Design And Realization Of Wireless Rfid Indoorpositioning System

The mature traditional positioning system is global positioning system (GPS), which can achieve a high accuracy outside while signal strength becomes weak inside. Taking account of the personal life convenient and efficient public services, it’s of great significance to research and develop the low cost and high-precision indoor positioning and navigation system in indoor environment. For example, the hospital patient care, exhibits and books browsing, public safety and military search and rescue and disaster scene.We study the indoor wireless positioning system and choose the passive one as the main investigation, in which the persons or things to be positioned don’t send request for positioning and navigation actively. Taking account of the properties and requirements of a passive indoor positioning system, we pick the received signal strength indicator as positioning algorithm, and radio frequency identification as positioning technology. The main contents are as following:(1) Compare and analyze existing indoor positioning algorithms based on RSS, choosing BP neural network algorithm with universality and high precision to fit the relation model of RSS and distance against to the fitting difficulties between them.(2) In order to improve the accuracy and stability of BP neural network algorithm, we optimize the BP neural network algorithm using the genetic algorithm and achieve it while it needs to cost more time to compute the algorithm.(3) In order to reduce the interference in the space on the positioning accuracy of the system, we propose a region determination mechanism (RDM), which can determine the coverage of the anchor nodes with the help of reference tags and the intersection of the coverage area.(4) Program and debug the human-computer interactive (HCI) control software needed by the RFID indoor positioning system using Visual Basic language, through which the computer can control and operate the hardware by the serial port, and realize to display and track the real-time positioning results. (5) Design the peripheral circuits of RFID reader using PR9000RF chip and the reader antenna. Then build the indoor positioning system experimental platform, using which to verify the algorithm and scheme of the positioning system, to obtain a high positioning accuracy.