XIII-th International Scientific and Technical Conference THE PART OF NAVIGATION IN SUPPORT OF HUMAN ACTIVITY ON THE SEA Naval University in Poland Institute of Navigation and Hydrography - 593 - Cezary Specht, Aleksander Nowak Naval University of Gdynia Institute of Navigation and Hydrography 69, Śmidowicza Str. 81-103 Gdynia Poland POSITION ACCURACY PROJECTING FOR TERRESTRIAL RANGING SYSTEMS Abstract The article presents computer program for terrestrial radionavigation system accuracy projecting and visualisation. It calculates theoretical position error based on DOP value and range error defined as a function of distance between user and station. The comparison between proposed and traditional methodology was done.