Home Internet of Things Aerospace Apparel Energy Defense Health Care Logistics Manufacturing Retail

Ask The Experts Forum

BlogsAsk The Experts ForumAre There Any RFID Tags That Can Transmit Location Details to a Reader?

Are There Any RFID Tags That Can Transmit Location Details to a Reader?

Posted By RFID Journal, 06.28.2014

Do any companies make tags that can report their positions?

—Name withheld

———

Yes. In 2009, RFID systems supplier Savi Technology unveiled an intelligent hybrid tag combining active RFID, satellite communications and Global Positioning System (GPS) technologies. The tag is designed to track goods anywhere within a global supply chain, whether they are waiting within a warehouse, being loaded onto a ship or sitting in a desert at a bare-bones military outpost (see Hybrid Tag Includes Active RFID, GPS, Satellite and Sensors). This, however, would be true of a normal GPS device.

RFID tags do not know where they are, so they cannot report their location. They simply send their unique ID and other data stored on a chip to a reader. With real-time location systems that employ active RFID tags, readers receive signals from tags and pass that information on to a back-end software application that calculates the tag's location based on information provided by readers, such as time of arrival, angle of arrival, triangulation or other methods.

Passive ultrahigh-frequency (UHF) systems generally provide a figure known as the received signal strength indicator (RSSI), which tells you how strong a signal from a tag is. A stronger signal means the tag is closer. This is an imprecise method of locating tags, however, because the signal could, for example, bounce off metal objects and reach the reader, thereby increasing the RSSI. This makes it difficult to get a precise calculation of a tag's distance from a reader.

With passive systems, you generally create a zone or a portal. Then, as you read each tag, you can know it either is within the zone or has passed through the portal. There are a few passive UHF fixed reader systems, such as Mojix's Star system (see The Brightest Star) and Impinj's Speedway xArray reader (see Best in Show: RFID Gets xArray Vision), that use antenna arrays to determine location. But again, the location is determined by the reader, not reported by the tag.

—Mark Roberti, Founder and Editor, RFID Journal

Login and post your comment!

Not a member?

Signup for an account now to access all of the features of RFIDJournal.com!

Next Post
How Many Passive UHF Gen 2 Tags Can a Si...
Previous Post
How Can I Build My Career in the RFID Fi...
PREMIUM CONTENT
Case Studies Features Best Practices How-Tos
RFID JOURNAL EVENTS
Live Events Virtual Events Webinars
ASK THE EXPERTS
Simply enter a question for our experts.
TAKE THE POLL
JOIN THE CONVERSATION ON TWITTER
Loading
RFID Journal LIVE! RFID in Health Care LIVE! LatAm LIVE! Brasil LIVE! Europe RFID Connect Virtual Events RFID Journal Awards Webinars Presentations
© Copyright 2002-2016 RFID Journal LLC.
Powered By: Haycco