This paper presents a robotic platform as a mobile node suitable for indoor purposes focused on positioning. Ultrasonic sensors, as well as encoders, are used to calculate the node position. Using ultrasounds, position can be calculated with the time-of-flight of ultrasound signals and trilateration. Using encoders, the node position is calculated from a known starting point, adding the distance advanced by the motors. The precision achieved by the fusion of these two methods is greater than the one achieved by each method separately. The developed platform is based on the fusion of both methods to locate in space.