local level by the EPCIS where the company itself designates who have access to its individual data, as shown in Figure 3.Figure 3. New architecture configurationThe process starts with a product or container affixed an RFID tag that includes a unique EPC number. Figure 4 shows an entire operation activity and includes several actors (Manufacture, Distributor, Retailer, Customhouse, Container Spot and Transport Company). All of the actor’s EPCIS are registered in the ONS and invariant EPC number is saved in tag. The entire operation activity consists of six basic steps.Step1: When products are produced, the EPC number of tag and relevant information of product are added to the Manufacturer's EPCIS.Step2: The information that product data can be found within the Manufacturer's EPCIS is sent to the EPC Discovery Services. The product data maybe consist of some items such as when the product is manufactured, how long the guarantee period is, how to use and maintain this product and so on.Step3: When the product leaves the manufacture and is handed over to transport company, its departure and arrival information are automatically registered with manufacturer and transport company’s EPCIS. Using this new solution proposed, the transporting information of cargos and container are sent to transport company’s EPCIS momentarily.Step4: The information that further transport data can be found within the transport company’s EPCIS is sent to the EPC Discovery Services.Step5: When the cargos get to distributor or retailer, the information is saved to distributor or retailer’s EPCIS.Step6: The information that sale or storage can be found within the distributor or retailer’s EPCIS is sent to the EPC Discovery Services.Query process: The EPC number in itself is meaningless, before it is translated into corresponding description. When a retailer or distributor wants to get product description through EPC number received from a reader of his own, it asks the ONS for the location of the Manufacturer's EPC Information Service and accesses the Manufacturer's data such as what the EPC number represents, when the product is manufactured, how to use and maintain and so on. When customhouse or container dock wants to know whom the container belong to, the current position of container and so on, it uses the EPC number of container received from transport company to ask ONS and the EPC Discovery Services and gets transport company’s EPCIS for further container information.Figure 4. New architecture active stepsThe new architecture framework allows fleet owners or driver to scan and identify the real-time positions of the cargos using mobile phones, notebook PCs and various mobile devices through a support chain platform consisting of Networked RFID, GPS tracking and GIS (Geographic Information System) service. When GIS detects a container approaching a foreseeable checkpoint and customhouse, networked RFID can automatically send EPC number of container, which read by on-board reader from a passive tag of container, to the checkpoint, container dock or customhouse through internet. The checkpoint, customhouse and container dock can use the EPC number to identify and locate the container through EPC network’s translation. In transport company’s EPCIS, the EPC number of container is associated with container information such as whom the container belong to, what the manifest contains, where the current position is and so on.Some materials such as water and metal absorb RF signals more readily than others in UFH frequency which is used by supply chain passive tags. Because of these problems, read rates of RFID tags are no more than 98% in real application. In this new architecture, some methods are used to find a solution to these problems. Firstly, multi-readers can be used in different position of container and loop checking processes are implemented to improve the read rates. Multi-readers information will be integrated by savant and delete the same items to improve read rates [8]. In addition, threshold volume can be set. Only when the missing amounts of cargos reach to the threshold value, the monitoring system alarm.When cargos are loaded in container (fig. 5), the Networked RFID combining GPS tracking can monitor the cargos and container to provide cargos information and container position information for supply chain management.Figure 5. Container equipped with new solutionIn this section, some of the shortcomings of the existing system are discussed and the enhancements made in this paper are described.Two sets of RFID system: To drive down the cost of RFID tags and attach RFID tag to each retail product, retail products have to use passive tags which are read by passive reader. To increase transmitting distance and support container tracking, containers have to use active tags which are read by active reader. In this solution, only passive RFID system is used.Collision problem and Security problem: The use of the shared RF medium for communication with tags incurs the problem of readers potentially interfering with one another’s operation. Collision may be due to either frequency interference or tag interference. Frequency interference occurs when physically close readers communicate at the same time on the same frequency. Tag interference occurs when