Radio Frequency Identification (RFID) was born in the early years of World War II as a form of airplane identification. Allied aircraft were equipped with a transponder that returned an identification code when triggered by a radar signal. Despite this early start date, it was still several decades before RFID as implemented today came into common applications.
Perhaps the first commercial application familiar to most people is the electronic article surveillance (EAS) system used in department stores to reduce the theft of garments. These are simple one bit RFID systems that are attached to the item to be protected. They sound an alarm if an article is removed from the store without being paid for. When an article is purchased, the clerk removes the EAS tag, thus allowing the article to pass through the exit without triggering the alarm. Modern systems still have such a device, but now the clerk simply scans the tag over an electronic field, turning the tag off.
RFID systems consist of readers and tags. The reader radiates a signal that is responded to by the tag. The response may be as simple as a pre-recorded serial number in the tag or as complex as a set of data that has been recorded during the operation of the unit that is tagged. For example, the data could be that from a vehicle and include an odometer reading, fuel level, oil pressure, and other items of interest to the operator.
Readers may operate in one of a number of frequencies ranging from 125 KHz to 5.8 GHz. Tags may be classed as passive or active, read only or read-write, and with or without batteries. The range and speed at which a tag may be read will vary according to the frequency, power, and the number of bits of intelligence being passed. As a result, access control badges will typically have a read range of a few inches, while a toll road application will need to have a read range of 100 feet, or more, and at highway speeds.
RFID of Yesterday
The first patent for RFID systems was issued in 1973 to Mario Cardullo. Today there are more than 60 patents on RFID systems. While EAS systems developed by Sensormatic and Checkpoint were the leading applications of RFID, a number of companies worldwide that began to apply the technology to animal tracking of farm animals such as hogs, cattle, and sheep. The tracking permitted the farmers to more easily track specific animal growth, thus providing better feed control and costs.
Today there are many RFID applications, including electronic toll collection, weigh station bypass, railcar tracking, airport curb space control, personnel access control, inventory management, process control, special event control, livestock tracking, and product identification and protection. This is not an exhaustive list.
Product identification and protection may be viewed as similar to the EAS system, but extended to include inventory control and other warehouse tracking applications as trucks are loaded and unloaded. Livestock tracking using RFID has expanded to include identification of race horses, high value animals (pure breed, specialty animals, etc.), and even pets are common applications.
There are a number of applications today that would be classed as event control. For example, in a cross-country race, or marathon, the participants may wear ankle bracelets that contain RFID tags, allowing easy identification of winners. Another application that may not be recognized as RFID is tags embedded into car keys that inhibit the car starting unless the correct key code is recognized. RFID is found in a number of related applications that would have originally been classed as personnel access control. Originally used to allow ingress to certain areas and time control, the system has expanded to track patients in hospitals and even service personnel for quick identification and alerts.
Perhaps one of the greatest growth industries for RFID applications has been the transportation industry. Airports have shown interest in controlling curb space use through the use of tagged commercial vehicles and tagged automobiles within their parking facilities. The rail industry has gone to the extent of tagging all domestic rail assets in an effort to help in inventory control where railcars move from company to company.
One of the largest applications for RFID today is the weigh-station bypass program first implemented in 1991 in six western states and British Columbia. The program was a combination of automatic vehicle identification (AVI), weigh-in-motion (WIM), automatic vehicle classification (AVC), and integrated networks and data bases. The intent of the program was to provide a method of automatically identifying commercial vehicles as they approached a weigh-station, weighing them, checking their data base credentials (safety records, insurance, and other data), and being able to signal the vehicle with a green light to enable the vehicle to bypass the station. The rationale behind the program was to allow the station to focus on those carriers who did not have good records. There are a large number of states currently implementing this program.
Another application that has found great success is in electronic toll roads. While first started in small installations in San Diego, New Orleans, and Dallas for both bridge crossing and toll roads, the application is now found commonly across the United States and Canada, and many other countries.
RFID has made major advances in a number of applications, but there are problems that continue to require answers, such as concern for privacy, common protocols, costs, and qualified solutions. The concerns for privacy arises in current applications such as toll ways and becomes even more vocal when the tagging of drivers licenses and passports are mentioned. The vision of "big brother" knowing your every move causes a vocal outcry against such technology.
The cost of RFID systems continues to decrease and is now commonly less than $1 per tag price. Many tags are reusable, being able to move from asset to asset. This cost reduction may continue to the point that tags will be found in the $.10 to $.25. When that happens, it will provide cost justification for many new applications. The limits of RFID and its application have been tapped with the low hanging fruit – but the tree of possible uses has many more opportunities to be harvested.