Exploring RFID’s Outer Limits
While radio frequency identification, or RFID, has been around a long time the technology is advancing and migrating into new uses and applications. Learn the different types of technology and how to deploy them in ways that will win over new customers.
Here is an example of multipurpose active RFID tags. X-ray view of photo ID access card, employee tracking, emergency evacuation identifier and smart card all in one “credit card”-size credential.
One of the guiding goals of “Tech Talk” is to explore and bring readers technologies that offer new and exciting business opportunities. In recent months I have become involved in a variation of an existing technology that I have come to realize most in the security industry are either unaware of, not yet involved in or do not yet fully understand. The technology application that I am referring to is ultra-long range (ULR) radio frequency identification (RFID) security.
RFID technology is not new. Actually, you may not know this, but it started with the British Air Force in WW II. Radio signals were transmitted from planes to identify if they were friendly. However, most of us are familiar with the more modern-day use of RFID that started in the 1970s with the United States Department of Energy developing a system to track nuclear materials.
Although for years RFID has had many applications in security, it was for the most part limited to a radio communication range of a few inches to at the most around 20 feet. Security professionals are mostly familiar with use of RFID tags and chips used in access control proximity cards or placed on retail merchandise for shoplifting control. However, today, if you know how to apply various RFID technologies you can implement systems that can reliably track valuable objects and pe rsonnel over large areas.
Let’s start by taking a look at some of the RFID system configurations available today. We’ll then examine some of the exciting applications that can be achieved, challenges overcome and solutions obtained.
Active/Passive Readers and Tags
Active Reader Passive Tags (ARPT) are the most common and widely used RFID configuration. The system’s readers send radio interrogation signals to be recognized by approaching passive tags. These passive tags, such as access control proximity cards, do not have internal power sources like batteries. What they do have is a small internal antenna that will use the power from the incoming reader’s interrogation signal to send back a small identifiable return radio signal, sometimes called backscatter, back to the reader.
The upside of an ARPT system has always been the low cost and small size of the passive RFID tags. The downside has been a short reader range and problems configuring readers for consistent “hands-free” reading of tags through access “chokepoint” portals. These systems are also referred to as passive systems.
To help compensate for the limited read ranges of passive tags, the Battery-Assisted Passive (BAP) tag was created. This type of RFID tag uses a small internal battery to boost the returning backscatter signal to the reader and thereby increase the read range. The BAP tag is still limited by and dependent on an interrogator signal from an active reader. Many mistake this for a passive tag when it is actually an active tag due to its own internal power source.
Passive Reader Active Tags (PRAT) apply to an RFID system designed with a totally passive reader and active tags. Since the readers are very sensitive they can read active tag encrypted beacon ID signals at adjustable ranges of a few inches to several thousand feet! This allows for asset and hands-free personnel tracking with a smaller number of readers and over a very large area.
Some application examples of a PRAT system are the ability to verify and track aircraft traffic in an airport, 24/7 asset tracking, and tracking students on a high school campus. The active tags have a very robust signal that is powered by an internal battery. Today’s applications are made possible by the power efficiency of these active tags as they can typically send a 1.5-second beacon pulse with a battery life of five years. This system is also called an active system.
PRAT Packs Powerful Possibilities
As security professionals, we now need to take a moment, step back and truly absorb the capability of an ULR PRAT system. First off, since we have constant radio polling supervision, we can now monitor mobile assets and personnel on a 24/7 basis within a facility. What have always been some of the biggest objections by prospects on the tracking of assets with standard ARPT-type RFID systems? That passive tags can be shielded at access chokepoints using a metal enclosure similar to the use of foil-lined booster bags on passive retail tags.
However, now with PRAT systems and 24/7 asset supervision you will get an alarm as soon as a secured item is either moved to another area or there is tampering of the active tag. Active tags come with a variety of mounting and tamper detection configurations such as tag removal and motion detection. This takes care of another common comment on compromising RFID, which is that a tag can be removed from the asset, left behind and then the valuable asset removed.
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About the Author
Bob Dolph, SSI Contributor
Bob is currently a Security Sales & Integration "Tech Talk" columnist and a contributing technical writer. Bob installed his first DIY home intercom system at the age of 13, and formally started his technology career as a Navy communication electronics technician during the Vietnam War. He then attended the Milwaukee School of Engineering and went on to complete a Security Management program at Milwaukee Area Technical College. Since 1976, Bob has served in a variety of technical, training and project management positions with organizations such ADT, Rollins, National Guardian, Lockheed Martin, American Alarm Supply, Sonitrol and Ingersoll Rand. Early in his career, Bob started and operated his own alarm dealership. He has also served as treasurer of the Wisconsin Burglar and Fire Alarm Association and on Security Industry Association (SIA) standards committees. Bob also provides media and training consulting to the security industry.
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