The WiFi Indoor Location Technology Based On The Fingerprint

With the rapid development of wireless communication technology, the WiFiindoor positioning technology that based on the location fingerprint is simple, low cost,high positioning accuracy, robustness, scalability, etc., has become a hot spot of indoorpositioning technology.Firstly, by RSSI location fingerprint data that sampling from the actual WiFienvironment, our article analyzed RF signal propagation characteristics in indoor fromthe point of view of the indoor positioning, and analyzed some factors that may affectthe positioning error, such as the number of access points, environmental interferenceand dissimilar terminal, All above analysis provided a theoretical basis for thepositioning algorithm design and positioning system deployment. For heterogeneousterminals RSSI quantitative error, this paper design using BP neural network fornonlinear calibration as the solution of such problems, the positioning system cansimultaneously support different types of terminals. And use a variety of terminal testdata, to contrast existing linear calibration method, BPNN calibration method caneffectively improve the positioning accuracy of the terminal under the existing system.Secondly, with the idea of iterative positioning, this paper used AP access pointsthat are already arranged in non-positioning system to provide joint assisted positioning,further improved the positioning accuracy and the positioning robustness of the originalsystem, and reduced the requirements of layout AP equipment. Moreover, this chapterprovided the solution to the problem of non-arranged AP may change.Finally, this paper combined the theoretical analysis and positioning methodswhich have been discussed above, designed and achieved a location-based fingerprintWiFi indoor positioning system prototype and made experimental validation using thesemethods in the actual WiFi environment. The experimental data show that the proposedscheme can improved positioning accuracy through the use of the existing AP AccessPoint, meanwhile reduced the requirements of the number and the positioning of APAccess Points.