Weighted Least Square Localization Algorithm Using the Unbiased Estimate of the Distance

Received signal strength based positioning technology has become a hot topic with the extensive coverage of the WiFi network. Due to the bad positioning performance of the existing received signal strength based localization algorithm, a weighted least square localization algorithm based on the unbiased estimate of the distance is proposed. In the proposed algorithm, firstly the unbiased estimate of the distance between the target and the sensors were calculated according to the received signal strength observation model. Then linear equations were established based on the distance calculation formula. After that, the unbiased estimate of the distance was substituted into linear equations to establish the linear least squares model on the source position, simultaneously calculated the noise covariance matrix of the linear least squares mode. Finally the estimation of the signal source position was obtained by weighted linear least square method. In the paper, full computer simulations had been done. Simulations results show that the positioning performance of the proposed algorithm is better than both traditional weighted least squares algorithm and best linear unbiased estimation algorithm under different positioning environment.