Dec 07, 2006Inventory used to be a major chore for personnel at the Extremely High Frequency Satellite Communications (EHF SATCOM) branch of the Space and Naval Warfare Systems Center (SPAWAR) in San Diego, Calif.
Under U.S. Department of Defense (DOD) regulations, physical inventory of all goods with serial numbers is required annually at SPAWAR centers. For the EHF SATCOM branch, that means counting more than 4,000 serialized configuration-control components. The facility stores these circuit cards, which can be built into subassemblies used in satellite communication devices, to serve the needs of DOD depots around the world.
Serco, a business-services firm based in the United Kingdom, counts SPAWAR's EHF SATCOM branch among its clients. Barry Jones, Serco's senior logistics consultant, had planned to improve the branch's manual inventory-taking process by adding 2-D bar codes to each serialized item, then using handheld scanners to read them. The system would send the unique ID collected from each bar code directly to the inventory software used by the branch, saving personnel from having to hand-count and enter the IDs into a spreadsheet.
This spring, however, before Jones implemented the bar-code tracking system for the branch, he learned about how RFID technology can be used for inventory applications. Intrigued, he took an educational course offered by RFID hardware provider Alien Technology. Throughout June and July, Jones led a team at the EHF SATCOM branch, evaluating the capabilities of a system in which Alien's Squiggle UHF Gen 2 passive tags could be attached to circuit cards and read using a handheld reader. The tag data, he says, would need to be filtered for duplicate reads and sent to the Catalog Ordering Logistic Tracking System (COLTS), the branch's existing inventory-management software, made by Avantix.
Jones and one of his Serco colleagues, John Bolton, worked with a third-party software consultant to write a program that generates a 96-bit unique identification number for each item. This unique ID, as well as a 2D bar code encoded with the serial number, is printed on an RFID smart label, and also encoded to the embedded Squiggle inlay. The 2D bar code acts as a backup to the RFID inlay. The team applies each label to a 4- by 2-inch piece of card stock attached by string to each inventory item.
Testing of the system took less than 90 days, says Jones. Since October the team has been addressing minor bugs found in the software layers. Once these are fixed, the branch will roll out the program on a permanent basis. Jones says it has tagged all 4,000 serialized items at the facility.
The circuit cards are stored in drawers held by large metal racks. Thus, personnel must remove each drawer from its rack before reading the handheld device. Attempts to read the tags while the drawers are in the racks have proven unsuccessful because the metal interferes with the RF signal transmitted by the reader. Jones says that having to remove the drawers adds a small amount of time to the inventory process, but that it's not significant. Under the manual system, conducting an inventory of 85 circuit cards took approximately two hours to complete. The use of passive RFID tags has cut that time to less than five minutes.
"Because the inventory is easier to take, [branch personnel] will do it more often, and the accuracy will likely increase," says Jones. He adds that the RFID system will also streamline the process of updating the locations of inventory items in the database.
Under the manual system, when personnel move inventoried parts to a new physical location within the facility, they must manually change the location in the inventory database for each item. "This isn't a big deal until you have to move 50 drawers of parts," says Jones. Now, they can change the location of multiple items by using a function written into the integration software IntelliTrack installed on the handhelds.
The software also keeps track of the time and date of each tag read, then imports this information to the COLTS database, which provides a record of when each inventory was taken.
The EHF SATCOM branch, Jones says, will likely begin tagging the cases and pallets of satellite equipment it sends to the DOD before the department requires it to support an RFID mandate for tracking shipments headed to its materiel depots. That is because attaching the tags may help the branch automate shipment tracking. Still, he points out, none of the DOD facilities the branch ships to are yet RFID-enabled. Therefore, EHF SATCOM may wait for those facilities to add RFID readers before it begins tagging shipments.
