One of the most difficult challenges of flying indoor is indoor-navigation. Since GPS cannot be used indoor and is not fast and accurate enough, we use Philips systems to accurately determine the position of the drone in a room. More information about the Philips light system can be found here: http://www.lighting.philips.com/main/systems/themes/led-based-indoor-positioning.html
Currently, Blue Jay is still working together with Philips on the indoor navigation system called Visible Light Communication (VLC). Together with Philips, NXP and the TU/e, a demonstration in an innovative healthcare setting is initiated, planned for June 2017.