Research On Indoor Positioning Method Based On The Fusion Of Bluetooth AOA And IMU

Wireless positioning technology is one of the mainstream methods in the field of indoor positioning,and angle of arrival direction finding technology based on Bluetooth5.1 specification is a research hotspot in the field of indoor wireless positioning.However,indoor signal propagation is susceptible to interference,which makes it difficult for a single wireless sensor to meet the positioning requirements.So based on the complex indoor environment,this paper studies the indoor positioning method based on Bluetooth AOA and IMU from the two directions of angle measurement accuracy optimization and fusion positioning.Firstly,this paper reviews the relevant literature of domestic and foreign researchers,expounds the relevant research results in the field of indoor positioning,and analyzes the advantages and disadvantages of related indoor positioning technologies.At the same time,the development process of Bluetooth wireless technology and the related positioning methods based on Bluetooth signal are introduced,which focuses on AOA direction finding technology based on Bluetooth 5.1specification,and introduces the latest research and related commercial products at home and abroad based on AOA.Secondly,this paper analyzed the Bluetooth AOA signal data,introduced and derived the relevant positioning algorithm based on the arrival angle such as multiple signal classification algorithms and its improved algorithm.At the same time,the carrier position and attitude update algorithm based on inertial navigation is derived.Then,this paper introduces the relevant positioning accuracy evaluation index based on positioning technology,analyzes the direction finding accuracy of Bluetooth positioning system in indoor environment,and analyzes the interference factors of indoor related signals,proposes a signal optimization method based on nonlinear least squares to reduce the influence of signal interference on Bluetooth direction finding signal during indoor propagation.Finally,through simulation experiments,the feasibility of the proposed method is verified.Finally,this paper studies the fusion positioning of Bluetooth AOA and IMU in indoor environment.By analyzing the respective technical characteristics of Bluetooth AOA and IMU,a positioning theory framework based on the fusion of the two is proposed.At the same time,on the basis of fusion positioning,we combined with the two-dimensional position information of the carrier terminal given by the Bluetooth positioning system,and a carrier posture correction method based on fusion positioning is proposed to further improve the positioning accuracy.Finally,the test results based on the actual site show that the static and dynamic positioning errors of the single Bluetooth positioning system are 0.28 m and 0.37 m respectively,reaching the submeter positioning accuracy.After eliminating the signal interference by combining the nonlinear least squares method,the static and dynamic positioning errors were 0.13 m and 0.22 m respectively,and the positioning errors decreased by 53.6% and 40.5%.After fusing the Bluetooth positioning system with the inertial measurement unit,the dynamic positioning error of the fusion positioning system is about 0.097 m,of which more than 50% of the positioning error is kept within 10 cm,and the overall positioning accuracy reaches the centimeter-level positioning accuracy,which verifies the feasibility of the method proposed in this paper.