Research Of Indoor Localization Algorithm Based On RSSI

With the rapid development of wireless communication technology, the indoor positioning technology is getting more and more attention, indoor positioning technology can achieve precise positioning in large spaces such as shopping malls, libraries and other internal and therefore wide range of applications., so the application range is very wide. Currently there are indoor positioning technology infrared positioning, ultrasonic positioning, wireless LAN positioning, Bluetooth positioning, ultra-wideband positioning, compared with the mature technology of GPS technology, using indoor positioning technology of wireless LAN can be implemented with the help of the existing wireless WIFI network and has low cost, high positioning accuracy, programs to achieve simple.In this paper, the indoor location algorithm based on RSSI positioning, research mainly from three aspects:the characteristics of wireless channel and the loss of signal model parameter optimization model, kalman filtering, signal loss model parameter optimization.Compared with the outdoor wireless channel, the indoor wireless channel with propagation distance is smaller, complex indoor environment. According to the wireless signal propagation characteristics, signal strength decreases with increase propagation distance. This article will choose logarithmic ranging from loss model, according to the propagation loss in the process of two wireless devices can be measured distance method. And through the node localization algorithm such as trilateration method, maximum likelihood estimation method, to establish a equation to calculate locating node coordinates, by comparing simulation trilateration method and maximum likelihood estimation method of positioning effect, the maximum likelihood estimation method of the positioning precision is higher.As a result of the wireless signal propagation process is affected by the indoor environment, factors such as noise, acquisition of signal strength value volatility, will cause the positioning accuracy is affected. In order to make the collected RSSI value can reflect the actual measured value, eliminate noise to improve positioning accuracy, in this paper, the RSSI values obtained for kalman filter processing, and through the simulation test, the results show that the filter effect is better.Based on RSSI indoor localization method using log distance path loss model to predict the signal attenuation, the model parameters are fixed, however, ignores the complicated environment, this article will through linear regression fitting optimization attenuation parameter of the model. Finally in the WIFI environment used WirelessMon software acquisition RSSI values, using MATLAB to locate the experiment and analysis results, the experimental results show that the positioning effect is better.