This paper describes a system to improve indoor navigation through use of radio frequency identification (RFID) technology. The terminal unit is an embedded system equipped with an RFID reader for localization, a mobile robot for navigation, and a combination of ultrasonic and IR sensors for obstacle detection and avoidance during navigation. To increase accuracy of an indoor guidance system, a triangulation method is proposed to accurately detect the location. While the proposed method can be verified by many methods, the accuracy is demonstrated through use of a mobile robot. It navigates to a designated location through continuously monitoring all RFID tags in the vicinity, localizing itself, and calculating the path to the destination.