| At present,wireless positioning methods,such as those based on radio frequency identification,bluetooth,and Wi-Fi,are commonly adopted for indoor positioning of robots.Visible light positioning technology has numerous advantages such as anti-electromagnetic interference,interchange lighting and communication,and anti-multipath interference.Based on the analysis of the characteristics of visible light communication channel and the analysis of the complexity and positioning accuracy of several commonly used positioning algorithms,this thesis proposes an visible light communication indoor positioning scheme based on RSS and TDMA.The program is mainly composed of Launch control system,Visible light transmitters,visible light receivers,mobile devices and so on.In this thesis,the design of cascaded amplifying circuit based on current-voltage converter and photodiode electrical model and the design of acquisition circuit based on noise analysis are introduced.For the purpose of the system working orderly,we design the software system of Launch control system,Visible light transmitters,visible light receivers.In view of the traditional RSS trilateral localization algorithm localization accuracy is not high,we design a multi-lamp non-linear weighting algorithm;In view of the problem of flicker and inaccuracy of light intensity acquisition in TDMA visible light communication indoor positioning system,it is pointed out that FDMA can solve the above problems effectively.Aiming at the problem of carrier distortion in FDMA,A phase-sensitive detection demodulation technique is therefore proposed to address this problem.This technique makes use of the distorted signal frequency spectrum characteristics and relies on the phase-sensitive detection demodulation method to suppress the harmonic interferences of higher orders.In the laboratory environment,the visible light communication indoor positioning system is tested.The test results show that the communication error rate is lower than 10-6for the vertical movement,horizontal movement and receiver tilt of the receiver,which satisfies the requirement of the positioning error rate of the positioning system.The positioning error of visible light communication indoor positioning system is less than25cm in the typical application scenario and less than 50cm in the extended application scenario,to meet the system design indicators.Simulations show that the bit error rates of1,1.5,and 2 MHz/s carrier data are less than 10–6 in indoor environments,wuich satisfies the requirement of indoor visible light communication positioning and simplifies substantially the complexity of the positioning system. |
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