In order to solve the problem of low positioning precision and poor stability of indoor positioning method based on received signal strength indication(RSSI)
a passive indoor positioning algorithm based on channel state information(CSI) is proposed.The algorithm uses Kalman filter to process the original CSI signal
combined with the Gaussian radial basis kernel function weighted K-nearest neighbor algorithm(RBF-KNN) and the confidence interval for perform indoor positioning.The experimental results show that precision of the proposed algorithm is higher than other algorithms.