Research On Visible Light Positioning Technology Based On Received Signal Strength

In recent years,the indoor location service(LBS)has attracted much attention,and there has been a rapidly growing demand in security management,robot navigation,and so on.At the same time,visible light communication(VLC)is developing rapidly in the field of wireless access networks with its advantages of green,anti-electromagnetic interference,and rich spectrum resources.VLC based indoor positioning has inherited the advantages of VLC,and has been extensively developed with its advantages of system stability and high positioning accuracy.In the existing VLC positioning systems based on the received signal strength(RSS),it is usually assumed that the receiver keeps upright to simplify the positioning model and most VLC localization algorithms consider that the LED follows the ideal Lambertian model.It shows that the existing VLC systems still have some practical problems to be overcome.The main research of this thesis focus on the above two problems,and the specific content is as follows:Firstly,this thesis expounds on the research significance,current research status,applications,and advantages and disadvantages of various positioning technologies.For VLC indoor positioning technology,the channel model,noise influence,and key system components,modulation technologies,multiple access technologies are analyzed in detail,and the VLC indoor positioning system scheme designed in this thesis is proposed.At the same time,this thesis takes the lead in introducing the beetle antennae search(BAS)algorithm to solve the nonlinear equations in the VLC positioning algorithm,and the good performance of the algorithm is verified in the simulation and practical experiments.Secondly,in order to solve the positioning accuracy problems caused by the fact that the radiation distribution of LED light source does not strictly follow the Lambertian model,a positioning optimization algorithm based on Lambertian model parameter estimation is proposed,which can effectively improve the positioning accuracy of the system by modifying and compensating the parameters of the radiation model of the LED light source.In the actual positioning process,the prior RSS fingerprint point information is collected,and the difference correction is made to the parameters at the receiver coordinates of each lamp by using this information.The positioning coordinates with higher accuracy are calculated by the optimized Lambertian model.Experimental results show that the proposed algorithm can reduce the average positioning error to about 1.6cm,which is about 60%higher than before the optimization.Finally,this thesis analyzes the VLC positioning model that introduces the direction angle of the receiver and then proposes a simultaneous positioning and orientating algorithm combining particle swarm optimization(PSO)and BAS,which can simultaneously calculate the three-dimensional position and three-dimensional direction of the receiver.Compared with the traditional VLC indoor positioning solution,the VLC positioning and orientating system proposed in this thesis does not require prior knowledge of the receiving end direction and can be used in more extensive application scenarios.