Indoor Positioning System Based On Signal Strength And Ultrasonic Ranging

At present,outdoor navigation technology has been widely used in people's lives.In the indoor environment where satellite navigation systems are difficult to cover,the demand for location services is increasingly urgent.With the rapid development of economy and the rapid rise of intelligent manufacturing technology,accurate indoor location information is required in factories,warehouses,large-scale indoor venues,and personal location services.In special circumstances such as fire rescue and emergency evacuation,indoor positioning is particularly important.Therefore,a high-precision,low-cost,low-power,fast-response indoor positioning system is needed.Based on the principle of RF signal strength and ultrasonic ranging,this thesis proposes an indoor grid positioning method and system combining RF and ultrasound.In the positioning area of M×L block,positioning base points composed of an ultrasonic ranging module with a wireless communication function and a measurable signal strength are installed in each of the four corners of each grid.The moving target to be located first reads the signal strength values of several special positioning base points in the positioning area,reduces the positioning area according to the strength of the signal strength,and then performs accurate positioning through the ultrasonic ranging in the reduced area.The dissertation designs the hardware and software of the system,tests the static and dynamic positioning,and selects the key components and sets the parameters.The hardware system based on the single-chip microcomputer includes positioning base point module,moving target module,and wireless communication module;the software adopts modular design,flow chart of each program is given,and upper computer design is performed.In this thesis,the rough location area is determined by the intensity of RF signal strength,the ultrasonic distance measurement determines the exact location of the moving target,which greatly reduces power consumption,and has low cost and high precision.Different channels and address filters are used for data transmission,and a wireless ad hoc network system is established.The anti-jamming capability becomes stronger and the data transmission is stable.Linear compensation is performed on the ultrasonic ranging value,and then the moving coordinate filtering method is performed on the positioned coordinate value to make the data more reliable and accurate.The displayed coordinates are displayed on the visual interface to realize real-time tracking display.A large number of experiments were performed on the ranging data and positioning data,and error compensation and analysis were performed.The experimental results show that the static positioning deviation is no more than 4cm,and the dynamic positioning deviation is no more than 5cm.