Indoor and outdoor geo-localization and navigation by visible light communication

The attenuation of GPS signals inside buildings has recently boosted research in the field of indoors navigation systems. Different solutions can be used to manage positioning and navigation services inside the buildings, that make use of different technologies. In this paper we propose an indoor navigation system based on Visible Light Communication (VLC). In this system navigation through a building is enabled by using the location information supplied by the lighting infrastructure. The application presented in this paper relates the use of robotics solutions within warehousing, a field where automation is directly related to reduce labor costs, minimize human error and create the potential to better use building space. In this paper we propose VLC based bi-directional communication among the infrastructure and guided vehicles to support navigation inside the indoors space of the warehouse and transmission of dedicated messages related to the operations managed by the vehicles. The communication network is supported by VLC emitters using tri-chromatic white LEDs and dedicated receivers based on a-SiC:H/a-Si:H photodiodes with selective spectral sensitivity. The downlink channel establishes the infrastructure to vehicle (I2V) link and transmits information through the modulation of the red and blue emitters of the RGB LEDs. Position information is provided by each LED lamp to the vehicle by suitable modulation of the RGB emitters. The decoding strategy is based on accurate calibration of the output signal. The uplink channel is used for the communication from the vehicle to the infrastructure (V2I). This link is established using a single optical signal. In this paper we present basic system requirements, give details on the network topology and discuss the methodology used to decode the multiplexed signal transmitted by simultaneous emitters.