Study On Some Key Techniques For Bluetooth-based High Precision Indoor Positioning Systems

In recent years,with the advent of the era of smart phones and mobile Internet,indoor map navigation technology has taken off gradually,and IDC reports show that indoor positioning technology has at least $500 billion in commercial value.In this context,many Unicorn companies are focusing on the field of indoor positioning,major domestic and foreign companies are also looking at the development prospects of the market,and increase the related areas of technical research and industrial investment,the introduction of indoor positioning solutions,promote indoor high-precision positioning technology and related technology innovation and popularization.At present,the demand of indoor positioning market is strong,but the indoor positioning technology has not reached maturity,and is far from a unified technology market,many existing indoor positioning systems often appear poor performance,low precision,high cost shortcomings.Location Based Service(LBS)is the main indoor positioning service.It uses automatic positioning equipment,combined with relevant algorithms and processors,to track and determine the specific location of indoor targets.Compared with outdoor positioning,indoor positioning has many special features.Generally speaking,indoor environment is usually more complex than outdoor environment.In the positioning process,the interference and change of the internal items are greater,and the non-line-of-sight factors are more.Ultra-wideband(UWB),infrared,geomagnetic,ZigBee,Radio Frequency Identification(RFID),WiFi,ultrasonic,Bluetooth and so on are the main indoor positioning technologies at home and abroad.Usually,Bluetooth positioning is based on Received Signal Structures.The positioning method of Received Signal Strength Indication(RSSI)has the advantages of low cost and convenient to use,but the positioning accuracy is not high.The indoor Bluetooth high-precision positioning system studied in this paper,which combines Bluetooth low-power 4.0,DOA,array antenna,array signal processing and other technologies,is based on Bluetooth low-power 4.0 technology,using array antenna,DOA positioning technology,can achieve 0.3m-1m positioning accuracy.It provides a new technical scheme for indoor high-precision positioning.Firstly,the theory of spatial spectrum estimation is introduced;secondly,DOA estimation algorithm and MATLAB simulation are studied,including MUSIC algorithm and simulation,ESPRIT algorithm and simulation;then,two-dimensional DOA estimation algorithm and Simulation for uniform circular array antenna are carried out on the basis of the above,including beam space conversion,UCA-RB-MUSIC algorithm,UCA-RB-MUSIC algorithm and simulation.ROOT-MUSIC algorithm,UCA-ESPRIT algorithm,and these algorithms are simulated and compared.Finally,the indoor Bluetooth high-precision positioning system scheme is proposed,which uses uniform circular array antenna and DOA estimation signal processing method to determine the relative direction of the target,using power.Rate tracking algorithm solves the problem of DOA estimation in multipath propagation.Constraint information central reference antenna array are used to further improve the positioning accuracy.