We've discussed LED modulation for indoor location positioning before (here and here), and Acuity is not the only company bringing it to market. But the demonstration that I saw was very impressive, and Acuity is a huge player in the lighting space. The fact that a huge lighting company is focusing heavily on indoor location shows how strong the interest is in this area.
LED modulation is a technique that enables every LED lightbulb to transmit a unique identifier by making tiny changes to the lightwaves they shine. These tiny lightwave modulations cannot be seen by the human eye, but can be detected and decoded by the camera on a smartphone or tablet. Software on the devices can detect which ID's are being transmitted by nearby lights and calculate how far away and at what angle each of the lights are. The devices then use a technique called triangulation (or multilateration) to calculate their own 3D position and orientation.
Acuity reports that their solution can give indoor location position to an accuracy of 5-10cm, with vertical accuracy of 20cm. which is as accurate as any other indoor solution running on smartphones, and more accurate than most. This solution joins the ranks of other indoor location solutions delivering sub-meter accuracy. The tradeoff of the LED modulation approach is that mobile device cameras use a lot of energy, resulting in battery drain.
In these pictures we see the Acuity booth and their location positioning demo. See the demo in action in the video below.
If you look closely in this picture (click on it to see it full-size), we see an artifact of the LED modulation. The horizontal lines across the light do not show in pictures taken of other lights, and are due to the LED modulation that signals this light's ID.
The biggest trade-off in this approach to indoor location, of course, is the requirement to replace a site's lights with Acuity's LED lights, and to equip them with the Acuity controller that carries out the LED modulation. Acuity and others are promoting their solution in terms of long-term savings on electricity and maintenance, but it is still a cost that must be considered.
Acuity is not the only companies delivering VLC technology in LED lighting. GE Lighting and others are delivering similar solutions, and Qualcomm QTI is delivering related technology, and others are researching the area. But Acuity is a company devoted to lighting, and bottom line, their technology looks great.
One interesting aspect of Acuity's solution is that they are also using BLE beacons to track a device's location, albeit less accurately, when it is in the user's pocket. This enables their solution to deliver geofencing, and "waking up" when nearing a particular area and notifying the user of a reason to open up the device.
LED modulation for indoor location positioning has been the subject of R&D for years, and it's great to see it continuing to reach market! Learn more about VLC and other indoor location technologies in this comprehensive report.
Now check out the video of the Acuity demo.....