Impact of wavelength dependency of LED and photodiode in visible light positioning

The wavelength dependency of LEDs and photodiodes in RSS-based Visible Light Positioning systems is sometimes omitted in the calculations. This study investigates the consequences on the accuracy of this approach. A simulation-based assessment is performed, where a single link is considered. The received signal strength is used to estimate the distance between LED and photo-diode. Results are obtained for different phosphor coated LEDs and photodiodes. It is shown that neglecting the wavelength dependency results in distance estimation errors in the order of 10 %. This severe degradation would undermine the achievable accuracy of VLP systems (order of centimeters). The result shows that regardless the used photodiode, LEDs with a high correlated color temperature are more prone to distance estimation errors in comparison with low correlated color temperature LEDs.