Chris Anderson 2018-03-05 01:21:47
Antennas play a key role in the quest for precise location accuracy. Many wireless communications system designers expect highly precise location accuracy to be a breakthrough technology of 2018. Although outdoor applications such as the connected car and the promise of autonomous vehicles have drawn much of the industry fanfare, the buzz has grown around the requirements for more high-precision location capabilities for indoor applications. Antennas are playing a key role in the quest for precise location accuracy because knowing the relative location of an object in relation to another is becoming increasingly important to serve the new internet of things and other emerging business cases. High Accuracy A growing list of applications require centimeter-level accuracy. These include crowd management at busy locations such as airports and entertainment venues, warehouse management, the use of unmanned aerial vehicle drone technology across a variety of industries, public safety, health care applications and others that demand much more precise location capabilities. For many business cases, accuracy . Sometimes as precise as centimeter-level . Is a requirement. New Approach Obtaining that level of precision, however, has been a challenge. GPS, long a mainstay outdoors for providing location within a few meters, doesn’t always work accurately or consistently indoors. Technologies such as cellular, Wi-Fi and Bluetooth have been repurposed for location use and can provide a general location of an object indoors with a wide range of accuracy that can vary from several feet to tens of yards. But for a growing list of business cases, feet or yards is not good enough. Precision matters, and thus companies need a new way of approaching accuracy. The problem with re-engineering existing connectivity solutions is that they weren’t designed as locations systems with accuracy-first in mind. New advancements have helped improve Wi-Fi to meter-level accuracy, for example, through the Wi-Fi Alliance’s introduction of its Wi-Fi Certified Location feature, based on the Fine Timing Measurement Protocol in the IEEE 802.11‑2016 standard. The technology calculates the distance between the Wi-Fi device and the access point by measuring the round-trip time of the Wi-Fi signal. It cannot support business cases that require more precise location capabilities. Path to Ultra-wideband This need has spurred companies to look outside of technology primarily developed for data connectivity to other solutions that hold promise. This search has led many companies to ultra-wideband (UWB) technology. As low-power technology, UWB can transmit large amounts of data short distances over a wide spectrum of frequency bands from 3 Ghz to 10 Ghz. It works on many of the same principles as GPS technology; however, because GPS can transmit much stronger signals, it’s a much better solution for outdoor use. The low power requirements of UWB mean increased battery life for sensors and tags, leading to a reduction in overall operational costs. UWB is now emerging as a highly credible method for determining precise indoor localization of assets, objects and people. Working as a type of “indoor GPS,” UWB can detect the proximity of an object or person to some other object with incredible accuracy. Whereas Wi-Fi and Bluetooth-enabled beacon technologies can offer meter-level positioning, UWB can offer much more precise location accuracy. Part of the success of UWB comes from the development of high-quality, high-performance antennas built specifically to enable precision location. Antenna vendors are incorporating additional benchmarks to further optimize the signals for performance and precision. For UWB applications, it’s important the antenna does not distort the signal when it is radiated. However, with UWB, all frequencies are radiated at the same time across a large bandwidth, making it difficult to tell, if there are problems, which antenna is at fault. Antenna vendors are looking at new parameters such as group delay and fidelity factor and are incorporating these into nextgeneration antenna measurements to characterize how the antenna radiates signal pulses. The antennas then optimize the pulses across all of the frequencies. For indoor applications, antenna size is also a big factor because of the size of the UWB-enabled tags that are required. One common UWB application uses barcode scanners in the supply chain and warehousing. The application sends a UWB pulse when a barcode on a box is scanned. Based on the pulse, the system then reports precisely where the item is, within a few centimeters. Precision location such as that might not be required in a warehouse of large appliances or automobiles, but it would be required in a warehouse for a components manufacturer or distributor. “Part of the success of UWB comes from the development of high-quality, high-performance antennas built specifically to enable precision location.” Small Form Factor Because of these size requirements, antennas need to have a small enough form factor to be mounted onto a printed circuit board or embedded inside a device, without sacrificing performance where space is limited. The capability to adapt to the specific applications in terms of size, shape and electronics environment is important as end products become increasingly smaller. Antenna manufacturers have accepted that challenge, creating next-generation designs that feature several form factors, including chip and flexible adhesive antennas, for a variety of new or emerging requirements. What makes UWB a solid solution for indoor short-range positioning is that it can be used anywhere indoors that anchors can be set up, even underground in a parking garage, for example. The tags work within a few dozen meters of the anchors and need to see four anchors at the same time to establish location. The system and tag each have antennas and can conduct bidirectional communication, so both system and tag can know tag location. Anchors need to talk to each other either in-band using the UWB signaling or out-of-band using a different wired or wireless communication channel. Antennas need the flexibility to account for a variety of environments and applications. Custom cables and connectors are also key to developing flexible antenna solutions for these myriad environments. As companies continue to build business cases for indoor applications that require precision accuracy, the industry needs new approaches to achieving it. Antennas are using new technologies and new form factors to deliver centimeter-level positioning across a variety of vertical markets. Chris Anderson is chief technology officer at Taoglas, where he manages and coordinates global engineering resources. For more information visit www.taoglas.com.
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