New RTLS Module to Cut Active UWB Tag Cost

The DWM1004, Decawave's latest module, offers a low cost and low power consumption in a 30- by 15-millimeter package, for use on assets by small and midsized companies.
Published: July 29, 2019

Real-time location system (RTLS) adoption is still high-cost for small to midsized companies looking to manage their assets, and active tags can be among the most expensive aspects of such a solution. That’s been an entry barrier for many companies that want to track their assets or tools in real time, according to ultrawide-band (UWB) semiconductor company Decawave.

To address that high cost, Decawave has released the latest version of its DWM1000 series modules, priced at less than $10 apiece, that are small, low-power RTLS transmitters without a need for high processing or added functionality. The new model, known as DWM1004, is currently being tested by some of Decawave’s customers, with solutions expected to be made available to end users by the end of the year.

DecaWave’s DWM1004 module

The DWM1000, released in 2014, was Decawave’s first UWB active RFID module to ease the development of RTLS tags (see DecaWave Intros Ultra-wideband Active RFID Module). Subsequently, the DWM1001 module was released last year with features such as Bluetooth Low Energy (BLE), an accelerometer and high processing power to enable edge computing.

Like its predecessors, the DWM1004 complies with the IEEE 802.15.4 UWB standard and is designed to ease the development of hardware for solution providers that offer RTLS technology for locating assets. Users of tags incorporating the modules are expected to include manufacturers, logistics providers, health-care facilities and farms. But the latest module is lower in cost, the company reports—without BLE functionality or a high memory processor, it can be small and cost less than $10.

The demand for RTLS-based technology has been growing, according to Mickael Viot, Decawave’s marketing VP, who says his company has sold several thousand evaluation kits, adding, “So we know there’s a lot of demand.” However, small to midsized companies face challenges when it comes to implementing RTLS technology for managing assets.

The tags that beacon their location to gateways for RTLS solutions can be expensive, and that, he says, has served as a barrier to adoption, especially for companies that don’t buy the tags in high volume. The cost of designing, gaining certification and finding a manufacturer is simply too high, Viot says. “So we decided to offer a module that is tailored to specific applications,” he explains, for which a lost-cost tag with a small form factor is needed, without the extra features that the DWM1001 models offer.

The DWM1004 is designed with an STMicroelectronics STM32L0 MCU that beacons its unique ID number at pre-set intervals and goes dormant when not beaconing. It has less processing power and consumes less energy than the DWM1000 and DWM1001 units. The module comes with an accelerometer to identify when a tag is in motion, enabling that tag to beacon, or to beacon more often, based on its movement.

Because the tag consumes almost no power while dormant (the accelerometer consumes a small amount of energy during such times) and requires less power to transmit, the battery life can be between seven and nine years with 1,000 beacons per day. This long battery life provides a significant reduction in the cost of ownership, Viot says, since it eliminates the need for frequent battery checks and tag replacement. The expense of labor hours required to locate tags, check them and replace batteries can be higher than the value of the tag itself, he says, adding, “We remove this cost.”

The tag can be read via standard UWB gateways that would receive its unique ID and employ UWB’s time and distance of arrival (TDoA) to calculate the tag’s location. Decawave’s existing customers (RTLS solution providers) have conducted early testing on the new modules and will now be able to design their own products to allow their customers to track goods with small active RTLS tags when asset tracking is needed. In the meantime, Viot says, companies looking to utilize RTLS technology with robotics or other systems requiring high processing of data on the edge could use the DWM1001. In other words, he says, scenarios in which the tag does not need to know its own location are best suited for the DWM1004.

Companies that will benefit from the DWM1004 module-based tags, Viot reports, include logistics firms and warehouses that must track pallets, manufacturers that need to manage assets or tools, and farmers looking to monitor cattle. The module measures 15 millimeters by 30 millimeters (0.6 inch by 1.2 inches), which enables the tag to be small enough to be attached to a hand tool, on the side of a pallet or in a cow’s ear.

Location accuracy, as with the other DWM1000x modules, is approximately 15 to 30 centimeters (6 to 12 inches) in 2D or 3D, based on raw TDoA data, while additional computing in cloud-based software could provide further granularity. For companies tracking tools, pallets or cattle, Viot notes, the reliability of the tags is the greatest priority, as opposed to tight location granularity. “Our goal is to enable the mass adoption of UWB-based RTLS systems,” he states. In the long run, Viot says, he envisions the module enabling the development of UWB tags that are affordable and readily available for end users.

The module comes with Decawave’s DW1000 chip with a data rate of 6.8 Mbps, so that it reduces airtime, thereby minimizing power consumption and the risk of interference. Its STM32L0 MCU comes with 32 kilobits of memory, enabling tag designers to embed Decawave’s TDoA tag software, or their own, as well as added features such as tag transmission rates. The module provides encryption to ensure the security of data in transit between a tag and a gateway.

The DWM1004 is expected to be certified by September 2019 to meet Federal Communications Commission and ETSIregulations, Viot adds, sparing developers the time and cost that would otherwise be required to gain approval from U.S. or E.U. regulatory bodies. That means the time to release new products could be reduced considerably, he says. “We’re reducing the time to market,” Viot states. “Someone could buy the module tomorrow and complete a tag within a couple of months.”

Later this year, the company plans to release a UWB active tag that includes the DWM1004 module and an IP67-rated casing with a battery holder.