What Made the Intel CES Air Band Demo Work?
Why UWB-based location technology is taking off in embedded electronics for the IoT, Smart Home, and more
A string of top technology industry events kicked off 2016 and featured location-finding capabilities. The Intel® keynote at the 2016 Consumer Electronics Show, the Nokia booth at the 2016 Mobile World Congress and the Bosch keynote at Connected World 2016 showed off accurate location-finding and demonstrated how electronic devices can track their locations indoors.
Location technology is a mobile phone thing, right? Well, yes, but the hottest growth area for location technologies is now embedded in electronics, not only mobile devices.
At CES, Intel’s keynote included a stunning air-band demonstration, (Figure 1), in which musicians led by Ar Rahman played music with just their hands, no instruments. Chips embedded in the bands around their hands tracked the musicians’ hand movements. Tracking took place so precisely that the music sounded just like their hands hitting drums or other instruments.
Accuracy within a Few Centimeters
Can mobile phone technology track locations accurately enough and fast enough to make music? No, not yet. But chip-based location technology can. Intel’s demo used Ultra-Wideband (UWB) wireless chips from DecaWave to transform hand movements into music. These UWB chips track location to an accuracy of a few centimeters, with updates generated up to 2000 times per second depending on configuration.
At MWC, Nokia’s booth demonstrated very accurate location tracking as well. Tags from a company called Quantitec were tracked using a combination of DecaWave’s UWB technology and Quantitec’s motion sensing technology, with better than five cm accuracy. A screen at the show, also available online, showed the locations of booth staff and others as they walked around the show in real-time. Nokia was promoting this technology in connection with its 5G LTE antennas and its focus on next-generation networks for the Internet of Things (IoT).
At the Bosch Connected World event, Bosch showed location tracking as well, this time tracking the locations of drills as they are carried around an industrial site (Figure 2). The drills were tracked very precisely on a map as they traveled, again using a combination of DecaWave’s and Quantitec’s technologies.
These conference demonstrations are just a few examples of what chip-based micro-location technologies can do, but the same chips have already started to come to market in a wide variety of consumer electronics devices, including robots, smart cameras, drones, sports training products, keychain and wallet finders and much more.
UWB-based location technology is being embedded in electronics devices to enable them to operate in a location-aware manner. Grizzly Analytics has written that “Location-aware electronics can transform how people use electronic devices, as surely as GPS has transformed mobile apps.”
Why is UWB-based location technology taking off in the embedded electronics area? Other location technologies, including the commonly used Bluetooth and Wi-Fi approaches, use signal strength measurements to estimate the distance between a transmitter and a receiver. Unfortunately signal strength is a poor estimator of distance in places that include interference, including multi-path signals and non-line-of-sight.
Going the Distance
In an effort to improve distance measurement, engineers tried using time of flight measurements to estimate distance more accurately. But as Figure 3 shows, narrowband signals such as Bluetooth and Wi-Fi are still sensitive to reflections and noise, resulting in poor accuracy and reliability for time of flight measurements.
Ultra-Wideband also uses time of flight measurements to determine distance much more precisely, but UWB, as shown in Figure 4, uses impulse radio, which has very short (2ns) and sharp signals. Such signals can be measured accurately even in the presence of multi-path interference and noise. This results in effective and accurate measurement of time of flight, and therefore very accurate estimation of distance.
Implementation in Different Topologies
One strength of UWB technology is that it can be implemented in different topologies depending on the application requirements and constraints. For applications demanding the highest accuracy an infrastructure based topology is recommended. The infrastructure consists of locators, also called anchors, embedding UWB chips, which are deployed around a site. The locators pick the signals transmitted by moving objects, which also embed a UWB chip, and use trilateration or multilateration algorithms to calculate the position of the object. Multilateration, also called Time Difference of Arrival (TDOA), is simply for one chip—the tagged item—to transmit a signal. The chips receiving the signal reside in a synchronized infrastructure, which uses the time stamps of the signal to calculate the position via multilateration algorithms (Figure 5). A more accurate method—sub 10cm in 3D versus sub 30cm for TDOA—but which consumes a bit more power, is to use a two-way three-step ranging protocol as shown in Figure 6 between the tag and the locators and apply triangulation algorithms.
Unfortunately, it is not always an option to deploy infrastructure and other topologies are required for such applications. A good example of this scenario is emergency services entering an unequipped and unknown building, like fire fighters do. In such situation, leveraging mesh capability is the only solution. By using this capability, the system can measure the distance between all the nodes in the network, resulting in the calculation of a relative positioning (Figure 7) of the moving nodes, namely the fire fighters. The accuracy is slightly degraded—around 30cm—but in this topology the most important criteria is to reach an infrastructure free topology.
In still other contexts, a point-to-point topology can be valuable. An example of this is when one device wants to detect whether other devices are in the proximity. The idea is to create a virtual secure bubble around objects either to ensure they are entering/leaving the zone (geo-fencing) but more importantly to protect the data communication between those objects as the application can block communication if the two objects are not physically within a certain distance (Figure 8).
So now the question is, how will location awareness add intelligence and ease-of-use to the next electronic device YOU create?
Mickael Viot is Vice President of Marketing at DecaWave, a fabless semiconductor company headquartered in Dublin, Ireland.