Research On Indoor Wireless Location Technology Based On WIFI Network

In recent years, with the explosive growth of mobile Internet technology and the popularity of smart mobile terminal devices, there are many location-based services, such as making friends and searching around the surrounding, which depends on position technology. By the late 1990 s, GPS and other global position systems have made remarkable achievements in production and life. But they have disadvantages in penetrating buildings and other obstacles, then indoor environment is more complicated than outdoor environment. Therefore, the traditional outdoor position technology does not work in the indoor environment and the study of indoor position technology is very urgent. Looking around the world, researchers usually use ultrasonic, WIFI, RFID, infrared and other short-range wireless location technology in the field of indoor position.WIFI technology has many advantages such as wide coverage, low cost, easy to operate, and so on. And now in order to attract and serve the youth, many of the large indoor environments such as shopping malls, museums, airports, coffee shops have free WIFI hotspot, which making indoor position become a hot research.Research on the indoor positioning technology based on WIFI network and Fingerprint is the point. Analyze the principle of the technique of location fingerprinting, figure out the key issues of location and sum up the evaluation criteria of positioning system. Study a typical location fingerprint positioning algorithm, compare and analysis their scenarios. Figure out that the main aspects of positioning errors, improve positioning process, optimize the positioning algorithm, propose a new indoor location algorithm. This means that measure the averaged signal strength of sampling points in offline phase, then put the values into fingerprint database, then take advantage of the improved clustering technology for training fingerprint database. The data in the database is divided into a number of classes, the class which is mostly similar to the targeted point is reserved, remove others having low similarity, so we can reduce the searching space in matching algorithm and reduce the time complexity of the algorithm, therefore reduce the possibility of positioning error due to the received signal error of sampling point. After careful study of the clustering technology, the traditional positioning technology has been improved, reduce the impact of the initial number K of cluster, solve the problem of local optimal, reduce the time complexity of clustering algorithm, improve the calculation speed. Give full consideration of the different receiving ability of different mobile receivers and data error, optimize the weight coefficient of matching algorithm, give the point with strong signal and strong stability greater weight and give the point with poor signal and poor stability a little weight, improve positioning accuracy.Finally, in the same environment compare to two different positioning algorithm by using MATLAB simulation tools in the file of positioning accuracy, mean error, convergence and other aspects, the result verities the improved positioning algorithm effectively reduces errors and has higher positioning accuracy.