RFID embedded in supply chain

In its simplest form, radio frequency identification is a method to track what is inside a case, pallet or shipping container full of goods. But the evolving technology is more than a replacement for bar codes.

RFID eventually will reach every step of the supply chain and even be an integral part of other tasks, such as tamper protection and quality control, said David Stephens, senior vice president of the public sector for Savi Technology of Sunnyvale, Calif.

With mandates for RFID use being implemented by the Defense Department as well as companies such as Wal-Mart, contractors would do well to be knowledgeable about the increasingly more sophisticated technology.

Pentagon officials turned to RFID around 1992 during the Persian Gulf War to help the services determine the contents of supply containers and to provide end-to-end visibility of the supply chain, said Stephens, whose company provides RFID networks to the Defense Department as well as to commercial companies.

Since then, the Pentagon has expanded its use of RFID, but achieving complete visibility of the supply chain is still a work in progress.

"The challenges they're facing today is what they call the last mile," Stephens said. "It's essentially when supplies get to a distribution point and are disaggregated out to the users. It is at that point they lose visibility into that piece of the supply chain."

To address that, Savi has been working on what the company calls nested visibility, or the ability to see the supply chain from end to end.

An integral part of achieving that visibility will be using both active and passive RFID tags. Active tags have a battery, can be read from 300 feet away and hold more data than a passive tag. Passive tags generally have a three-foot to 10-foot range and hold less data, but also cost less.

A combination of the two, along with other software, hardware and technology, likely will be the way to achieve end-to-end visibility.

"If you look at what goes on in a supply chain, lots of things are happening: An item is put into a carton, a carton is put on a pallet, pallets go into containers which finally get put on some type of vehicle," Stephens said. Then the process happens in reverse at the destination.

"What you want to do is apply the technology that fits the application," he said. "For example, at the carton level it makes a lot of sense to use passive RFID, because of the lower cost."

On a pallet full of a single type of item, a passive tag would be appropriate. However, a pallet that is going to be taken apart and restocked several times in the supply chain might need an active tag, so the data can be rewritten every time the pallet is altered.

A truck-sized shipping container likely would get an active tag to get the reading range and ability to store the shipping manifest. The ability to store lots of data on a tag is important in a combat situation, for example, where connection to a network might be impossible.

"That's the concept behind nested visibility ? not only being able to track the container, but all the contents within the container down to a reasonable level," Stephens said.

Another technology on which Savi is working is battery-assisted passive RFID tags. The battery assistance adds sensors to passive tags to monitor conditions such as temperature and shock.

The technology was tested in shipping of combat rations, said Kathy Evangelos, program integrator at the Defense Department combat feeding program. The program examined the tracking capabilities of an RFID system along with those of temperatures sensors.

"Food is a very temperature-sensitive commodity," Evangelos said. The Pentagon tested the potential for sensor technology by creating a metric that determined the condition of rations from a temperature reading captured by the tags.

"It worked very well," she said. "It was cited as the definitive proof of principles."

Food rations will be among the first four commodities the Defense Department tracks at the case level using passive RFID. By 2007, nearly all goods are scheduled to have RFID tags, Evangelos said.

Standards established under the electronic product code has been a major factor in the maturation of RFID technology, said Lani Fritts, Savi's vice president of business development. The evolution is especially apparent on the hardware side. Until recently, separate readers were needed for passive and active tags.

"It's a little more complex having a passive reader board and an active reader board in the same reader or handheld," Fritts said.

Eventually, collecting data on inventory flowing through a supply chain will likely become fully automated, Fritts said.

Stephens expects an increased demand for RFID networks to be integrated with satellite and GPS transponders to further extend the range of visibility.