Indoor location and navigation system is a popular issue with regarding to both commercial application and research study. The Cricket indoor location system provides location information, such as space identifiers and coordinates, to users. In our work, a system is designed to navigate a Pioneer 3-DX robot inside a room with complex environment through a smartphone user interface. Autonomous navigation between multiple rooms and obstacle avoidance are achieved. Factors that can affect the accuracy and speed of the Cricket system's performance are discussed. Users can have interactions with robot vehicle through a smartphone application. Moreover, to enhance the applicability of the system, a position estimation method is proposed which can enlarge the navigation area and improve localization accuracy. Experimental results are presented together with analysis and evaluation.