Localization plays an important role in many applications such as robotic, signal processing and sensor networks. In the previous study, an indoor positioning system (ICKON) was developed. The ICKON uses only ultrasonic signals to calculate the position of mobile unit at cm level accuracy. For this accuracy, transmitter positions must be known in advance. These directly affect the mobile unit position calculation. In IKON system transmitters' coordinates are determined by manual measurements. It needs long time depending on number of transmitters. In this study, a mobile application is developed for automatic transmitter position calculation. The mobile application uses Time of Arrival measurement and Trilateration method for the position calculation.