RFID Technology

Almost every product we buy has a bar code printed on in. A bar code is nothing but machine-readable parallel bars that store binary codes revealing information about the product. But the days of barcode are numbered. The technology called radio frequency identification (RFID) is catching on.

Every person has got his identity either by his name or by his characteristics, every thing has got his own identity either by its name or by its quality. So in this new wireless era, a specified frequency has become an identity of a person or an object. This is possible by the technology, RFID.

RFID means providing identity to any object. A typical RFID system will consist of a reader, a tag and some kind of data processing system to process the data. The reader transmits the RF waves to the tag. The tag hears the RF wave. The information carried by the RF wave can also be given to the host PC or even a complete LAN.

RFID technique as a dominant technology concerning electronic data collection and transmission. The system uses radio frequencies that is, electromagnetic waves in the range 10-30 KHz(VLF) to 30-300 GHz(UHF).A typical application may use 50 KHz-2.5GHz.

The basic RFID system consists of the following blocks :

TAG: A tag is the device, which is attached with the item, which is to be tracked or loaded. The tag consists of electronic chip used to store data that can be broadcast via RF waves to the reader. The main function of the tag is to respond to a transmitted request from the reader for the data stored within the tag.

There are two types of the tags, active tags which include a battery and passive ones, which is not. Passive tag has infinite lifetime, are smaller and lighter than active tags, and less expensive., On the other hand, they require more power from the reader and they have a shorter read range.

READER: The reader directs the RF transceiver to transmit RF signals, receives the encoded signal from the tag through the RF transceiver, decodes the tag’s identification, and transmits the identification with any other data from the tag to the host computer.

THE CONTROL SECTION: The information obtained by the reader from the tag can be passed to the host PC or the LAN.

RFID operates in several bands. The generic frequencies for RFID are:
125-134 kHz
13.56 MHz
400-930 MHz
2.45 GHz
5.8 GHZ

Each of the frequency bands have advantages and disadvantages for operation. The lower frequencies 125-134 kHz and 13.56 MHz work much better near water or humans.

Read range is the maximum possible communication distance between tag and reader for proper functioning. It depends upon operating frequency sensitivity of the receiver, antenna orientation. The maximum distances between tag and the reader is not only a function of the power output of the reader, but also of the power available within the tag to respond, as well as of various environmental conditions, the kind of antenna used, and the frequencies at which the system operates.

This is the brief idea of RFID and its basics concepts. RFID finds its application in a wide range of real time systems such as electronic toll collection, asset management, animal tagging, item management, access control, airport security system, automatic vehicle location, etc.

AUTOMATIC VEHICLE LOCATION USING RFID

The traffic management system uses RFID technology for providing accurate information on arrival, departure etc which forms the crucial information of the system. Accurate real-time data for traffic management system are provided by automatic vehicle location. To comply with basic technical requirements of traffic light priority and passenger information systems has adapted and developed passive low frequency RFID technology for AVL. The AVL system is characterized by very accurate positioning of vehicles (+/-1cm at low speeds 30km/hr and 1/2m high speeds up to 300km/hr.

AVL system consists of all basic elements of RFID system. The tag either attached to the vehicle, or embedded in the roads, the readers situated on the way in the infrastructure on the vehicle, and the host computer in the control room.

In this system, locating and tracking the vehicle is done by position tag embedded in the road surface, when a vehicle passes through the position tag in the road the ID codes stored in the Tag memory is transmitted the reader on the bus to a computer at a control room via radio link. All tag ID codes are stored in the data base of he computer and by the ID codes are stored in a database in the computer and by comparing the ID codes of the passed tag to the ID code in the database using radio range algorithm stored in the computer, thus it is possible to pin point the location of the vehicle accurately. Between any two tags located on the route followed by the vehicle, position data is sensed from the vehicle odometer to latest tag location. Position data derived when passing the position tag can be used to calibrate the odometer and increase the position accuracy. Hence indirectly vehicle speed data can also be determined.

Along with the vehicle position and speed any other information from any other sensor on the vehicle like ticketing machine driver ID card reader, driver display, fuel indication can also be transferred to the computer situated in the control section. In the control room the data received from the reader is processed using various algorithm. This processing involves, finding the position and speed of vehicle, finding the position and speed of the vehicle etc. Based on the processing relevant actions are taken such as, displaying arrival and departure time of vehicle, locating the position of he vehicle on the infrastructure map, catching and catching an illegal vehicle from entering a particular area.

In this way radio waves become the identity of the vehicle (with an attached tag), which helps in tracking them.

As mentioned above, this technology finds so many applications one of them mentioned i.e. AVL. Similarly Browsing shoppers inside a store for retail insights through an RFID tracking system. With tag readers placed on the shelves of bookstores, the system allows booksellers, to gain such information as the range of books a shopper has browsed, the number of times a particular title was picked up, and even the length of time spent flipping through each book.

Radio frequency identification is providing its potential contribution in the field of automation with wireless communication, as is has successfully overcome the disadvantages and proved better than the exiting similar techniques. Also RFID is one among those technologies, finding applications in a very broad spectrum.