Indoor location technology achieving sub-meter accuracy

Indoor location positioning is currently one of the holy grails of the mobile technology world. With hundreds of millions of people using mobile-based GPS applications every day, the demand is clearly huge for location-aware mobile apps. There are over 150 companies developing indoor location technology, and a number of well-known technology approaches, but bottom line, it's still reaching market.

One of the key challenges in developing and deploying indoor location technology is clearly how accurate it is. Many indoor location systems, including those based on Wi-Fi or Bluetooth signals, are accurate only to within 5-8 meters. In many applications this is fine. If I want my phone to know what store or coffee shop I'm in, 5-8m accuracy is sufficient to distinguish Starbucks from JC Penny. But if I want my phone to know if I'm standing in front of the pretzels or the potato chips in the supermarket, I need better.

As a side point, GPS outdoors is only accurate to within 3.5 meters or more, at least in its mobile device form. But when you're driving with your favorite GPS app, the app will do what's called "snap to road" to make the location positioning appear a lot more accurate than it is. This is why, for example, if your planned route is to exit the highway, and you choose to stay on the highway instead, your phone will think you've taken the exit until your position on the highway is sufficiently far from the exit ramp. So when we talk about accuracy in indoor location technology being only 5 meters, this is roughly the same as GPS, it's just harder to fake (er, compensate) indoors.

A newly updated report from Grizzly Analytics analyzes technologies from 25 companies that achieve sub-meter accuracy, meaning that the location calculated by the system is within one meter of the actual location. A previous version of this report, from 7 months earlier, covered only 17 companies, so the number of companies achieving this high level of accuracy is going up as the technology in the area matures.

Only two of the systems profiled in this report use the "standard" indoor location approaches such as Wi-Fi, Bluetooth/BLE and motion sensing. It's simply very hard to get systems based on these technologies down to one meter accuracy, because of inherent challenges in estimating distance based on radio signal strength. Besides the two companies that succeeded using these approaches, virtually all those achieving sub-meter accuracy used other approaches.

The biggest change between the previous report and the newly updated report is the number of technologies that are based on cameras. Some companies are comparing the scenes seen by a device's camera to a database of scenes around a venue to see which location best matches what the device is seeing. Other companies use the running video stream from a device camera to plot the device's movement by measuring the changes in the scene. Camera-based approaches to indoor location used to be esoteric, but they are now increasingly achieving good results.

Many new systems, particularly industrial approaches that track tags instead of tracking smartphones, are using UWB. Unlike Wi-Fi and Bluetooth, UWB radio is engineered to enable much more accurate location and distance measurement. UWB-based indoor location systems started to reach market at the end of 2013, and more and more are coming out each month.

Finally, many of the systems delivering sub-meter accuracy, particularly on smartphones, are using new and innovative approaches. Some use entirely new methods of measuring radio signals, while others use innovative and esoteric kinds of signals that can be measured on smartphones. These are true areas of innovation, which are exciting technically and are more and more delivering great results.

Again, there is more to indoor location than sub-meter accuracy. Some approaches target tracking smartphones passively, regardless of the accuracy. Some approaches target low infrastructure cost and effort, at the expense of accuracy. Some are designed to self-learn a new environment, to enable universal applicability. But for those who need high accuracy, there are more and more sub-meter accuracy systems reaching market.

Is the day coming soon where apps will help hundreds of millions of people get around malls, stores, exhibitions, museums, office complexes, and other sites, as they do outside now? For those applications requiring accuracy, we're getting closer every month.

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