The other side of RFID

When it comes to radio frequency identification technology, the government turns to the Defense Department for lessons learned. DOD has finalized changes to its acquisition regulations to require its vast network of suppliers to place tiny, passive RFID tags on the goods it ships to Defense customers. According to Alan Estevez, the assistant deputy undersecretary of Defense responsible for supply chain automation, many suppliers had begun to do so voluntarily.

But DOD has a long history with RFID, including successful use of active RFID tags'those that actively transmit data'as far back as the first Gulf War. Even now, pockets of task-specific RFID usage are in the early stages at many Defense outposts, providing a look at what other agencies might learn and expect if they should adopt the emerging technology.

The Warner Robins Air Logistics Center has replaced a system of manual inventories with an RFID system to track pricey gyroscopes moving through the repair facility at the Robins Air Force Base in Georgia. The system of active RFID tags, readers and management software has reduced an inventory process that used to take an entire day to only 10 minutes, said Cynthia Gunter, the center's Automated ID Technology program manager.

'Now, they bring up a screen and, voila! They know where [the gyroscopes are],' Gunter said.
Not only is the information available quickly, it is available to everyone who needs it. 'You're sharing this business knowledge so everybody knows where it is,' she said.

The system from RF Code Inc. of Mesa, Ariz., also helped create IT fans among the wrench-turners who do the actual maintenance work, said Margaret Padgett, the IT division's business and resources development chief.

'They're always skeptical' of new systems, said Padgett, who helped spearhead the RFID program. Major IT projects typically give maintenance personnel more systems to monitor, 'and they were doing less wrench-turning. This was the first time IT came in to help without taking time away from the mechanics.'

Active over passive

DOD's plans to use passive RFID technology to manage its supply chain has gotten a lot of publicity in the last year, but the three Air Logistics Centers in Georgia, Oklahoma City and Ogden, Utah, have been using active RFID for a while, with the gyroscope system coming online in the last year. Active RFID typically is more expensive than the passive tags. But passive tags can only tell you where something has been. Active tags tell you where something is at a certain moment.

'Passive tag technology is not a business tool for real-time visibility,' Gunter said. 'This is a great business fit for active technology.'

Still, cautions Nissim Ozer, chief technology office of RF Code, 'there is no one technology that will meet all of your needs.'

For keeping track of large numbers of individual items and people, bar codes and readers are used everywhere from retail checkout counters to airline boarding gates. Passive RFID is good for tracking high-volume commodities through a chain, and active RFID is good for keeping a constant eye on more expensive items.

The Warner Robins Air Logistics Center is where the Air Force repairs, upgrades and refurbishes gyroscopes used on aircraft. The devices are shipped to the repair facility by the Defense Logistics Agency, which uses the Automated Materiel Tracking System to keep track of items in transit up to the point of delivery. But AMTS ends at the loading dock at Warner Robins, right after the Air Force signs for the gyroscopes.

'When you get to the shop, AMTS stops,' Gunter said, and a manual system of control numbers and inventory used to take over.

When the Air Force Materiel Command was looking for pilot programs in which IT could improve efficiency, the Air Logistics Centers became test beds. The gyroscope repair facility at Warner Robins volunteered to try out a system. A demonstration of the RFID technology was set up in early 2003, and after a prototype program went successfully, a contract was awarded in July 2004.

How it works

The center selected a system from RF Code for the implementation. It consisted of Mantis tags and readers and the Tavis Data Management Platform software, both from RF Code. The tags are 2.4 by 1.2 inches and less than half an inch thick. Each tag has an ID signal that identifies it to the reader, and can also transmit additional data such as temperature and movement. The tags are configured during manufacture to transmit regularly anywhere from about seven times a second to once every several seconds.

The reader can pick up the signal at a range of 300 to 1,500 feet, depending on the antenna used and the environment. Fixed readers, which are configured and connected to a network much like a wireless access point, provide continuous monitoring of an area. Readers also come as PC card-based add-ons that can be installed in handheld devices for tracking down individual tags.

Each reader can pick up and recognize up to 150 signals per second, and the number of tags one reader can support depends on how freque ntly each tag is set to transmit.

In a real-world application, setting the tags at the fastest speed'once every 0.15 seconds'is not practical, RF Code's Ozer said. Practical intervals start at once every second, and the sweet spot is once every 12 seconds. This is the frequency used at Warner Robins. When motion is detected, they transmit every second to provide a record of their movement.

Data gathered by the readers is managed and integrated with business applications through the Tavis software. Tavis works with any kind of auto-ID system, including bar codes, passive RFID, Global Positioning System and cellular devices, as well as the Mantis system. It supports Linux, Windows CE and Windows desktop operating systems.

At Warner Robins, Tavis integrated with AMTS, which was supported at the center by Computer Sciences Corp.

'CSC knew AMTS, RF Code knew Tavis, so we got the two of them together and that started the integration,' Gunter said.

The integration in 2004 marked the transition from a prototype to a production system. The gyroscope work area is divided into 19 zones, with a reader in each zone. The center bought 500 tags, about 300 of which are in use at any given time.

As each gyro is received from DLA, it is assigned a control number and tag and is followed throughout the repair process. When the gyro leaves the shop, the tag is removed and put into a 'disassociation chamber' with its own reader. When the tag is read in that chamber, the system recognizes that control number as available for reuse on another gyro.

The system was originally used as a supply-side tool to keep track of the gyros, Gunter said. 'Then the maintenance side said, 'we can learn from this.' '

With some tweaks to Tavis and AMTS, it became a desktop workflow tool that can show the status of each job at any time, as well as the location. Reports can be generated based on a variety of criteria so that bottlenecks can be found and the inventory and flow of spare and replacement parts improved.

Other divisions at the Warner Robins Air Logistics Center are turning to the gyro shop for advice on implementing RFID. The Precision Measurement Equipment Lab, which calibrates sensitive devices for the Air Force, is using the same network of 19 readers to track its own equipment.

'The plan is for this to grow even more,' Gunter said. 'Come back to me in a year, and we'll have another six projects.'

About the Author

William Jackson is a Maryland-based freelance writer.


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