RIGHT HERE, RIGHT NOW

Logistics Insight Asia, 1/1/2008

Real-time location systems (RTLS) can pinpoint the position of your critical assets and are seeing increasing innovation and rapid growth.

BOB TREBILCOCK reports.

Not having the right part for a manufacturing process or the right inventory for an order can bring a factory or warehouse to a screeching halt. That’s where real-time location systems, or RTLS, come into play. These solutions use active and passive RFID technology to track the location of critical assets to within a few feet in real time. That said, not all RFID solutions include real-timelocating capabilities.

“In an RTLS solution, you have all the capabilities of an RFID system,” says Matt Armanino, Executive Vice President, WhereNet, a provider of RTLS solutions using active RFID tags. “But you also get the addition of a layer of software that allows an RFID tag to be located on a real-time basis with x,y coordinates.”

The solution works because the RTLS tag is programmed to broadcast a signal identifying its location at regular intervals. The signal passes through that layer of software to calculate a location.

How accurate is an RTLS solution? Depending on the technology being deployed, RTLS systems can track an asset to within a few feet of its actual location.

THE TECHNOLOGY
Not all RTLS systems work the same way. Time difference of arrival (TDOA) solutions – also known as triangulation – use three RFID readers to receive a signal coming from an active RFID tag. The readers record the time they receive the signals and forward that information to a central location.

The central location measures the time difference between the three signals to triangulate a location. TDOA solutions require a direct line of sight between the tag and the reader. For that reason, they work best outside, or in facilities with high ceilings and open spaces.

Received signal strength indication (RSSI) solutions, on the other hand, start with a map of the strength of the radio signals at various points in a facility. When a radio frequency (RF) signal is introduced into that environment, RF access points read the strength of the signal. The system then compares the signal to the archived fingerprint to determine a location. Due to the vagaries of a radio frequency, including interference, RSSI solutions work best in tight indoor environments.

WiFi solutions use specially designed WiFi-enabled tags that communicate their location over an existing 802.11 wireless infrastructure.

And a handful of suppliers are taking the RTLS-over-WiFi concept to a new level by coupling it with ultrawideband (UWB) sensors that not only piggyback on the user’s existing wireless infrastructure, but also offer considerably larger fields of view (15 to 60 meters) than earlier RTLS solutions. That reduces the number of reading devices (and costs) needed to provide coverage within a given area. Battery-powered UWB tag costs, which range between US$20 and $80, restrict current applications to high value asset tracking.

And sensor technology, in addition to providing information about the real-time location of an asset, pairs RTLS technology with sensors to monitor the physical condition of an asset, which might include attributes like the temperature or humidity of a storage area.

Application Areas
ABI Research’s Mike Liard says the automotive industry was the earliest adopter of RTLS, using the technology to track components like engine blocks and transmissions or parts containers. The transportation logistics industry was a close second, tracking containers or trailers in a port.

“Over the last few years, we’ve begun to see applications in new industries, like healthcare and pharmaceuticals, along with the mining industry, which is piloting the technology to track miners at work. In that instance, it’s literally a matter of lifeand death,” says Liard.

“When I think of RTLS applications, I think of tracking high risk and high value assets with a high ROI. If you look at the different applications of the technology today, they fit those themes,” he notes.

Generally, today, applications of RTLS systems encompass: • Tracking the location of trailers and their contents in the yard • Tracking the location of totes and containers for parts replenishment or work-in-process on the factory floor • Tracking the location of finished goods as they move through inspection, testing, staging and loading onto a trailer

Finding Value
Regardless of the technology, RTLS systems allow users to automate business processes that have been done manually for years and to collect more information than has been possible in the past.

“Users are deploying the technology because they need to have real-time connectivity to their mobile assets,” says Armanino. “You find many companies that have spent millions on decision support systems that are only as good as the timeliness of the information you’re feeding them.

“An RTLS system bridges the data divide between physical assets, a mobile workforce and a real time enterprise or execution system.” Mike Liard of ABI Research, points out some of the reasons for the fast growth (36 percent CAGR) of realtime location systems.

“With the addition of real-time locating technology, you not only know what you have, but where that asset is located in real time. It’s like locating a needle in a haystack. With that visibility comes two side benefits that are proving to be as valuable as the first: asset utilization and asset optimization.

“Once you know what you have and where it’s located, you can track how that asset is being utilized and whether it’s being optimized,” says Liard. “You can begin to delve into the choke points around your asset management.”

There is a difference between simple asset management and real-time Bob Trebilcock is Editor at Large, Modern Materials Handling (www.mmh.com). locating systems (RTLS). The first is used for keeping track of assets that may come and go, like returnable containers or pallets. An end user may want to track when a container enters or leave a facility, for instance, to know how long it was in the field. But it isn’t necessary to know exactly where that container is at all times.

A real-time location system (RTLS), on the other hand, can track the location of a mobile item in real time. With that information, you know how long an asset has been sitting in one place instead of being used.

“With RTLS, you’re not just tracking whether you have the asset, you’re tracking the physical location of that asset,” says Gary Latham, director of industry solutions for WhereNet.

“When you implement an RTLS solution, your employees spend less time looking for your assets. A materials handler, for instance, isn’t driving empty as often, which translates into higher productivity of your labor and better utilization of that asset,” notes Latham.

Bob Trebilcock is Editor at Large, Modern Materials Handling(www.mmh.com).