A position estimation method for indoor positioning includes filtering an initial position estimate that includes a corresponding covariance that reflects the quality of the geometry of the reference points and a previous initial position estimate that includes a corresponding covariance that reflects the quality of the geometry of the reference points by a Kalman filter to generate an updated previous position estimate, analyzing the updated previous position estimate to determine if the value is outside of a range, and constraining the updated previous position estimate based on the value being outside of the range.