Research And Implementation Of High Precision Indoor Positioning System Based On Ultrasound

With the promotion of positioning application,the market demand for positioning system is growing,and the positioning requirements for the system are also increasing.In indoor environment,a high-precision positioning system is a challenge in current positioning design.Based on the principle of ultrasonic ranging,a high-precision indoor positioning method is proposed.The structure of the experimental system is given.The system hardware and software are designed.The system positioning experiment is completed.The causes and solutions of the error are analyzed.Linear fitting is used to correct the ranging equation and reduce the measurement error.Limited filtering and mean processing are used to improve the accuracy of the data.The coordinates are corrected to improve the positioning accuracy.In the positioning area,four known ranging nodes with radio frequency communication coordinates and ultrasonic ranging nodes are arranged to form a positioning base point.According to the ultrasonic ranging result of the mobile node and the positioning base point in the positioning area,the distance between the mobile node and each positioning base point is obtained,and these distances are then uploaded to the upper computer through radio frequency communication for being processed and calculated.The coordinates of the mobile node are obtained.Experimental results show that the measurement error does not exceed 3 centimeters and the dynamic response is quite good.After completing the design scheme of the ultrasonic positioning system,the hardware circuit and software design are introduced in detail.The hardware circuit is divided into the ultrasonic transmitting subsystem,the ultrasonic receiving subsystem and the data processing subsystem.The circuit design,the PCB design and the welding and debugging of the circuit board are completed.The software design includes the flow chart of each system,the compilation of system program and the compilation of upper computer.The bottom software is completed in C language under Keil uVision 4,the upper computer is completed in VB language under vb6.0,and the database is stored in Access database.Finally,the positioning system is built in the laboratory environment,and the debugging and error analysis of the system are completed.The ultrasonic positioning system designed and built in this paper can meet the requirements of indoor positioning and has application value.