RFID Baggage Tracking Solution Helps Keep SFIA Secure Part 1

The challenge is impressive in the new $3.2 billion International Terminal at San Francisco International Airport (SFIA). At peak travel times, more than 8,000 passengers and 14,000 pieces of luggage go through the terminal per hour. A 7-mile conveyor system moves bags from the glittering ticketing concourse to the loading areas in the bowels of the terminal for departures on one of 24 international air carriers, and back to baggage claim for incoming flights.

During the past three years, a $9 million radio frequency identification (RFID) technology-based checked baggage inspection system was developed and implemented for the terminal, which opened last December. The system received FAA functional certification in May, meaning SFIA will receive federal reimbursement for both it and a $14 million CTX-9000 Explosive Detection System (EDS) made by InVision Technologies.

Although at present the RFID system comes into play only for a small percentage of bags targeted at check-in for EDS screening, the integrators say it can be easily expanded to handle all baggage tracking and sortation.

Safety first, tracking second
"Our mission is simple: to make this the most secure airport in the world," says Mark Denari, manager of Aviation Security for SFIA. "We can guarantee the flying public that FAA aviation security standards are exceeded."

Denari makes that promise with confidence. The Checked Baggage Inspection System (CBIS) is the first of its kind to be installed in a "common-use/multi-use" terminal shared by all international air carriers. It's the first to be fully integrated into an airport's automated baggage handling system, and it's also the first to be based on 2.45GHz RF technology.

SFIA's planners appear to have been visionary. The FAA has indicated it will require all U.S. airports to X-ray checked bags aboard every international flight by 2006. Some industry watchers predict that even domestic baggage will be subjected to automatic X-ray before loading by the end of the decade.

Of course, safety is an issue that is paramount for every passenger and crew member on every flight every day-especially for international flights.

In December 1988, an explosion ripped apart Pan Am Flight 103 bound for New York from London over Lockerbie, Scotland, killing all 259 people aboard and 11 people on the ground. The explosion was the result of a bomb planted by a terrorist.

Nearly eight years later, in July 1996, an explosion took down TWA Flight 800 over the Atlantic Ocean shortly after takeoff from New York's Kennedy Airport on its way to Paris, killing all 230 aboard. The FAA eventually determined the probable cause was a spark in the fuel tank. But initially, some speculated that the explosion was the work of terrorists. As a result, a White House Commission on Aviation Safety and Security, headed by Vice President Al Gore, was created.

In 1997, the commission recommended the FAA introduce a passenger profiling system to identify passengers who should be given closer scrutiny than others. In addition, the FAA began to require that airlines perform "positive passenger-bag matching" (PPBM) to ensure that, if a passenger does not actually board the flight, the bags do not board that flight either.

Late in 1997, the FAA began rolling out its Computer Assisted Passenger Prescreening System (CAPPS). Passengers meeting the unpublished criteria were singled out as "selectees" and physically escorted, along with their bags, away from the check-in area by security guards. The passenger and his/her bags were then physically searched, often resulting in delayed or missed flights. But since the CAPPS system targeted people of color-especially Arabs-this procedure was protested by civil rights groups such as the American Civil Liberties Union and resulted in congressional hearings in 1998.

Even before the hearings, the FAA was investigating whether RFID-based tracking systems, combined with explosive detection systems, could make the process of identifying and searching the bags of "selectee" passengers completely transparent to the public.

To encourage buy-in, Congress approved funds to reimburse airlines and airports for FAA-approved explosive detection systems, such as SFIA's CTX-9000. Although some European airports are using RFID for security applications, Northwest Airlines is the only U.S. carrier to have installed such a system, which it uses at its hub at Seattle-Tacoma International Airport. At SFIA, upon approval, FAA will also reimburse the airport for the cost of the RFID-equipped conveyor system because it is integral to the security function of the CAPPS program there.

Northwest's 2.45GHz RFID system (from SCS) employs re-usable tags that are manually removed before bags are loaded on the airplane. SFIA chose 2.45GHz technology and re-usable tags, completely automating the process.

A system ready for anything

For now, the RFID system only comes into play for the 5% to 10% of bags chosen for extra screening. But Paul Elizondo, director of systems integration for Single Chip Systems (SCS), which supplied the RFID tags and antennas, says the fully integrated system could be adapted to handle all baggage.

"They have in place a system which would allow them to do 100% baggage tracking and sortation," Elizondo says. "The infrastructure is in place. The system can handle 25,000 bags per day."

"They've just built this brand-new terminal, so they may want to make sure this system works with all the other systems they have," says Mark Ealing, project manager for Ultra Electronics, the system integrator. "But I think they will eventually expand their system to even include features like remote check-in from hotels and car rental counters. This would require a very accurate system. RFID is a technology that can deliver that."

Design over comes metal interference
Elizondo says 2.45GHz technology was chosen for its superior read rate in narrow fields, as well as the lower cost of 2.45GHz tags. Currently, the tags cost slightly less than $1, but Elizondo expects the price to drop as production rises. The adhesive-backed tags are inserted inside a normal bar-coded label, with the orange half of the tag sticking out.

There are 12 RFID antenna arrays, six on each side of the two-winged terminal. The arrays have a 50- to 60-inch read range. One of the primary challenges was that the conveyor readers are fairly close together, within about 60 feet of each other, because all the X-ray systems are in the same general vicinity, Elizondo says.

"This is the first time such a system has been used this way in an airport," Ealing says. "We had to design a system that would have several readers around a conveyor in close proximity to each other, without interfering with each other. By using the very focused field of 2.45GHz technology, we believe we've achieved one of the Holy Grails of RFID-we can establish that a tag is on a particular bag, in a particular location at a particular time, not just in a certain vicinity. The 2.45GHz field gave us a nice clean starting point, so when a bag crossed that line, we knew where the bag was in relation to that field."

In each array, six antennas are attached to an aluminum frame that surrounds the non-metallic part of the conveyor. Two antennas are mounted on top, one on each side and two on the bottom.

Ealing says one of the special features of this system is that the antenna arrays are built on a frame that surrounds a standard conveyor system. Usually, Ealing says, RFID applications like this require a tunnel system around the conveyor, which is much more expensive and makes maintenance and installation much harder. SCS' proprietary RF protocol allows the readers to be synchronized so they all transmit and receive information back at exactly the same instant. This protects the scanners from mistakenly reading a tag on a nearby conveyor.

Another challenge was developing a special plastic material for the conveyor system that would not block or reflect RF energy. BAE, the conveyor vendor, developed a proprietary non-metallic material that replaces the conveyor's metal framework wherever the RF arrays are installed. In another innovation, a special non-metallic material has been developed for the reflective curtains covering the entrance to the X-ray machines. This material reflects RF energy on one side and absorbs it on the other.

"We discovered that if two bags were too close together, it could create a potential readability problem," says Paul Foster, SFIA's aviation security analyst. "The array would try to read both tags. If two tags are picked up, both get sent to the CTX, but that adds more load at the Stage III screening. So BAE developed the special reflective curtain to keep the array from picking up a bag outside the curtain."