Research And Implementation Of Indoor Positioning Technology With Inertial Sensors And WiFi

In recent years,with the continuous development of mobile terminal technology,the demand for location service is increasing.The traditional GPS satellite positioning in the outdoor environment can be accurately located to the meter level.Because of the limitation of the GPS signal in the indoor environment,the signal can not be obtained,the positioning accuracy is greatly attenuated and can not meet the needs of the user.So indoor positioning technology is still a hot spot of research,and it has been applied in many fields,such as warehouse management,medical assistance,mobile location of indoor robot and so on.The continuous growth of the demand for indoor positioning technology has made many indoor positioning technologies,such as WiFi positioning technology,Zigbee positioning technology,ultrasonic positioning technology,infrared positioning technology and ultra wideband positioning technology springing up.Among them,the coverage of WiFi infrastructure is more and more extensive,making WiFi indoor positioning technology have its unique advantages.The share of mobile intelligent devices is expanding year by year.Most of the mobile intelligent devices are equipped with micro angle sensor,which makes the inertia more convenient.Through reading a lot of literature reference,this thesis analyzes the development of indoor positioning technology at home and abroad.In view of the positioning precision and hardware cost is the main factor restricting the development of indoor positioning,this thesis focuses on the study of WiFi indoor positioning technology and inertial sensor navigation and positioning technology.The traditional indoor positioning method based on WiFi is often affected by the interference of the multipath effect and the different errors of the mobile device.However,inertial navigation in sensors has accumulated errors and can not work accurately for a long time.In order to improve the indoor positioning accuracy based on the mobile terminal,combined with the advantages of WiFi fingerprint positioning and sensor inertial navigation technology,this thesis uses the WiFi fingerprint aided inertial sensor indoor positioning technology.This thesis mainly aims at the interference factors of WiFi positioning and the positioning precision of inertial sensors,analyzes the common techniques used in the current indoor positioning technology,and the positioning methods,and probes into the existing problems and development directions in the current indoor positioning,and proposes an improved scheme.Using the gyroscope,acceleration sensor and magnetometer with the mobile terminal,the pedestrian walking state is judged by the dynamic threshold adjustment algorithm,and the direction of the pedestrian movement is calculated by the direction detection algorithm.Then,the real-time analysis is made by the map matching particle filter algorithm,and the WiFi fingerprint location information and the inertial sensor navigation letter are combined.The joint localization algorithm is proposed to calibrate pedestrian position periodically.In view of the demand analysis of the system combining WiFi positioning and inertial sensor indoor positioning,the design scheme of the fusion system is proposed.Using the software platform of the Android system,through the Android Studio software development platform,the hardware support of the platform smart phone,the overall framework design of the positioning system,the analysis of the whole system business process and the communication protocols between each module in the positioning system.Then analyze the function of the server module and the client module separately,and realize the function of each module.Through the experimental test in the real environment,the results are compared with the results obtained by combining the indoor positioning with the inertial sensor and the indoor positioning with the inertial sensor separately in this thesis,respectively.It is concluded that the positioning accuracy can be effectively controlled within 2 meters by the proposed positioning method in this thesis.