Research And Validation Of Visible Light Localization Method Based On Dual-Frequency Orthogonal Beacons

In response to the call to open the "last mile" in the field of positioning-indoor positioning,researchers in related fields have gradually started to study indoor positioning technologies,among which indoor positioning based on visible light has the advantages of high accuracy,low cost,no electromagnetic interference,and abundant spectrum resources in current research.Therefore,the work of this thesis starts from the implementation of visible light indoor positioning,so that the system can meet the demand of indoor high-precision positioning and reduce the cost of users.This thesis proposes a visible light positioning method based on dual-frequency orthogonal beacons,which solves the above-mentioned obstacles by using the differential phase and position relationship of dual-frequency orthogonal beacons to achieve high-precision indoor positioning,and completes the FPGA experimental verification.The specific work of this thesis is as follows:First,after a detailed introduction and analysis of the current common methods of indoor visible light,the simulation and analysis of direct LOS and non-direct NLOS links in visible light positioning technology using MATLAB programming,and after establishing the corresponding channel model,this thesis studies and analyzes the impact caused by noise on the positioning effect during visible light transmission,and the average signal-to-noise ratio received in the LOS channel The average SNR received in the LOS channel is 17.82 d B,and the average SNR received in the NLOS channel considering the wall reflection is 16.68 d B,which provides an effective reference for the subsequent indoor visible light positioning system based on the phase arrival difference PDOA.Secondly,a carrier allocation method based on dual-frequency quadrature beacons is designed for most of the visible positioning transceivers and high-precision synchronization at the LED network end,and an indoor visible positioning system based on dual-frequency quadrature beacons is designed on this basis,and the dual-frequency quadrature beacons are efficiently identified at the receiver end by FFT.It is analyzed that the dual-frequency quadrature beacon designed in this thesis can reduce the nonlinear error caused by the multipath effect,so that the dual-frequency quadrature beacon-based indoor visible light positioning system can be positioned based on the differential phase of the beacon without the synchronization of both transmitters and receivers.Based on the above positioning beacons,the particle filtering method of the traceless Kalman filter is introduced to eliminate the nonlinear errors caused by the multipath effect,and the semi-positive definite programming is used to solve the position solution under multiple constraints,and finally the simulation is compared with the traditional TDOA algorithm for time difference of arrival.level.Finally,the hardware circuit of the visible light positioning system based on the dual-frequency orthogonal beacon method is analyzed,designed and tested,taking into account the dual functions of LED lighting and positioning,as well as the system complexity and cost requirements.The designed hardware circuit and FPGA are used to perform sub-module hardware simulation and testing of the system modules to verify the feasibility of the algorithm proposed in this thesis without the need for synchronization of both transmitters and receivers or synchronization of beacons within the network equipment.In the experimental scene of 3m×3m×3m,36 preset coordinates were tested,and the average positioning error was 7.12 cm,which met the design requirements.