%0 Journal Article %A Specht, Cezary %A Specht, Mariusz %A Dabrowski, Pawel %T Polish DGPS System: 1995-2018 – Studies of Reference Station Operating Zones %J TransNav, the International Journal on Marine Navigation and Safety of Sea Transportation %V 13 %N 3 %P 581-586 %D 2019 %U ./Article_Polish_DGPS_System_1995-2018_–_Specht,51,933.html %X The operating zone of a radio navigation system is one of its main operating features. It determines the size of a water body in which the system can be used, while guaranteeing vessels’ navigation safety. The DGPS system in the LF/MF range is now the basic positioning system in coastal waters around the world, which guarantees not only metre positioning accuracy, but it is also the only one to provide navigators with signals on positioning reliability. This paper describes and summarises over twenty years of studies dealing with the operating zone of the Polish DGPS reference station network. This paper is the fifth in a series of publications whose aim was to present in detail the process of installation, testing and long-term evaluation of the navigational parameters of the Polish DGPS system, launched in 1995. This paper includes the theoretical foundations of determination of the Dziwnow and Rozewie DGPS reference station operating zones in the years 1995-2018. Moreover, it presents the measurement results for the signal levels and the results of their analyses, which determine the station operating zones. %@ 2083-6473 %R 10.12716/1001.13.03.13