Research On WiFi Indoor Location Technology Based On Channel State Information

With the improvement of people's living standard,the demand for location-based services is getting higher and higher.Among them,the indoor positioning technology based on WiFi has been widely used.In the existing literature,the indoor positioning technology based on the received signal strength has become a mainstream scheme,but the multi-path interference in the complex indoor environment leads to its low accuracy and stability.This paper has done the following work to solve these problems.In this paper,the amplitude frequency characteristics of channel state information in WiFi network are analyzed and proposed an indoor positioning scheme based on CSI location fingerprint.The scheme utilizes the channel state information of WiFi physical layer to deal with the characteristics of multi-path effect to achieve high-precision indoor positioning.Firstly,the position fingerprint is constructed by using CSI in the complex environment with stable amplitude characteristics.Secondly,the high frequency noise of the collected CSI data is filtered out by the second order Butterworth low pass filter and the CSI data are weighted averaged after removing the bad data from the average 5%.Finally,a reference point location fingerprint database is established and the target location is determined by adopting WKNN localization algorithm.The indoor positioning scheme proposed in this paper not only satisfies the people's need for high-precision indoor location,but also further optimizes the stability of indoor location fingerprint location and improves the positioning accuracy effectively.The experimental results show that the method can obtain the average positioning accuracy of 1.1m and take one second as the time slice to collect the data to meet the real-time localization.