Location Using Active RFID

E-mail Melanie Martella

Once upon a time, some bright spark said "let's add little radio ID tags to things so we can track where they are!" and after some growing pains and technological quick-steps, RFID has made steady inroads into enterprise asset management and logistics. Now, courtesy of Kris Pister (who developed Smart Dust, the self-organizing wireless network of tiny "motes") RFID may be learning a neat new trick.

Where It Is vs. Where It's Been
As Pister points out, in this eWeek article, current RFID technology tells you where your RFID-tagged object was the last time it was in range of an RFID reader. It doesn't necessarily tell you where your object is right at this minute. There are definitely times and situations where you want to know exactly where an asset is at any given time.

RF Time of Flight would give active RFID motes the ability to discern their location based on triangulation with other RFID motes. Something similar has been done with WiFi, using specialized tags that triangulate with multiple WiFi access points to provide location information. AeroScout has used this idea to help hospitals keep track of mobile monitors and equipment (and patients); track cargo containers in trucking depots; and other applications where you really want to know where something is right at this minute.

As Pister says in the eWeek article, "The sound bite on RFID is that most people think it's going to tell them where their stuff is at all the time. In fact, what RFID does is tell you where your stuff was the last time it went through a reader successfully. Contrast having to put in readers everywhere you want [information] to just having the tags know where they are and having that broadcasted every few feet."

This presents a radical shift in how RFID is implemented. With cheap tags and no need for readers would this allow smaller companies to get in on the act? I can't help noticing that this continues the trend to peg information to location. Sensor data are valuable. Sensor data arranged to give a deeper view of what's happening (think moisture levels in a field, vibration sensors on a dam, or GPS on cars tied into traffic monitoring) boosts its utility.

Tell us what you think—does this idea make RFID more attractive? What drawbacks do you see? How could you use this capability? Scroll down to the bottom of the page and post a comment!

Let us know what you think. Please scroll down and post a comment!