Research On Visible Light Positioning Distance Compensation Method Based On RSS

With the popularity of LED in the world,visible light communication is also getting more and more research and attention.Due to incomparable advantages in many aspects,visible light communication is gradually attracting attention in short-range wireless communication and is considered to be one of the important communication methods in the future.Based on the analysis of the characteristics of visible light communication and the analysis of the complexity of several commonly used positioning algorithms,an visible light communication indoor positioning system based on RSS and TDMA is proposed.The system includes a transmitter,a receiver,and a location display terminal.The accuracy of the received light intensity is critical for RSS-based visible light indoor positioning systems.The factors affecting the accuracy of the received light intensity are analyzed from the three aspects of the LED,the visible light communication channel and the PD.Corresponding improvement measures are proposed.The system assumes that the luminous intensity of the LED is known and fixed,but the aging of the LED and the change of temperature will change the luminous intensity of the LED,thereby affecting the positioning accuracy of the system.Aiming at the effect of temperature on the luminous intensity of LED,a temperature-compensated LED driving circuit is designed.Aiming to the effect of aging on the luminous intensity of LED,the improvement of localization algorithm was proposed to compensate.The system assumes that the received light intensity of the receiver is direct light intensity,but the reflected light generated in the indoor environment will be mixed with direct light,which affects the positioning accuracy of the system.Four improvement measures are put forward:the larger light intensity values of LED is used for positioning,the smaller reflection coefficients materials is used to decorate the wall,reduce the distance between LEDs,and conduct the secondary positioning.The system assumes that the photoelectric conversion of the receiver is linear,but the linearity of the photoelectric conversion is related to its amplification circuit.By analyzing the advantages and disadvantages of several typical amplifier circuits,an amplifier circuit using a bootstrapped current-voltage converter as a photodiode is proposed,and the circuit performance is verified through circuit simulation in PSpice.Based on the above partial improvement improvement measures,the hardware and software design of the transmitter and receiver were performed.In the laboratory environment,the visible light communication indoor positioning system was tested.Test results:The maximum positioning error is 0.15m,the average positioning error is 0.058m,the variance of the positioning error is 2.68x10^-4m²,the number of positioning points which positioning error among the between 0.04-0.06m is the largest,and the positioning error of 94%is less than 0.1 m.