The purpose of this project is to study the feasibility of replacing bar code technology with a next-generation system that does not require human interaction. A radio frequency identification (RFID) system is being developed for this application. A typical RFID system consists of three basic parts: the database (if a central database is used), the reader, and the transponder (Tag). Communication is required between the transponder and the reader and between the reader and a centralized database. Wireless technology is used for the transponder-to-reader communication. The reader-to-database communication uses a serial interface and/or network technology.

The RFID system technology is currently fragmented. There is no standardization at any level. At least eight carrier frequency bands are in use around the world, ranging from 100 kilohertz to 2.45 gigahertz. Many of the product lines are sold as complete systems and do not interface with others except at the database software level.

There are competing hardware and software products that can be used to create a system at virtually any level of commercial integration.

There are two main categories of Tags - active and passive. Active Tags have a battery power source, which limits their maximum life expectancy to about 6 years. The battery makes the Tag substantially larger and more expensive but gives the system a much longer read range. Passive Tags get their power from the reader's transmitted carrier frequency. The Tag captures the energy transmitted from the reader and uses it to transmit back to the reader. The power-level limitations of the reader's transmission limit the range. Compared to active Tags, passive Tags are inexpensive and small and have no defined life expectancy limits..

The method being developed for this project will track tagged property as it passes through portals at doorways. The portal will consist of a Tag reader with multiple antennas and several photocells and will detect the assets and the direction of movement. The portal reader will then transmit this information to a central database that will show the item moved from one location to another. A Tag reader could also be developed to specifically satisfy KSC requirements. The most promising frequency bands for the operation of the system are being evaluated by testing commercial off-the-shelf (COTS) products. Tag collision resolution algorithms are also being analyzed.

A hand-held directional reader/locator, with an extended range to help locate lost tools, was developed and is being tested. This Tag locator will need to sense the presence of a Tag and possibly estimate the distance from the locator to the Tag.

Key accomplishments:

• A portal with two antennas operating at 915 megahertz was built and is undergoing testing and characterization.
• A highly directional reader was prototyped and successfully tested.
• Software for the real-time update of Tag information was developed.