Recognition of the current location is important for a mobile robot to follow the planned path. Landmarks, which are assumed in the environment around the robot, are used to support this recognition. A mobile robot basically estimates its current location by dead-reckoning using the information of internal sensors. Information obtained by landmark measurement is used to cancel the estimation error which will grow as the travelling distance increases.
In this paper we propose a method to select the most suitable landmark among the measurable landmarks from a current position by evaluating the update of the estimation error distribution. We use the extended Kalman filter to update the distribution of estimation error. We show the update characteristics of two types of landmarks, such as line landmarks and point landmarks. For the evaluation of the update we use the width of the distribution ellipse perpendicular to the direction of the path. Through the navigation simulation the effectiveness of the proposed method is confirmed.