In order for a robot to follow a predetermined trajectory accurately, its position must be estimated accurately and reliably. This paper proposes a trajectory tracking control method for a non-holonomic mobile robot that utilizes both iGPS and odometry localization information to precisely calculate the robot's position. The iGPS is an indoor global positioning system that utilizes TV cameras mounted on the ceiling to locate the robot with respect to the world coordinate system, The iGPS localization information is sent to the robot via wireless LAN, and the robot estimates its position from this information and the robot's internal odometry. The experimental results show that the proposed method enables robust trajectory tracking, even after experiencing a significant disturbance.