Indoor Passive Visible Light Localization: A Case of the Novel Rake RGB-LED Series Detector

In this article, we present a system PA SAL to explore the feasibility to enable visible light localization without adopting three practices as follows: 1) the LED as the transmitter modulates the signal; 2) the object of interest as the receiver carries light-sensing devices; and 3) place a large number of photodiodes in indoor environments. Specifically, we exploit the photoelectric characteristics of LED and spectral selectivity of RGB-LED to design an RGB-LED unit as both the transmitter and receiver. Inside the RGB-LED unit, we use the novel rake RGB-LED series layout perspective to increase the direct current response and sensing range of the detector, instead of simply combining a large number of monochromatic LEDs. Furthermore, we propose a joint received intensity positioning algorithm, which effectively recognizes the direction of the object, to achieve localization. In the end, we prototype PA SAL with off-the-shelf devices, and extensive experiments demonstrate that our PA SAL system could accurately sense the object and achieve localization. We believe our PA SAL system offers a new perspective to achieve both sensing and localization, and could serve as a promising complement to existing solutions.