Research On Indoor Wireless Positioning Technology Based On WIFI

With the development of modern science and technology,location technology,especially the global positioning technology---GPS,has been very mature,fully able to meet the needs of people in the outdoor positioning.However,there are still a lot of problems in Indoors Positioning System,especially in building fire rescue personnel positioning,earthquake rescue personnel positioning.In addition,the construction area of modern buildings is more and more large Internal structure design is becoming more and more complex,we demand for indoor positioning technology urgently.Therefore,the positioning theory and technology research is very valuable.Ahead of time,conduct investigation and analysis on the present situation of indoor positioning technology.It is the important subject with how to improve the positioning accuracy.including Apple Corp is studying for iPhone indoor positioning software---Indoor Survey.Therefore designed and implemented based on LabVIEW indoor positioning system,and put forward the improved localization algorithm.Firstly,through theory and experiment,the factors that affect the RSSI and indoor positioning error are verified.Effects of RSSI are the major factors of people walking,Wireless AP antenna direction and different models of wireless AP.The main factors influencing the indoor positioning error are the sampling times and the sampling distance,selection of wireless AP,selection of DCM algorithm.Through the Matlab software to simulate a variety of experiments,and analysis of its results.Secondly,put forward the fingerprint indoor localization model based on the overall position,mainly consists of two stages: the stage of establishing the position fingerprint database and the online positioning stage.In order to solve the influence of RSSI instability on the location error,the average value of the off-line phase is obtained at the reference point,RSSI value as wireless AP.And the signal to be processed to filter,to eliminate the impact of noise.In order to enhance the accuracy of indoor positioning system,improve the traditional wireless AP online stage.Finally,an indoor positioning system based on WIFI module and LabVIEW is designed.The selection of the WIFI module model is USR-WIFI232-602,collect wireless signal mainly.The software part is through the LabVIEW programming language,design each module of the positioning system,including the acquisition of information module,set up location fingerprint database module and online positioning module.Through the actual measurement data,verify the accuracy of the positioning system.Through the experimental study shows,the positioning performance of this system is better,not only the positioning accuracy is high,and the system can also be a variety of filtering algorithm and DCM algorithm and the size of the K value to choose.