Data processing: financial – business practice – management – or co – Automated electrical financial or business practice or... – Inventory management
Reexamination Certificate
1999-12-16
2002-12-17
Bartuska, F. J. (Department: 2167)
Data processing: financial, business practice, management, or co
Automated electrical financial or business practice or...
Inventory management
C340S010100
Reexamination Certificate
active
06496806
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to tracking systems, and, more particularly, relates to a method and system for accurately tracking items that are moved, handled or processed in clusters, such as boxes, bags, containers and pallets, as well as other suitable means.
BACKGROUND OF THE INVENTION
Tracking systems are used in a wide variety of contexts to provide many different types of information. This information generally regards the location and availability of items being tracked. More specifically, this information includes, but is not limited to, information regarding (1) items received for purchase order reconciliation and accounts payable release purposes; (2) movement of items, storage of items or simply finding items within a facility for inventory control purposes; (3) monitoring the processing of items to ensure that each item has gone through the proper stages of processing; and (4) shipping of items to ensure order correctness and to trigger billing. This kind of information is required in warehouses, distribution centers, manufacturing facilities, service depots, postal sorting facilities, airports, retail and wholesale stores, as well as in any facility or network of facilities, such as a trucking system, which must accurately handle some volume of items.
For example, in a warehouse it is important to keep track of what items are in the warehouse, as well as where items are located within the warehouse. A tracking system in a warehouse should preferably provide information regarding where particularly items are stored in the warehouse and how many are stored in the warehouse, as well as information regarding when items are received into the warehouse and when they leave the warehouse.
Different systems have been devised for keeping track of items. This information may, for example, be recorded manually. Alternatively, each item being tracked may be marked with a bar code. In either case, the data must be entered into a central database in order to be useful in tracking items. Bar code scanning automates the entry of data into the central database. Whether a bar code or manual system is used, warehouse personnel must have a clear line of sight to the label of each item in order to either enter the item information manually or to scan the item information into the system using a bar code, and each warehouse worker must also read the label's one at a time. In many cases, packaging of items in boxes, crates, bags or other containers may make this operation very operator-intensive and inaccurate.
Radio frequency identification systems provide a number of advantages over other identification systems, such as manual or bar code systems. In radio frequency identification systems, information for each item is automatically gathered—warehouse personnel are not required to enter this information. In addition, reading distances can be longer, the tags can be hidden for security reasons, multiple tags can be read simultaneously, and, in the case of read/write tags, information can be stored on the tags, such as the purchase order number or the destination of the item. The foregoing are just some of the advantages of RFID tags.
A typical radio frequency identification system consists of transponders or tags, and an interrogator or reader (or multiple interrogators). The tag may be a single integrated circuit chip bonded to a flat, printed antenna, or could be a complex circuit including a battery and sensors for sensing temperature, position, orientation or other characteristic. RFID tags may be attached to items in many different ways, including being bolted to the item or simply glued to the inside of existing packaging or labeling. RFID tags may be encoded with user-defined data at the time of use, pre-coded with a numbering system at the time of tag manufacturing, or a combination of both approaches may be used.
For a number of reasons, it is preferable to use tags that do not require batteries—such tags are commonly referred to as passive tags and typically receive whatever power they require from an external power source. Passive tags are typically less expensive, require less maintenance, and have extended operating environmental ranges.
In the case of a passive tag, the interrogator will first activate the tag by generating an electromagnetic field of a given frequency. Such an electromagnetic field can be generated, for example, by supplying an alternating electrical current at a given frequency to a coil for low frequency near field systems—commonly called inductively coupled systems—or to an RF antenna for far field higher frequency systems.
The tag includes an antenna—which could be dipole for far field systems or a coil for inductive systems—tuned to the frequency of the electromagnetic field generated by the interrogator. The electrical current thus generated is used to power the tag. Data is generally sent to the tag by modulating the interrogator-generated electromagnetic field, which is commonly called the exciter or illuminating field. The tag can send data back to the interrogator either by transmitting with its own transmitter at a separate frequency from the illuminating field using the antenna, or by modulating the illuminating field by changing the loading of the tag's antenna in what is commonly called a back scatter system. Then, either the new electromagnetic field caused by the tag, or the disturbances in the interrogator's illuminating field caused by the tag's back scatter system, is detected by the interrogator. The data from the tag is then decoded, enabling the tag and the item to which the tag is attached to be identified, and, where the tag is a read/write tag, enabling new or incremental data to be written to the tag.
In a typical RFID tagging application, items to be tracked are tagged and gates with interrogators are installed at various key points in the facility that are significant in the tracking of item. For example, in warehouses, interrogator gates are typically installed at shipping docks in order to read the tags of items before they are loaded onto trucks. This system, however, can lead to many problems.
First, many gates or interrogators must be installed for this system. A typical distribution centre type installation might have more than 30 loading docks, each requiring a separate gate with interrogator. A typical manufacturing or sorting plant type installation might have a huge number of internal checkpoints requiring gates with interrogators in order to track the items and the processing that is applied to each item. Interrogators are very expensive. Thus, an application that requires a lot of interrogators is very expensive.
Second, interrogator gates restrict the freedom of movement of forklifts and people, as well as reducing the floor space available to receive items. This is particularly, a problem as gates are likely to be concentrated around the dock doors where space is at a premium—areas adjacent to the dock doors are frequently used as staging areas for temporary storage of items that are being moved onto trucks. The gate spacing and dimensions required to read the tags at the distance, speed, orientation and quantity that items are expected to go through the gate may also greatly restrict movements of the items. This tends to slow down operation and reduce read accuracy, and also makes it likely that the gates and the interrogators will sustain damage.
Typically, a large number of items are loaded on or off a truck or are moved through a facility at a time. For example, it is not uncommon to have 500 tagged items in a bag or box, or on a pallet, being passed through an interrogation gate at any one time. In an anti-collision RFID system, both the interrogator and the tags are specially designed to enable the interrogator to read multiple tags concurrently. In non-collision RFID systems, by way of contrast, only one tag can be in a field at a time in order to ensure a good read. This requirement of anti-collision RFID systems, that the interrogator and tags be desi
Davidson William E.
Horwitz Clifford A.
Bartuska F. J.
Samsys Technologies Inc.
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