Research And Implementation Of WLAN Indoor Localization Based On Weighted APs

In recent years, due to the wide deployment of Wi-Fi access points (AP) in indoor environments, people can access Internet conveniently through wireless communication devices. Meanwhile, people need more and more location based services. For the reason that GPS cannot be applied to indoor environment and superiority of WLAN localization technologies, more attention has been paid for this academic sector. Among different WLAN localization methods, fingerprint localization algorithm has been widely used for its high localization precision, strong university and no need of additional devices.This paper studies the effect of on fingerprint localization form AP aspect, analyses the effect of line of sight (LOS) condition and quality factors on received signal strength (RSS) probability distribution. Through analysis of experimental results, proposes the idea to assign weights to different APs and an allocation method that is based on Fisher criterion with LOS condition factor a and AP quality condition factor β.To promote the self-adaption of fingerprint localization, this paper proposes a method to find signal space correlation nodes based on the variation trend of RSS. According to the method, first the localization area should be divided into different cells. Then the sensor nodes will be added to different RSS correlation cells as reference points to momentarily update fingerprint information. This improvement can reduce the effect of time variation environment on localization precision.Finally, this paper designs and implements a WLAN indoor localization system that can locate the position in fingerprint localization method. Under actual environment conditions, the method promoted by this paper is verified by experiments. The experimental result proves that compared with traditional fingerprint localization method, this new method proposed by this paper can improve localization precision significantly.Above-mentioned research work efficiently improves the performance of WLAN based indoor wireless localization system. It also provides reference method about AP selection and ability to adapt time variance environment for actual engineering application. Meanwhile, it also provides instance reference for engineering implementation.