neighboring readers attempt to communicate with the same tag at the same time [9]. Many variants of the collision problem for RFID have been studied, and many anti-collision algorithms have been proposed. However, in actual operation, anti-collision algorithms always create inefficient read speed and even incur read failing. In this solution, as the electromagnetic wave of UHF (Ultra High Frequency) can’t penetrate the metal container [10], the RFID reader will be divided into independent section by metal container. Therefore, collision problem is avoided. In addition, as a result of radio shield, metal container muffles the cargos and prevents any user from accessing tags outside.Automatic manifest and identification: One of the constant challenges in today's supply chains is maintaining the accuracy of manifest and identifying the vehicle. Often the shipment manifest contains the wrong quantities of product, or even the wrong product type. As existing RFID container tracking encoded manifest data in an active RFID tag in advance, shipment manifest maybe is different from the actual cargos because of theft, worker’s mistake and so on. Especially in customhouse, the difference between actual cargos and manifest will make serious trouble. In this novel solution, when GIS (Geographic Information System) detects a container is getting through a foreseeable checkpoint or customhouse, Networked RFID can automatically send electronic manifest and identification of vehicle to the surveyor through internet behind firewalls, encoding and other security measures.Geographic area change: Many applications, such as container tracking and automatic product detection in supply chain management, require RFID readers to be able to read tags anywhere within a large geographic area. Owing to the limited range inherent in the reader-to-tag communication, readers must be deployed in high densities over the entire area. If the geographic area take place a change, the new RFID reader has to be equipped. In this proposed solutions, on-board RFID reader can read product tag and container tag, then send EPC number to EPC network. Therefore, container spot don’t need to deploy other RFID readers.Theft: Container theft is a very serious and growing problem worldwide, as container move across the country and the world. For instance, in the United States it is estimated that the annual cost of cargo theft and pilferage varies from US$ 3 to 10 billion a year. Existing traditional technology uses electronic seal (e-seal) for cargos safety [11]. The e-seal is composed of an active RFID tag and a mechanism that can detect whether the door of container has been opened without authorization to guarantee the integrity of cargo. But if theft takes place through drilling a hole in container, all safety technologies are so weak. As RFID tags can be attached on secret part of cargos even inside cargos, Networked RFID can find the cargos are moved out the range of a reader, even if the thief steals cargos through drilling a hole in container. In addition, when thousands of products are tagged, it is incredible to tear all tags and steal cargosIn this paper, a new solution that integrates passive RFID and GPS tracking to enhance supply chain visibility in straddle carrier is proposed. Improved performance such as real-time location service, no collision, information security, automatic manifest and identification, adaptability of geographic area and anti-theft, will make this solution have some contributions for future container tracking and identification.6 AcknowledgmentsThis work was supported by the research project of education science and technology in Chongqing (No.J2006-16), the emphases project of Ministry of Education of the People’s Republic of China (No. 207097) and research project of Chongqing Natural Science Foundation. 7References[1]Emily Sopensky “The Sun, The World and RFID” December 2005 /Foreign Service Journal[2]Mark Harrison, Duncan McFarlane, Ajith Kumar Parlikad, and Chien Yaw Wong, “Information management in theproduct lifecycle-The role of Networked RFID” AUTOIDLABS-WP-BIZAPPS-014[3]Inseop Kim, Byunggil Lee, and Howon Kim, “Privacy-Friendly Mobile RFID Reader Protocol Design based ontrusted Agent and PKI” 1-4244-0216-6/06 2006 IEEE[4] A.G. 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Sarma "Colorwave: An Anticollision Algorithm for the ReaderCollision Problem" 0-7803-7802-4/03- 2003 IEEE[10]Gaynor Backhouse, JISC TechWatch "RFID: Frequency, standards, adoption and innovation" JISC Technology andStandards Watch, May 2006[11]Le-Pong Chin,Chia-Lin Wu "The Role Of Electronic Container Seal (E-Seal) With RFID Technology IntheContainer Security Initiatives" 0-7695-2189-4/04-2004 IEEEAuthor Brief Introduction：Zhengwu Yuan was born in China in 1968. He received Ph.D degree in Central South University, China in 2003. He is now an Associate Professor with Institutes of Computer Science and Technology at Chongqing University of Posts and Telecommunications His research interests include location based services, spatial information, virtual reality and GIS.Dongli Huang was born in China in 1975. He is working towards his M.S degree in Chongqing University of Posts and Telecommunications. His research interests are in Networked RFID and RFID Location.。