RFID-Reading Drone Tracks Structural Steel Products in Storage Yard

By Claire Swedberg

Dubai-based Age Steel is using an airborne RFID reader to inventory and locate tagged bundles of pipes, plates and other items stored in its yard.

Age Steel, a United Arab Emirates (UAE) company that operates multiple steel yards in Dubai, has taken radio frequency identification technology to new heights, through its use of an RFID reader mounted on a small unmanned aerial vehicle (UAV), commonly called a drone. The Steel Yard Autonomous Tracking solution, provided by UAE technology services startup Exponent Technology Services, enables Age Steel to quickly and accurately track the locations of pipes, plates and other metal products stored onsite.

Age Steel imports structural steel products, such as pipes, plates, coils, angles and hot-rolled bars, and sells them for use on construction projects throughout the Middle East. The company operates three yards in Dubai and a fourth in Saudi Arabia, and the steel pieces at each location are stored in bundles. A staff member writes each bundle's ID number in chalk on its label. After that, approximately twice a year, personnel would conduct an inventory count of what was stored within each yard. If a bundle was purchased and needed to be picked and shipped from one of the yards, workers at that location had to walk around the yard manually searching for it. According to the company, this could be a time-consuming and highly unpleasant process, since temperatures in the yards typically reach 45 to 50 degrees Celsius (113 degrees to 122 degrees Fahrenheit). If the product could not be located, Age Steel would have to go to one of its own local competitors and buy the same item from them at an elevated price—meaning that there would typically be no profit, or even a loss in the sale, if the firm failed to negotiate a replacement.

An RFID-equipped drone flies over one of Age Steel's storage yards.

"We have seen a large upswing in business over the last 15 months, and the quantity of stock that is moving through our yards has increased dramatically," explains Raed Siddiqui, Age Steel's director. "The yard itself is in a state of expansion, and the ability to locate particular items of stock in a timely and efficient manner was becoming a challenge." He adds that "the increased pressure on our logistics team to receive stock swiftly has created challenges in our ability to track the tens of thousands of bundles of steel that are transiting our yard at any point of time."

The company sought a solution from Exponent, which attached passive ultrahigh-frequency (UHF) RFID tags to the bundles and then had an Age Steel staff member walk through the yard equipped with a handheld reader. But after trying that option, Age Steel deemed it too time-consuming.

Exponent Technology Services began searching for a better alternative, says Asam Khan, Exponent's chief operating officer. It realized that it required an automated way in which to collect RFID tag-read data within the yard. The firm was launched two years ago to provide software services, and became interested in RFID after seeing the data it could provide to one of its customers in the Chicago area when tracking waste that the company hauled. Exponent then provided an RFID solution for an aviation parts supplier in Dubai that also had a challenging RFID reading environment, including the presence of metal and high temperatures.

However, no one at the company had experience with UAVs, Khan says—not even as hobbyists. Therefore, he visited a local hobby shop to purchase a small drone, and attached an RFID reader to it to determine if he could fly the device over tags and capture their tag IDs. It worked well, he reports.

Throughout the next nine months, Exponent began developing software to create drone flight paths, and tested various passive UHF RFID tags and readers to ascertain which was the most effective. The company found, however, that active RFID tags could be more easily interrogated by a reader installed on a drone operating in a highly metallic environment.

Exponent Technology Services' Asam Khan

In May, Exponent and Age Steel tagged 1,000 bundles (selected to provide a representative sampling of items throughout the yard) in Age Steel's smallest yard with Omni-ID Power 400 tags, which operate at 433 MHz and employ a proprietary air-interface protocol. It then tracked them via two daily drone reads throughout one month, while comparing the results against those of 1,000 untagged bundles. The drone was equipped with an Omni-ID Link Gateway 433 MHz RFID tag reader, wired via a USB adapter to a tablet computer. The company found that while 300 of the untagged bundles went missing for at least some portion of that 30-day period, none of the tagged bundles were lost. What's more, Khan reports, the drone was able to read 1,000 tags spread across an area measuring 10,000 square meters (108,000 square feet) in size within five minutes, achieving a 98.2 percent accuracy.

"We agreed to the pilot with a fair dose of skepticism," Siddiqui says, "but were pleasantly surprised when it demonstrated the ability to consistently track the physical location of over 1,000 RFID tagged items with an accuracy rate of 98.2 percent."

The patent-pending solution that Exponent developed is now being installed at one of Age Steel's yards. Age Steel expects to take the deployment live on Oct. 15, with Exponent providing the inventory-management service, operating the drone and generating inventory location data and history for each bundle on a daily basis from its cloud-based software.

Each afternoon at 2 pm, as workers are changing shifts, and again around 10 pm, when the day's winds and dust have settled and most workers are no longer in the yard, Exponent will launch the drone onsite, which will have a preset flight path, speed and altitude. During that flight, which is expected to last for a total of only five to six minutes, the drone will pass over the tags and read each tag's ID. The drone's tablet will combine that ID with its own GPS location data, and then forward that information back via a cellular connection.

Each Power 400 tag also contains a passive UHF RFID inlay complying with the EPC Gen 2 specification. When the bundles are first tagged, the staff will employ an Intermec handheld reader to collect data about the bundle, such as where the products were produced, the grade of steel used during manufacture and other details. This information is encoded to the Power 400 tag's passive UHF inlay's 1 kilobit of memory. The passive tag can then be read in the event of exceptions, such as an individual in the yard wishing to read details regarding a bundle in front of him or her.

The active tag transmits its own unique ID, which the drone captures at a distance of 15 to 20 meters (49 to 66 feet). The GPS technology built into the tablet computer installed on the drone can pinpoint its location to within about 4 meters (13 feet). When sales or yard workers wish to locate a specific bundle, they can access the Exponent software, input the description, view the location data displayed on a map of the yard, and read the data written to the passive tag. They can also view how many times it was read, in order to determine how long the item has been in the yard.

The software not only spares workers time they would otherwise spend searching for bundles, but also provides historical data. For instance, Khan says, the company will be able to view which types of bundles are sold most quickly—and, as a result, better manage the locations of goods within the yard, with less frequently shipped items stored farther from the gate, and those sold more often located near the gate where they can easily be accessed.

Beginning on Oct. 15, the yard will begin tagging 1,000 new bundles each month until reaching a total of all 10,000 bundles (the yard's full capacity). It may then expand the system's use to include its other, larger yards. In addition, Age Steel is considering adding functionality to track workers and forklift data, by installing a Link Gateway reader on each forklift, as well as Power 400 tags on staff badges, so that the firm can track who moved which item, and where, and thereby offer bonuses to those achieving the highest efficiency ratings.

Siddiqui predicts "faster location of inventory, which will speed up the time it takes us to process an order, as the UAV will provide daily inventory checks. Less time will be taken trying to locate a particular item, and thus more stock can be processed with the same resources." Additionally, he says, his company hopes to be able to more accurately assess "which products and customers are taking us longer to process and why," based on the collection of inventory data indicating when a product is received and then shipped out. "This level of business intelligence will lead to further improvements in our processes, leading to more savings," he states. "We hope to see operational cost savings through less usage of our yard-handling equipment—for fuel, maintenance, wear and tear—as fewer stock movements will be required to process each order."