As we know, GPS used indoors does not guarantee enough precision to be used for localization and navigation purposes. In fact, GPS signals are partially (if not totally) blocked by walls in closed spaces. At the time of writing this post, even big players like Google and Apple have yet to deliver a version of their mobile maps applications which would allow users to navigate indoor places as they do outdoors.
Other technologies promise to deliver indoor localization and navigation, including Wi-fi, Ultra Wide Band Tags, Bluetooth, Mobile Network Cells. Such techs have been available for quite some time, however all have issues preventing their successful adoption in the consumer market, in particular
• Low precision: radio signals do not travel freely in space. Signals bounce on walls and obstacles, and are absorbed by matter as water or the human body (which is mostly made of water). A radio receiver is not able to distinguish direct signals from reflected ones. Moreover, there is no way to determine the original strength of the signal coming from a particular antenna. Even with triangulation of radio signals from different sources the localization precision of radio signals-based systems is usually 5-7 meters or worse. Such precision is usually insufficient for localization as it could place the user in the wrong room, the wrong supermarket aisle, if not on the wrong floor
• Need for custom hardware: some of the technologies mentioned above, UWB (Ultra Wide Band) in particular, could reach better precision (up to 15-30 cm) on consumer devices provided it is used in conjunction with additional custom (and usually expensive) hardware
• High cost of deployment: to set up these localization systems in large indoor spaces there is the need to deploy a large and dense network of antennas and beacons. Each one of these devices requires calibration and maintenance with costs increasing with covered space.
Late last year (2019) the above picture was shaken by a couple of technical advances which laid the ground for a new hope
• Bluetooth 5.1 specifications came out
• Apple and Samsung started to include UWB chips in new devices starting from iPhone 11 and Galaxy Note 20
Bluetooth 5.1
Don’t be fooled by the minor version number increase, the 5.1 specification is a huge leap forward from the 5.0 specification. New features include an extended range (760 meters at 1Mbps and 1400 meters at 125 Kbps), faster connection time, improved data speed, and less power consumption. However, the most prominent new feature is certainly direction finding. What does it mean? Well, to keep it simple, two elements were added to the bluetooth protocol, namely AoA (Angle of Arrival) and AoD (Angle of Departure).
These two elements in Bluetooth 5,1 protocol allow a device to compute the direction from where the bluetooth signal is coming from, improving the localization precision to less than 1 meter.
Ultra Wide Band in mobile phones
Ultra Wide Band (UWB) is not a new technology. It dates back to the early 1900s when Guglielmo Marconi used spark-gap transmitters in transatlantic radio communications. The technology evolved significantly in the mid 1900s and it proved to be suitable both for radar and for communications purposes. Therefore from the 1960s to the 1990s UWB adoption was restricted to US military applications only.
In 2002 the Federal Communication Commission (FCC) eventually allowed the unlicensed use of UWB systems in radar, public safety and data communication applications. It was the beginning of commercial exploitation of UWB as a short-range communication technology. Since then, a number of successful UWB-based solutions for indoor localization and navigation hit the market, although all relying on custom hardware. But it was not until 2019 that mobile phone makers such as Apple and Samsung started to embed UWB technology inside their flagship phones, paving the way to new and exciting applications.
What is the advantage of UWB over other radio transmission technologies? To put it simply, UWB waves (within certain limits) can travel through walls and other obstacles, largely reducing the “reflection issue”. It results in UWB localization precision down to 10-30 cm, even better than Bluetooth 5.1!
Unprecedented application scenarios could leverage UWB. For instance, the US Military is experimenting this technology to enable vision through walls! How cool is that!? 🙂
Peer-to-peer localization techs
In addition to Bluetooth 5.1 and UWB, other emerging localization technologies promise to boost indoor localization, such as
Mesh Localization Networks: networks of mobile phones that are able to communicate with each other improving the precision, range and cost efficiency localization. This technology allows to build indoor localization systems that are able to scale size with marginal increase of the costs
Android and iOs cross platform communications: the recent collaboration between Google and Apple on the “Covid contact tracing” SDK to make their devices communicate with each other is almost unprecedented and it could open the way to a future coexistence of devices with different Operating Systems in the same localization network.
Conclusions
Going back to the three main issues which prevented the availability of suitable solutions for indoor localization, it is reasonable to expect such issues will soon be overcome by recent advances in technology
• Precision: UWB and Bluetooth 5.1 will solve the problem
• Need for custom hardware: mobile phones with UWB and Bluetooth are already out in the market. Eventually all mobile phones will have one or both technologies onboard
• High cost of deployment: Mesh Localization Network technologies and the possibility to use cheap consumer devices will dramatically reduce deployment costs.
Indoor localization has the potential to unleash a new category of exciting applications for consumers and business users. Imagine adding products to your shopping list and an app can navigate you through the aisles to collect the products from the shelf. Or as the grocery store manager, be able to track your customers wandering around your shop, like we do on the web with Analytics, and adapt the shop layout accordingly in order to increase revenues and customer satisfaction. Imagine smart price tags that are able to propose instant offers to single users when they approach them. And if you like airports more than shops, imagine an app able to compute the travel time to the gate similar to what Maps can do today outdoors. The possibilities are endless.
So….is indoor localization eventually coming? Well, I hope that at this point you won’t need the short answer 😉 but if you are still in doubt here you go… Yes it is!
