Since the end of the second world war hyperbolic position-fixing systems have been available for use by merchant vessels. These systems originated in military requirements. Today for the navigation of merchant ships a number of existing systems can be used, such as Decca, Loran C, Omega, Transit and Cikada, the two latter being satellite navigation systems. Transit became operational in 1964 for military use and in 1967 the system was made available for use by merchant shipping.