The Kongsberg RADius is used in Qinsy as a Surface Navigation System and/or ARPA Target System. The system consists of an interrogator (usually placed on a vessel) and at least one transponder (usually in a fixed location). The interrogator sends a signal to the transponder, which reflects it, so that the interrogator can calculate a range and a relative bearing. Qinsy can use this data to calculate a position. Having more transponders available increases the accuracy of the positioning.