Design And Implementation Of Indoor Positioning System Based On Multi-Photodiodes

At present,indoor positioning technology has been widely applied to various devices in indoor places,providing convenience for people's lives.Visible Light Positioning(VLP)has attracted much attention in recent years because of its high accuracy and other advantages.VLP can be classified into two categories: photodiode(PD)and camera-based positioning systems.Among them,PD-based positioning systems are more popular because of their low cost and easy deployment.However,the current common positioning algorithm based on a single PD receiver requires at least three lights to provide information,so it is difficult to locate in many actual scenes with only single or double lights.A multi-PD array indoor positioning system based on occlusion structure is designed in this thesis to solve these problems.First,an 8 PD array receiver is designed with a horizontal shielding structure.Then the difference of the received light intensity of each PD under the influence of the shielding structure is analyzed and the light propagation model under the shielding condition is established.Based on this model,the angle and distance measurement method of the receiver is designed.The angle measurement method establishes multiple equations according to the relationship between the PD exposure area and its PD direction angle,and then achieves the direction angle of the receiver relative to the LED.The measurement method for the distance converts the light intensity value of each PD into a collection of multiple distances through the light propagation model.It uses the average combination of distances with the smallest variance value as the final distance.Finally,according to the direction angle and distance information in different scenarios such as single light,dual lights,and multiple lights,the receiver is located.At last,an experimental environment is built for static testing.Experiments show that the positioning scheme in this thesis can achieve high-precision positioning in the single-lamp,dual-lamp,and multi-lamp scenarios.In the natural environment site of 3.6×3.6×2m~3,the average positioning errors are 14.18 cm,14.87 cm,11.35 cm,respectively in the single-lamp,double-lamp and multi-lamp scenes.This thesis proposes a multi-photodiode positioning system based on the shielding structure,which can effectively obtain high-precision positioning in various scenes.