Ever since the FCC first opened up the ultra-wideband (UWB) radio spectrum for unlicensed commercial use in 2005, UWB location systems have generated a lot of excitement as one of the “sexier” IoT technologies. This is largely due to the level of location precision afforded by ultra-wideband positioning systems. UWB indoor positioning systems are able to pinpoint location in real time to within 20 centimeters or less.
UWB can achieve this accuracy thanks to the large swath of spectrum―hundreds of megahertz―it uses to transmit messages. Because the ability to accurately measure the “time of flight” of any radio wave is a function of bandwidth, signals that are very broad in frequency can be accurately measured in terms of the time it takes for an encoded signal to travel from a transmitter to a receiver. The use of a wide-frequency spectrum means that the signal can be short in length. With UWB the signal is transmitted with low power, preventing interference with other systems using the radio spectrum such as cell phones and police radios.
While pinpoint accuracy may be of primary importance for some applications, it’s not the only valuable metric for a real-time location system (RTLS). Cost and ease of implementation are other factors that must be taken into consideration when choosing an indoor tracking system. The following examines the pros and cons of ultra-wideband RTLS.
One of the use cases where the location accuracy of a UWB positioning system offers obvious benefits is in warehouse automation. Companies like Amazon have huge warehouses filled with hundreds of thousands or even millions of different items; profitability hinges on managing labor costs—which means giving employees a way to quickly locate items when they are ordered by customers.
With a UWB RTLS, all the various items in a large warehouse can be easily mapped. Scanners equipped with location tags transmit information about the location of each item as it is scanned into stock by workers. Information on items’ locations in three-dimensions is recorded so they can be easily retrieved to fill customer orders.
Safety is another area where the accuracy of ultra-wideband positioning can be beneficial. For example, in a manufacturing plant where workers need to maintain a minimum distance from a piece of machinery, a UWB location system can signal the machine to shut down if a worker strays into the danger zone.
While no other existing indoor tracking system can match the location accuracy of UWB, that level of accuracy comes at a cost. The infrastructure and location tags for UWB systems are very expensive—as much as 10 times more costly than tags and readers for a Bluetooth (BLE) system such as AirFinder, which can achieve accuracy within a one-to-two meter range. In many cases, users of UWB systems find that they really don’t need pinpoint location accuracy, and “dumb their system down” to provide location within a zone, which a BLE system can provide at a much lower cost.
In addition, UWB location systems require at least three receivers to receive signals from tags. These readers are very expensive and they must be precisely synchronized down to the nanosecond for the system to calculate location accurately. In many installations, the readers are connected by cables to keep them in sync, which adds to installation cost and difficulty.
There is also a much higher level of complexity in the installation of a UWB system than there is with a BLE system like AirFinder. Reader locations for UWB must be precisely anchored in order for the system to work. This requires careful design before installation. In contrast, AirFinder is much more flexible in the positioning of receivers, and can easily be expanded as needed.
For applications where pinpoint location accuracy is needed for productivity or safety, ultra-wideband location technology is the best option. But due to the cost and complexity of installing a UWB RTLS, businesses should consider whether they actually need to be able to pinpoint the location of assets, materials, and workers—or if they can accomplish their goals with more general location information. Unless pinpoint accuracy is needed, a BLE or WiFi location system can do the job at a much lower cost.
If you’re considering implementing a real-time location tracking system to track assets, materials, or workers, check out Link Labs’ free webinar, Beyond GPS: Next Generation Indoor/Outdoor Tracking and Monitoring. Link Labs CTO Brian Ray and VP of the AirFinder Product Division, Dominic Marcellino, discuss how to leverage new Internet of Things network technologies for low-cost, seamless indoor/outdoor tracking and monitoring.