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 simulationbased assessment is performed, where a single link is considered. The received signal strength is used to estimate the distance between LED and photodiode. 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.